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PSM3750 - NumetriQ

1. PON CME EXE DDE QYE OPC bit 0 OPC operation complete cleared by most commands set when data available or sweep complete bit 2 QYE unterminated query error set if no message ready when data read bit 3 DDE device dependent error set when the instrument has an error bit 4 EXE execution error set when the command cannot be executed bit 5 CME command interpretation error set when a command has not been recognised bit 7 PON power on event set when power first applied or unit has reset The bits in the standard event status register except for OPC are set by the relevant event and cleared by specific command ESR CLS RST OPC is also cleared by most commands that change any part of the configuration of the instrument such as MODE or START 5 3 5 2 PSM3750 user manual Serial Poll status byte ESB MAV FDV SDV RDV bit O bit 1 bit 2 bit 4 bit 5 RDV SDV FDV MAV ESB result data available set when results are available to be read as enabled by DAVER Sweep data available set when sweep results are available to be read as enabled by DAVER fast data available streaming set when data streaming results are available to be read as enabled by DAVER message available set when a message reply is waiting to be read standard event summary bit set if any bit in the standard event status register is set
2. S OUT ZZ Lor T CPU LF 39 LP ale Z FPGA EG le CH2 27 DSP on CH3 aa This general purpose structure provides a versatile hardware platform that can be configured by firmware to provide a variety of test functions including Signal generator Two channel true rms voltmeter Phase angle voltmeter vector voltmeter Frequency response analyser gain phase analyser Harmonic analyser With additional external interfaces such as current shunts other functions are possible True rms current meter LCR meter Power meter NumetriQ is configured to perform the required test function by simple user menus or can be controlled remotely via a serial interface RS232 or optionally LAN interface or GPIB interface 1 2 PSM3750 user manual The programmable nature of the instrument means that new functions can be added as they become available or existing functions can be enhanced by simple firmware download 1 3 PSM3750 user manual 1 1 Generator output The output sinewave is generated by direct digital synthesis DDS Amplitude is set in 2 stages a fine control and a coarse control to give good resolution over the whole range The output has a variable offset added is filtered and is buffered by a high speed high current buffer There is also an earth referenced TTL Sync output for oscilloscope synchronization etc constantly running at the selected gen
3. PSM3750 user manual Appendix D Configurable parameters All parameters can be accessed using the CONFIG command CONFIG parameter CONFIG parameter data Number Function System parameters 1 operating mode 3 bandwidth auto or wide 4 autozero manual or auto 5 blanking disable 6 phase convention 7 main output on off 8 line drawing on off 9 keyboard beep on off 11 low frequency mode 12 user window size 13 measurement speed 14 filter type 15 filter dynamics 16 baud rate 17 program step enable 18 sweep steps 19 sweep start frequency 20 sweep stop frequency 21 single sweep continuous sweep 22 auto conditions 23 auto shunt Input parameters 24 enable channel 1 25 enable channel 2 26 input range channel 1 27 input range channel 2 28 input ranging channel 1 29 input ranging channel 2 D 1 38 39 40 41 42 43 44 45 47 48 49 51 52 53 54 55 58 59 66 67 PSM3750 user manual coupling channel 1 coupling channel 2 scale factor channel 1 scale factor channel 2 external shunt channel 1 external shunt channel 2 input connection channel 1 input connection channel 2 General parameters 5 6 digit resolution phase reference output scaling output resolution Display parameters zoom level function zoomed on 1 function zoomed on 2 function zoomed on 3 function zoomed on 4 display type Signal generator parameters generator frequency generator amplitude generator offset
4. Conforms to the requirements of Council Directives 2004 108 EC relating to electromagnetic compatibility EN 61326 2006 2006 95 EC relating to safety of laboratory equipment EN 61010 1 2010 July 2013 Eur Ing Allan Winsor BSc CEng MIEE Director Newtons4th Ltd PSM3750 user manual WARRANTY This product is guaranteed to be free from defects in materials and workmanship for a period of 36 months from the date of purchase In the unlikely event of any problem within this guarantee period first contact Newtons4th Ltd or your local representative to give a description of the problem Please have as much relevant information to hand as possible particularly the serial number and release numbers press SYSTEM then LEFT If the problem cannot be resolved directly then you will be given an RMA number and asked to return the unit The unit will be repaired or replaced at the sole discretion of Newtons4th Ltd This guarantee is limited to the cost of the NumetriQ itself and does not extend to any consequential damage or losses whatsoever including but not limited to any loss of earnings arising from a failure of the product or software In the event of any problem with the instrument outside of the guarantee period Newtons4th Ltd offers a full repair and re calibration service contact your local representative It is recommended that NumetriQ be re calibrated annually PSM3750 user manual ABOUT THIS MANUAL
5. cccceeeeeeeeeeee ees 9 5 10 True RMS Voltmeter sssssnsssrrrerrrrerrrrrrrrrsrrere 10 1 10 1 RMS voltmeter Specification ccccccecceeeeeeeeeeeeeeeas 10 5 11 Frequency response analyser cc ce eeeeee cece ee eee es 11 1 11 1 Frequency response analyser specification 55 11 4 11 2 Feedback Loop Analysis quick user guide 055 11 5 12 Phase angle voltmeter vector voltmeter 12 1 12 1 Phase angle voltmeter specification 12 4 13 Power meter ssssesserssrerosronronrerrersrrerrsrenre 13 1 13 1 Power meter specification cccceceeeseeeeeeeeeeeeeees 13 5 T4 FERME TE a me rr area i a ae a a i 14 1 14 1 LCR meter specification sssssssssrsrrrrrrrrreressrrrrrrre 14 7 15 Harmonic analyser ssssssrssrserrerresrrrerrerrsrere 15 1 15 1 Harmonic analyser specification cccceeeeee eee eeees 15 4 16 Transformer AnalySeP ccc ccccceceeee seen ene eeeeees 16 1 IGE FUPNS Patio aici teen eines wean deren meee sees 16 3 16 2 Inductance amp leakage inductance c cece eee enna 16 4 16 3 AC resistance and Q factor cece cc cccecceeceeeeseeeeeeeees 16 5 10 4 VG r sistance rer airna cane senan a EANA AAAA NENE rare dues 16 5 16 5 Interwinding capacitance ccc cece eee e este eee eeeaeeeeas 16 6 16 6 MagnetiSing CUIreNnt cccccccee cece esas teens ere rr kerner 16 7 16 7 Retur OSS ionerne E EEE EE 16 8 16 8 Insertion loss soci
6. IEEE address LAN enable Alarm functions alarm data type high threshold low threshold latching type sounder enable Analogue output parameters analogue zero analogue scale Alarm functions alarm 2 data alarm 2 type alarm 2 high threshold alarm 2 low threshold D 4 173 174 175 177 178 179 180 181 186 188 190 192 193 194 195 PSM3750 user manual Graph functions graph 2 manual auto graph 2 maximum graph 2 minimum Phase angle voltmeter parameters computation LVDT scaling manual null meter ranging null maximum phase offset Trim parameters ac trim enable ac trim level trim tolerance Other parameters log linear sweep graph scaling manual auto manual graph scaling maximum manual graph scaling minimum D 5 PSM3750 user manual Appendix E Contact details Please direct all queries or comments regarding the NumetriQ instrument or manual to Newtons4th Ltd 30 Loughborough Rd Mountsorrel LOUGHBOROUGH LE12 7AT United Kingdom Tel 0116 230 1066 international 44 116 230 1066 Fax 0116 230 1061 international 44 116 230 1061 E mail address sales newtons4th com office newtons4th com Web site www newtons4th com At Newtons4th Ltd we have a policy of continuous product improvement and are always keen to hear comments whether favourable or unfavourable from users of our products An example comment form can be found at the end of this manual if you have a
7. components may be separately filtered to minimise noise 15 1 PSM3750 user manual The single harmonic and the thd are expressed relative to the fundamental either as a percentage or in dB as selected via the HARM menu NumetriQ can operate either in real time mode at a single frequency where the measurements are filtered and updated on the display or it can sweep a range of frequencies and present the results as a table or graphs The frequency points to be measured are specified with three parameters number of steps start frequency end frequency NumetriQ computes a multiplying factor that it applies to the start frequency for the specified number of steps Note that due to compound multiplication it is unlikely that the end frequency will be exactly that programmed The frequency sweep is initiated by the START key and when completed the data can be viewed as a table or graphs or printed out The window over which the measurements are computed is adjusted to give an integral number of cycles of the input waveform In real time mode the results from each window are passed through a digital filter equivalent to a first order RC low pass filter in sweep mode each result comprises a single window without any filtering Very good results can be obtained in a reasonable time using the medium speed setting e g 50 points x 1 3s 17s for the very best results use the slow setting 50 points x 2 5s 125s or 2 minutes 5 s
8. 31 dB 0 00004 dB kHz wide 0 01 dB 0 001 dB kHz phase accuracy 0 025 auto 0 05 0 00025 kHz wide 0 025 0 002 kHz CMRR typical 160dB 230V 50Hz 140dB 100V 1kHz 70dB 10V 1MHz lt 50MHz lt 5MHz lt 10kHz lt 5MHz lt 50MHz lt 5MHz lt 10kHz lt 50MHz lt 5MHz step rate 1 20s 1 3s or 2 5s approx Conditions 232C 528C ambient temperature instrument allowed to warm up for 230 minutes ac dc coupling autoranging or manual ranging gt 1 3 range signals gt 10mV 11 13 PSM3750 user manual 12 Phase angle voltmeter vector voltmeter A phase angle voltmeter or vector voltmeter or phase sensitive voltmeter measures the signal at one input compared to the phase of the signal at a reference input The results may be expressed as magnitude and phase or as separate in phase and quadrature components NumetriQ measures the in phase and quadrature components at the fundamental frequency using DFT analysis as described in the section on frequency response analysis CH2 the measurement input is phase referred to CH1 the reference input The individual components are filtered separately to minimise the effects of noise which would have random phase and would therefore be filtered out The true rms of the input signals is also computed CH1 and CH2 may be voltage inputs or may use external shunts From the phase referred fundamental components a jb the follo
9. 4 5 TIMES Flashing Red Box appears around the Coupling selection Press gt Flashing Red Box appears around ac dc ac options Press J Select ac only Press ENTER Flashing Red Box appears around ac selection Press HOME Flashing Red Box now disappears and ac is selected Press HOME Display returns to measurement window To change any of the other Input settings follow steps as above to enable the parameters to be amended 11 8 PSM3750 user manual input autoranging minimum range ie J a coupling CHANNEL 2 RANGING direct full autorange 3m 1 0000 ac lt channel 1 ranging Action Result Press CH 2 Channel 2 Control Menu appears Press 5 TIMES Flashing Red Box appears around the Coupling selection Press gt Flashing Red Box appears around ac dc ac options Press J Select ac only Press ENTER Flashing Red Box appears around ac selection Press HOME Flashing Red Box now disappears and ac is selected Press HOME Display returns to measurement window 11 9 Action Press SWEEP Press y Press 100 Press ENTER Press J Press 250k Press ENTER Press J Press 100 Press ENTER Press HOME PSM3750 user manual Frequency Sweep Data Settings FREQUENCY SWEEP CONTROL sweep start 100 00 Hz sweep end 250 00k Hz steps 100 steps sweep generator when complete
10. 4 1 4 1 Display ZOO ME rar cuinneviencnncernt ETOT OETA ARORA E ENTA 4 1 4 2 Program store and recall s ssssssssssssrrrrrrrrrrrrreeesse 4 2 4 3 Zero COMPENSATION ccccc ccc eeseeeeeeeeseeeeaeeeeaeeeeaneenes 4 3 4 4 Alarm TUN CHON issa e a a TAAR 4 4 4 5 Analogue output cece cee eeee cece eeeeeeeeeeeeaee sean eeene ees 4 6 4 6 Data MONG sacle te cx over oiediasncoxdtererordiennseritemeeaedeckecere 4 7 4 7 Sweep results store and recall cccceeeeeeeeeeeeeeeeeas 4 8 Using remote control ccccceceeeeseeeeeeeeseeeeeeees 5 1 5 1 Standard event status register ssssssssssrrrrrrrrrrrre 5 3 5 2 Serial Poll Status byte sssssssssrrrrrrrreesssrrrrrrrrrrrrre 5 4 5 3 RSZ3ZCONNECOAS SEE ED ED rr EAE rE 5 5 System o pH ONS arr a AE et eee ed 6 1 6 1 User daterjisn scien chs See ian en acai tue ee hte been 6 3 Measurement Options ccccceecseeeeeeeseeeeeeeeeeues 7 1 7 1 ACQU Acquisition OPtIONS seeren tenn ees 7 1 7 2 DACA Gi ea leche oy RES ESE SEES NESS E SETE ave vee areas 7 4 7 3 SWEEP Frequency sweep OPTtiONS cccceeeee eee eens 7 6 7 4 TRIM Trim function ang Picea acct cen ececictde leased heteneltadon ha bects lee 7 8 Output control sooren eaa E E aE tenis 8 1 8 1 Generator specificationS sssserrrrrreesssrrrrrrrrrrrrre 8 3 PSM3750 user manual 9 InputChannelS s0c lt 2 ss0s4scttacniesseadtadiagueetieeisaei se 9 1 9 1 Trimming x10 oscilloscope PrObeS
11. 7 3V 3 16V 8 10V 10V 9 30V 31 6V 10 100V 100V 11 300V 316V 12 500V 1000V Because of slew rate limitations of the input amplifiers the maximum input signal that can be accurately measured varies with frequency frequency max input level MHz peak V rms V 5 500 350 10 300 200 15 200 140 20 150 100 25 120 80 30 100 70 35 75 50 40 50 35 50 40 25 The input ranges may be selected manually or by autoranging default The start range for autoranging may be selected if it is known that the signal will not be below a certain level 9 2 PSM3750 user manual There is also an option to autorange up only so that a test may be carried out to find the highest range Once the highest range has been determined the range can be set to manual and the measurement made without losing any data due to range changing Pressing the HOME key or sending TRG restarts the autoranging from the selected minimum range When in an input channel menu the ZERO key provides a quick way to lock and unlock the range When no flashing box is visible in the input channel menu and autoranging is selected pressing the ZERO key selects the range that the instrument is currently using and sets the autoranging to manual thus locking the range and preventing further autoranging Pressing the ZERO key again returns to full autoranging from the bottom range For most measurement functions full autoran
12. CH3 menu Press TRIG and the scaling factor for channel 3 will be automatically adjusted to a number about 10 Press HOME to exit the menu and observe that the readings for CH1 and CH3 are again about the same 9 6 PSM3750 user manual 10 True RMS Voltmeter The RMS voltmeter measures the total rms of the signal present at the input terminals to the bandwidth of the instrument gt 1MHz Care must be taken when measuring low signal levels to minimise noise pick on the input leads The RMS voltmeter measures the elementary values rms dc peak surge mean And derives the values ac dBm crest factor and form factor The rms value of a periodic waveform v 9 is given by 27 rms vI 1 27 v7 do 0 For a sampled signal the formula becomes i n 1 rms v 1 n gt vil i 0 Where n is the number of samples for an integral number of complete cycles of the input waveform These are fundamental definitions that are valid for all waveshapes For a pure sinewave the formulae equate to peak V2 but this cannot be applied to other waveshapes NumetriQ computes the true rms value from the fundamental definition for sampled data 10 1 PSM3750 user manual The dc present is given by 27 dc 1 27 vb do 0 For a sampled signal the formula becomes i n 1 dc 1 n gt vil i 0 Where n is the number of samples for an integral number of complete cycles of the input waveform Having com
13. PSM3750 has of number of separate measurement functions that share common resources such as the keyboard and display Accordingly this manual first describes the general features and specification of the instrument as a whole and then describes the individual functions in detail Each function is described in turn in its own chapter with details of the principles on which it is based how to use it the options available display options specifications etc Detailed descriptions of the RS232 command set is given in the separate manual PSM3750 communications manual Revision 1 01 This manual is copyright 2013 Newtons4th Ltd and all rights are reserved No part may be copied or reproduced in any form without prior written consent 3 July 2013 N PSM3750 user manual CONTENTS Introduction general principles of operation 1 1 1 1 Generator OUP Ul ane seere a 1 4 1 2 Voltage INPUTS co cies eaaa asc a a A ected 1 5 Getting Started eerie eraai EEE E EE 2 1 2 1 Biatora lt o r E 2 1 2 2 Keyboard and COntrols cccccecceeseeeeeeeeeaeeeeeeeeneees 2 3 2 3 Basic operati N ecne a aoe te 2 4 Using the MenuUS sssssrssrrsrrrrrrerrrrrrerresrrsrrrere 3 1 3 1 Selection from a list sssssssssssssnnrrrrrrrrresssrrrrrrrrrrrrre 3 3 3 2 Numeric data entry sssssrrssrsessssrrrrrrrrrrrrrereessee 3 4 3 3 TOXE SOV YDE Eee SEER a a a E aie aE 3 5 Special FUNCTIONS mat sired on akd aa a ek aiea
14. a reasonable time using the medium speed setting e g 50 points x 1 3s 17s for the very best results use the slow setting 50 points x 2 5s 125s or 2 minutes 5 seconds 14 5 PSM3750 user manual The ZOOM function can be used to select up to four parameters from the display when in real time mode It has no function following a sweep Although it is most usual to use the NumetriQ generator when performing LCR measurements there may be circumstances where this is impractical for example measuring the inductance of a transformer primary winding under load In this case turn off the NumetriQ generator OUT menu and the frequency reference for the analysis is measured from channel 1 Provided that the signal is clean enough for an accurate frequency measurement and for DFT analysis the frequency does need to be accurately known then the measurements can be made reliably When using an external frequency reference there can be no sweep function 14 6 PSM3750 user manual 14 1 LCR meter specification LCR meter frequency 10uHz to 50MHz own generator 20mHz to 50MHz external source measurement type DFT analysis measurements L C R ac Q tand impedance phase admittance series or parallel circuit conditions auto or manual display numeric values table of sweep results graph of any measurement ranges 100pF to 100uf with external luH to 100H shunt 19 to 1MQ ranges 1lpF to 1000uF with IAI2 10nH
15. as well as the corresponding bit in the standard event status enable register set by ESE 5 4 PSM3750 user manual 5 3 RS232 connections The RS232 port on NumetriQ uses the same pinout as a standard 9 pin serial port on a PC or laptop 9 pin male D type Pin Function Direction 1 DCD in weak pull up 2 RX data in 3 TX data out 4 DTR out 5 GND 6 DSR not used 7 RTS out 8 CTS in 9 RI not used NumetriQ will only transmit when CTS pin 8 is asserted and can only receive if DCD pin 1 is asserted NumetriQ constantly asserts 12V DTR pin 4 so this pin can be connected to any unwanted modem control inputs to force operation without handshaking NumetriQ has a weak pull up on pin 1 as many null modem cables leave it open circuit In electrically noisy environments this pin should be driven or connected to pin 4 To connect NumetriQ to a PC use a 9 pin female to 9 pin female null modem cable 1 amp 6 4 2 3 3 2 4 1 amp 6 5 5 7 8 8 7 5 5 PSM3750 user manual 6 System options Press SYSTEM to access the system options The time and date are maintained by a battery backed real time clock Time is expressed in 24 hour format The display is normally in colour but it can be set to black on white or white on black There is a choice of screen brightness high suits most typical environments but low may cause less eye strain in low light conditions Measure
16. frequency refer to the chapter on gain phase analysis for the formulae for DFT analysis This technique gives good results even on lossy transformers The polarity of the windings is indicated by a positive turns ratio for in phase windings and negative ratio for inverted windings A nominal number of turns may be entered using the SETUP menu if Known and NumetriQ will then also display the computed number of turns As the inputs are independent of the output it is possible to energise a third winding when measuring turns ratio or only two windings may be used TO manually connect a transformer for turns ratio connect the NumetriQ output to the winding to be energised and the inputs to the two windings for the ratio Note that when using the transformer analyser fixture the transformer is always energised through the source resistance Pressing ZERO makes the turns ratio read 1 1 and the computed number of turns equal to the value entered via SETUP This allows accurate testing of transformers or chokes against a known good reference Press ZERO followed by DELETE to restore true turns ratio measurement 16 3 PSM3750 user manual 16 2 Inductance amp leakage inductance The inductance of a winding is computed from the complex ratio of CH1 voltage across the winding divided by CH2 current through the winding using DFT analysis at the fundamental frequency refer to the chapter on gain phase analysis for the fo
17. graph 1 scaling graph 2 scaling frequency marker Result Frequency Sweep Control Menu appears Flashing Red Box appears around the Sweep Start selection Sweep Start now requires setting 100 now appears in the Sweep Start Option 100Hz has now been selected for the Frequency Sweep start Point Flashing Red Box appears around Sweep End selection Sweep End now requires setting 250k now appears in the Sweep End Option 250 KHz has now been selected for the Frequency Sweep end Point Steps Option now selected Steps for plotting Frequency now requires setting 100 now appears in the Steps Option 100 Steps has now been selected for Frequency Plotting Display returns to measurement window 11 10 PSM3750 user manual Perform Sweep and Review OUTPUT ON FREQUENCY RESPONSE ANALYZER 14 13 39 gain margin 13 2dB 7 027kHz phase margin 049 2 2 300kHz 50 000 dE 30 000 180 00 phase 100 000Hz 200 087 kHz Action Result Press SWEEP Frequency Sweep Control Menu appears Check Sweep data parameters as Frequency Sweep screen Press SWEEP Display returns to measurement screen Press START Frequency Sweep will begin Press GRAPH View all data from sweep keep pressing Graph to view more results Press TABLE View data from all plotting points Press REAL TIME Display returns to measurement window 11 11 PSM3750 user manual Screen Print Options REMOTE SETTINGS r
18. or three input channels are fully isolated from each other and earth The two channels are controlled independently but sampled synchronously Each input channel may be selected to be direct external shunt external attenuator If the external shunt option is selected the data is scaled by the shunt value entered under the relevant channel menu and the units are displayed in Amps Any resistor can be used as a shunt or precision low inductance current shunts are available as accessories Current transformers can be used if fitted with an appropriate burden resistor Note that the external shunt input polarity is reversed compared to that of the voltage input ie the input becomes non inverting and the input becomes inverting This is so that the capacitance to ground of the probe cable screen is driven with the lower source impedance in order to minimise errors at high frequency Note that some modes force the input channels to be voltage or current automatically eg the power meter defaults to channel 1 as voltage and channel 2 as current This automatic selection can be overridden if required The input ranges have nominal full scale values set with a ratio of 1 V10 from 3mvV to 300V and a top range of 500V This gives the following ranges 9 1 PSM3750 user manual range reference nominal full scale 1 3mV 3 16mV 2 10mV 10mV 3 30mV 31 6mV 4 100mV 100mV 5 300mV 316mV 6 1V 1V
19. setup keys provide access to the menus and are used for numeric data entry The function keys FRA PAV LCR RMS POWER and SCOPE are also used for entering the multipliers G M k m u n for date entry and letters for text entry 2 3 PSM3750 user manual 2 3 Basic operation The required function can be selected by pressing the function key FRA PAV LCR RMS POWER or SCOPE Pressing the same function key again brings up the menu options specific to that function For example press PAV to select phase angle voltmeter mode press PAV again to gain access to the PAV specific menu options Alternatively press MODE to bring up the function specific menus There are a number of menus available to configure the instrument All of these menus are directly accessible with one press of the appropriate menu key The cursor keys allow navigation around the menus and also control the generator when not accessing a menu For example to turn on the output press OUT to bring up the generator control menu press UP to select the output on off option press RIGHT to select the output from the available options Press ENTER or HOME twice to exit the menu Press FRA to select frequency response analyser mode and the instrument will now display the gain and phase of the transfer function of the circuit under test at the spot frequency specified by the output control menu Press LEFT or RIGHT to adjust the frequency Press UP or DOW
20. the bandwidth is either 5MHz wide or 100 KHz low to minimise noise when making measurements at low frequencies 7 3 PSM3750 user manual 7 2 Datalog NumetriQ can store and display measurements recorded at regular intervals over a time period Each data record consists of the elapsed time and up to four data values selected by ZOOM The actual interval between data points is governed by the measurement speed and the datalog interval NumetriQ stores the next available measurement after the datalog interval has elapsed the actual elapsed time is attached to each datalog record is displayed with the data on the table or each graph and returned with each record over the communications RS232 USB LAN or GPIB The data values may be stored to RAM or directly into either internal non volatile memory or USB memory stick as each value becomes available The non volatile option is useful for acquiring data over long periods to prevent the loss of data in the event of a power failure The RAM datalog can hold up to 32000 records if one value is selected more than 12000 records if four values are selected Data that has been stored into RAM may be subsequently transferred to non volatile memory using the PROG menu For high speed data acquisition the datalog interval may be set to zero so that each measurement is stored The measurement interval is controlled with the speed option in the ACQU menu Using the window op
21. the channel has been set for use with an external shunt then the value of the shunt can be entered The secondary channel has a control to adjust the gain so that common mode rejection may be maximised when using oscilloscope probes 9 4 PSM3750 user manual 9 1 Trimming x10 oscilloscope probes To minimise the loading effects at high frequencies x10 oscilloscope probes can be used with NumetriQ For optimum performance the probes need to be trimmed to match the input capacitance of the instrument and the probes need to be corrected for gain errors A small plastic screwdriver is provided with each probe for this purpose In all there are three processes that must be carried out to optimise the performance probe trim probe scaling Connect the instrument output across a convenient resistor anything above 1k using the supplied BNC to crocodile clip output lead Connect the probes from the input channels across the resistor Observe the colour of which probe connects to each of the four input terminals for future use Press OUT and set the generator to 1kHz squarewave with 2V amplitude Press HARM to invoke harmonic analyser mode and select third harmonic Set all probes to x1 To trim the probes connected to the main inputs The measured third harmonic should read 33 33 0 05 Select x10 on one of the probes and adjust the trimmer in the body of the probe until the third harmonic again reads the same value Switch th
22. to 10kH 1mQ to 500MQ basic accuracy 0 1 tolerance of Shunt sweep step rate 1 20s 1 3s or 2 5s approx Conditions 232C 52C ambient temperature instrument allowed to warm up for 230 minutes ac dc coupling autoranging or manual ranging 1 3 range using impedance interface adaptor 14 7 PSM3750 user manual 15 Harmonic analyser The NumetriQ harmonic analyser computes multiple DFTs on the input waveforms in real time refer to the chapter on frequency response analysis for the formulae for DFT analysis There are three modes of operation single harmonic difference thd and series thd In single harmonic mode the specified harmonic is displayed both in Volts and as a ratio to the fundamental in either thd mode the computed thd and a specified harmonic are displayed as a ratio to the fundamental In difference thd mode the thd is computed from the rms and fundamental thd 1 h V rms2 h 2 In series thd mode the thd is computed from a series of up to 64 harmonics i n thd 1 h V gt hi where h is the i harmonic i 2 In series mode the magnitude and phase of all the harmonics can be seen as a table or the magnitudes can be displayed as a bargraph which changes in real time with the measurements When viewing the bargraph ZOOM and ZOOM change the vertical axis by a factor of 10 In all cases the harmonics are phase referred to CH1 fundamental so that their in phase and quadrature
23. under test plugs into an IEC mains outlet on the adaptor which contains an_ isolating voltage transformer and current transformer with precision low resistance shunt The adaptor is fitted with an IEC mains inlet for use with an appropriate mains lead When the adaptor is plugged into the mains and the mains switched on the appliance is energised and NumetriQ can be used to measure the power or harmonics Leave the NumetriQ generator off OUT menu so that it will synchronise to the mains frequency Part numbers 500 058 IEC 10A power meter adaptor A 2 PSM3750 user manual 750 6000 output adapter The generator output from the NumetriQ has a series impedance of 509 The output adapter fits directly onto the front of the instrument and provides 2 outputs 75Q via a BNC connector 6002 via 4mm sockets There are two versions of the adapter that have different Spacing between the 4mm sockets y2 12 5mm as commonly used for communications 34 19mm as standard on instruments In both cases the red connector carries the output signal the green or black connector is OV connected to earth via the NumetriQ chassis The impedance conversion is resistive and does not limit the frequencies available from the generator dc coupled When driving into the characteristic impedance 75Q or 6002 as appropriate the voltage delivered to the load will be half that delivered into open circuit Matching the source to the lo
24. ER then HOME twice to return to the measurement window 11 6 PSM3750 user manual Gain and Phase Margins Enable Disable mode speed smoothing smoothing response computation 1 offset gain phase margins graph MEASUREMENT SETTINGS frequency response analyzer fast normal auto reset ch2 chi 0 0000 dB enabled phase Action Press MODE Press 4 7 TIMES Press gt Press J Press ENTER Press HOME Press HOME Result Measurement Settings Control Menu appears Flashing Red Box appears around the Gain Phase selection Flashing Red Box appears around disabled enabled options Select Enabled Option Enabled Option has now been selected for the Gain Phase margins Flashing Red Box now disappears Display returns to measurement window Depending on the actual measurements to be made it may also be necessary to Use the 4 key to step down the screen until the Flashing Red Box appears around the Speed Setting Then select the desired speed from the drop down list Press ENTER then HOME twice to return to the measurement window 11 7 PSM3750 user manual Setting Channels 1 amp 2 Input Ranges amp Coupling CHANNEL 1 RANGING input direct autoranging full autorange minimum range 3m scale factor 1 0000 coupling ac channel 2 ranging gt Action Result Press CH 1 Channel 1 Control Menu appears Press
25. In LCR meter mode channel 1 measures the voltage across the component under test and channel 2 measures the current through it To measure the current channel 2 must be connected across an appropriate external shunt The easiest way to use the LCR meter is with the IAI impedance analyser interface See accessories that sits under the NumetriQ and provides 4 wire Kelvin clip connections to the component under test The IAI provides a choice of four shunts selectable from the front panel and buffers the signals to minimise the effects of stray Capacitance and inductance Measurements can be made without the IAI by simply connecting a series shunt The shunt chosen must be appropriate for the voltage the current and the frequency of operation There are three manual connection options shunt divider Zx low divider Zx high CH2 S GEN CH1 xX 14 1 PSM3750 user manual For shunt connection shown above the current is measured directly across the shunt using CH2 while the voltage across the Zx is measured by CH1 Notice that the positive inputs to both CH1 and CH2 are connected to the midpoint to minimise common mode loading effects Then Zx ZS x CH1 CH2 For divider Zx low connection shown above the total voltage is measured by CH1 and the voltage arising from the potential divider effect of Zs and Zx is measured by CH2 Notice that all the negative terminals are connec
26. N to adjust the amplitude use the OUT menu to change the size of the steps Press START and NumetriQ will start a frequency sweep over the specified range set in the SWEEP menu press TABLE to see the table of results GRAPH to see a graph of the results and REAL TIME to return to the real time data 2 4 PSM3750 user manual 3 Using the menus NumetriQ is a very versatile instrument with many configurable parameters These parameters are accessed from the front panel via a number of menus Each of the main menus may be accessed directly from a specific key ACQU data acquisition parameters such as speed and filtering SWEEP frequency sweep control TRIM generator trim control amplitude compression COMMS _ communications options RS232 etc ALARM control of audible alarm and analogue output OUT signal generator control CH1 channel 1 input control CH2 channel 2 input control and channel 3 SYS general system options such as phase convention keyboard beep etc MODE function control PROG recall store delete of non volatile programs Each menu starts with the currently set parameters visible but no cursor In this condition pressing the menu key again or the HOME key aborts the menu operation and reverts back to normal operation To select any parameter press the UP or DOWN key and a flashing box will move around the menu selecting each parameter In this condition the keys
27. SM3750 user manual 2 Getting started The NumetriQ is supplied ready to use it comes complete with an appropriate power lead and a set of test leads It is supplied calibrated and does not require anything to be done by the user before it can be put into service 2 1 Unpacking Inside the carton there should be the following items one NumetriQ unit one appropriate mains lead two or three voltage probes one set of output leads with croc clips one null modem cable to connect to a computer one USB to connect to a computer this manual one communications manual Having verified that the entire above list of contents is present it would be wise to verify that your NumetriQ operates correctly and has not been damaged in transit First verify that the voltage rating on the rear of the NumetriQ is appropriate for the supply then connect the mains cord to the inlet on the rear panel of the NumetriQ and the supply outlet Switch on the NumetriQ The display should illuminate with the model name and the firmware version for a few seconds while it performs some initial tests It should then default to the FRA display Note that the switch on message can be personalised see the User Data section under System Options 2 1 PSM3750 user manual The generator is off by default so the display may read some random values due to noise pick up Connect the Red and Black output leads to the 4mm output sockets on the rear of the NumetriQ and i
28. T test wind1 wind2 USER VECTOR parameter scaling VECTOR VECTOR SWEEP VERSION VRMS VRMS VRMS RMS VRMS SURGE WAVEFO type ZERO ZERO DELETE ZOOM level d1 d2 d3 d4 ZOOM single real data value single real data value range number range text over low ok data data data data data freq magl1 mag2 dB phase n lines of GAINPH data freq magl1 mag2 parameter n lines of TXA data 3 CR terminated text strings freq magl mag2 parameter phase a b n lines of VECTOR data datecode cpu dsp fpga boot RMS data followed by SURGE rmsl1 rms2 dc1 dc2 acl ac2 db1 db2 pk1 pk2 cf1 cf2 surgel surge2 level d1 d2 d3 d4 B 3 PSM3750 user manual calibration commands CALAPP CALCOM freq CALFIL index value CALFIL CALFRQ index freq CALFRQ CALI BR index value CALIBR CALOUT index value CALPHA index CALRES CALSAV password CALSNO serial number CALSTR string CALSTR six real data values seven real data values single integer data value string B 4 PSM3750 user manual Appendix C Available character set The following characters can be selected in text entry mode The table is to be read across then down eg starting at space and repeatedly pressing NEXT gives 4 amp etc j amp i 0 1 2 3 4 6 7 8 9 i lt gt A B C D E F G H J K L M N O P Q R S T U V W X Y i a b C d e g h i j k m n o p q r S t u V W x z
29. ad impedance minimises reflections at higher frequencies and improves transient response especially when driving long lengths of cable or transformers Part numbers 500 005 75 600Q adaptor with spacing 500 026 75 6009 adaptor with 3 4 spacing A 3 PSM3750 user manual CommVIEW PC software CommvlIEW is a self contained software program for a PC which facilitates communication with NumetriQ over RS232 CommVIEW allows strings to be sent and received between a PC and NumetriQ The strings can be viewed in a window and optionally stored in a file Data received from NumetriQ may be displayed in normal scientific notation with an identifying label Strings to be sent to NumetriQ can be stored in a script file and executed automatically The script file is created with any text editor and includes three types of lines interpreted by the first character on each line lines beginning with are sent to NumetriQ lines beginning with are commands for CommVI EW any other line is a comment The commands that are recognised beep sound the beeper on the PC label i string apply a label to data valuel i pause t wait for time t reply t wait time t for a reply For an example script file look at example scr on the CommVIEW release disc Other functions in CommvliEW save results results menu set COM port parameters configure menu firmware upgrade instrument menu read store user programs instrument me
30. al to use the NumetriQ generator when performing gain phase analysis there may be circumstances where this is impractical for example measuring across a transformer under load In this case turn off the NumetriQ generator OUT menu and the frequency reference for the analysis is measured from channel 1 Provided that the signal is clean enough for an accurate frequency measurement and for DFT analysis the frequency does need to be accurately known then the gain and phase can be measured reliably When using an external frequency reference there can be no sweep function 11 4 PSM3750 user manual 11 2 Quick start guide to Feedback Loop Analysis This section is aimed as a helpful guide to enable you to set up your PSM3750 with the aid of screenshots and instructions with respect to Feedback Loop Analysis Setting Input Channels to be used ACQUISITION CONTROL input 2 channels speed fast cycles 1 smoothing normal smoothing response auto reset phase reference channel 1 bandwidth auto advanced options gt Action Result Press ACQU Acquisition Control Menu appears Press J Flashing Red Box appears around the Input Channels selection Press gt Flashing Red Box appears around 2 channels 3 channels Press 4 Select 2 Channel Option Press ENTER 2 Channels have been selected as the Input Press HOME Flashing Red Box now disappears Press HOME Display returns to measurement
31. an be disabled via the SYSTEM OPTIONS menu The compensation for parasitic external values for example to compensate for the capacitance of the test leads when measuring capacitance is invoked manually by the ZERO key Refer to each function section for the function specific operations Any compensation values are stored along with the instrument configuration when a program is stored To restore operation without function specific compensation press ZERO then select the clear option 4 3 PSM3750 user manual 4 4 Alarm function NumetriQ has two independent alarms that can be read remotely or can generate an audible sound each of the alarms can be triggered by comparison to one or two thresholds Sound the alarm if the value exceeds a threshold Sound the alarm if the value is below a threshold Sound the alarm if the value is outside a window Sound the alarm if the value is inside a window Additionally one of the alarms can be used to generate a sound which varies linearly between thresholds The value to which each alarm is applied can be any of the measurements selected for zoom The alarm status is also available as a logic output on the parallel port To program an alarm first select the functions for the zoom up to four measurements can be selected for the display the alarm is applied to any of them then press ALARM to invoke the alarm Menu Select which of the zoom functions is to be used Select the type of alar
32. are expressed as dB relative to the fundamental 16 11 PSM3750 user manual 16 10 Longitudinal balance Longitudinal balance is a measure of the common mode rejection ratio CMRR of the transformer Longitudinal balance requires external circuitry to give the required accuracy a plug in module is available for the transformer analyser fixture TAFO1 with precision resistors and active buffers adjacent to the transformer pins to minimise stray effects As a figure of merit a higher value of longitudinal balance indicates a better transformer 16 12 PSM3750 user manual Transformer analyser specification Transformer analyser frequency 10uHz to 35MHz own generator 20mHz to 500kHz external source measurement type DFT analysis true rms as appropriate measurements turns ratio turns inductance leakage inductance ac resistance dc resistance interwinding capacitance insertion loss return loss harmonics thd longitudinal balance conditions auto or manual display numeric values table of sweep results graph of any measurement accuracy refer to other functions sweep Capability all ac functions sweep step rate 1 20s 1 3s or 2 5s approx 16 13 PSM3750 user manual Appendix A Accessories ACCESSORIES PSM3750 user manual Power meter adaptors The power meter adaptors allow easy and safe connection of the NumetriQ to a mains appliance under test to measure the power or harmonics The appliance
33. ate either from its own generator or more normally will use the frequency measured on channel 1 usually voltage The power meter measures the elementary values W V rms A rms V fundamental in phase and quadrature A fundamental in phase and quadrature V dc A dc V harmonic in phase and quadrature A harmonic in phase and quadrature frequency and derives the following values V amp A fundamental magnitude VA true and fundamental power factor true and fundamental fundamental W harmonic W phase shift 13 1 PSM3750 user manual When the integrator function is activated the following values are available Elapsed time in hours minutes and seconds Watt hours true and fundamental VA hours true and fundamental average power factor true and fundamental Ampere hours true and fundamental The power dissipated in a load subjected to a periodic voltage v 6 with a current flowing a 6 is given by 2T w 1 2x vid a d do 0 For a sampled signal the formula becomes i n 1 w 1 n gt vlil ali i 0 Where n is the number of samples for an integral number of complete cycles of the input waveform These are elementary definitions that are valid for all waveshapes NumetriQ computes the true watts value from the elementary definition for sampled data Formulae for the components at the fundamental frequency are given in the section on frequency response analysis formulae for the harmonic c
34. ay Newtons4th Ltd PSM3750 NumetriQ USER MANUAL Do not be hasty when making measurements NumetriQ is a precision instrument that provides you with the tools to make a wide variety of measurements accurately reliably and efficiently but good metrology practice must be observed Take time to read this manual and familiarise yourself with the features of the instrument in order to use it most effectively gt Be D DANGER OF ELECTRIC SHOCK Only qualified personnel should install this equipment after reading and understanding this user manual If in doubt consult your supplier RI SQUE D ELECTROCUTI ON L installation de cet quipement ne doit tre confi e qu un personnel qualifi ayant lu et compris le pr sent manuel d utilisation Dans le doute s adresser au fournisseur GEFAHR VON ELEKTRI SCHEM SCHOCK Nur entsprechend ausgebildetes Personal ist berechtigt diese Ausr stung nach dem Lesen und Verst ndnis dieses Anwendungshandbuches zu installieren Falls Sie Zweifel haben sollten wenden Sie sich bitte an Ihren Lieferanten RISCHIO DI SCARICHE ELETTRI CHE Solo personale qualificato pu installare questo strumento dopo la lettura e la comprensione di questo manuale Se esistono dubbiconsultate il vostro rivenditore PELI GRO DE DESCARGA EL CTRICA Solo personal cualificado debe instalar este instrumento despu s de la lectura y comprensi n de este manual de usuario En caso de duda con
35. components To save these system settings as default store the setup in program 1 so that they are reloaded on power on Pressing RIGHT from the SYSTEM OPTIONS menu selects the USER DATA screen see next section Pressing LEFT from first SYSTEM OPTIONS menu displays the serial number release versions and calibration date 6 2 PSM3750 user manual 6 1 User data NumetriQ can be personalised by entering up to 3 lines of user data as text see section on text entry User data is displayed every time that the instrument is switched on to identify the instrument The entered text may also be read over the communications to identify the instrument see USER Typical arrangement of the user data might be line 1 company name line 2 department or individual name line 3 unique identifying number eg asset number Any user data may be entered as required as the lines are treated purely as text and are not interpreted by NumetriQ at all For use in a production environment NumetriQ supports two modes of operation supervisor and user When supervisor mode is disabled the stored programs can only be recalled not changed In user mode NumetriQ will also not accept any commands which could change the calibration data After changing the user data or supervisor status execute store to save the data in non volatile memory 6 3 PSM3750 user manual 7 Measurement options 7 1 ACQU Acquisition options NumetriQ c
36. d the primary winding Connect the appropriate load resistance and CH2 differential input across the secondary When using the transformer analyser fixture the connections for insertion loss are made automatically by relays As the values of the load resistance RI and the source resistance Rs are used in the computation it is important that both values are entered via the MODE menu 16 10 PSM3750 user manual 16 9 Harmonics and distortion Harmonic distortion introduced by a signal transformer may be measured either at a single spot harmonic or as the thd computed from a series of harmonics The primary of the transformer is energised either by the output of NumetriQ or by external means and CH2 is connected across the secondary It is usual to measure harmonic distortion with the secondary loaded Specify the single harmonic or the maximum series harmonic via the SETUP menu NumetriQ analyses for up to 50 harmonics in real time using multiple DFTs refer to the chapter on gain phase analysis for the formulae for DFT analysis Each harmonic is individually phase referenced to the fundamental so that the in phase and quadrature components can be separately filtered As the harmonics are usually very small this technique is important to give adequate noise rejection The series harmonic data is combined to give the thd refer to the chapter on harmonic analysis for the thd formula The single harmonic and the thd
37. e first available result The flashing box is moved around the available results using the cursor keys UP DOWN LEFT and RIGHT Pressing the ENTER key selects the result for zoom and the box ceases to flash Further results up to four in total can then be selected using the cursor keys in the same way a Solid box remains around the already selected item and a new flashing box appears Having selected the desired results pressing the ZOOM key invokes the first zoom level pressing it again selects the higher level Pressing ZOOM steps back down one level each time Note that any of the parameters selected for the zoom function can be used as the input for the alarm monitoring and analogue output 4 1 PSM3750 user manual 4 2 Program store and recall There are 999 non volatile program locations where the settings for the entire instrument can be saved for recall at a later date Each of the 999 locations has an associated name of up to 20 characters that can be entered by the user to aid identification Program number 1 if not empty is loaded when the instrument is powered on so that NumetriQ can be set to a user defined state whenever it is switched on This is particularly useful to set system options such as phase convention etc If no settings have been stored in program 1 then the factory default settings are loaded program number 0 Program numbers 1 6 may be recalled with a single press of the function keys
38. e probe back to x1 and verify that the third harmonic reads the same Repeat the adjustment if necessary Select x10 on the other probe and adjust in the same way To verify the adjustment at higher frequency select the 25 harmonic for measurement The reading should be 4 00 0 5 in both x1 and x10 settings 9 5 PSM3750 user manual To adjust for the tolerance within the probes typically 1 the main inputs can be scaled and the secondary inputs can be adjusted Press OUT and set 1kHz sinewave 2V amplitude and press FRA to invoke frequency response analyser To adjust for tolerance within the probes connected to the main inputs With both probes set to xl check that the measured magnitudes are about the same Set the probe connected to CH1 to x10 and set the probe connected to CH2 to xl Press CH1 then TRIG the scaling factor for channel 1 will be automatically adjusted to a number about 10 Press HOME to exit the menu and observe that the readings for CH1 and CH2 are again about the same Set the probe connected to CH1 to x1 and set the probe connected to CH2 to x10 Press CH2 then TRIG the scaling factor for channel 2 will be automatically adjusted to a number about 10 Press HOME to exit the menu and observe that the readings for CH1 and CH2 are again about the same If you have a three channel instrument set the probe connected to CH1 to x1 and set the probe connected to CH2 to x10 Press CH2 then RIGHT to access the
39. econds The ZOOM function can be used to select up to four parameters from the display when in real time mode It has no function following a sweep 15 2 PSM3750 user manual Although it is most usual to use the NumetriQ generator when making harmonic measurements there may be circumstances where this is impractical for example measuring harmonic currents drawn from the mains In this case turn off the NumetriQ generator OUT menu and the frequency reference for the analysis is measured from channel 1 Provided that the signal is clean enough for an accurate frequency measurement and for DFT analysis the frequency does need to be accurately known then the measurements can be made reliably When using an external frequency reference there can be no sweep function 15 3 PSM3750 user manual 15 1 Harmonic analyser specification Harmonic analyser fundamental frequency harmonic frequency measurement type measurements max harmonic max input input ranges ranging input impedance magnitude accuracy sweep step rate Conditions 20mHz to 50MHz own generator 20mHz to 5MHz external source 10uHz to 1MHz multiple DFT analysis single harmonic differential thd thd by series of harmonics 100 10V peak 10V 3V 1V 300mMV High Voltage Attenuator 500V 300V 100V 30V 10V 3V 1V 300mv 100mV 30mV 10mV 3mV full auto up only or manual 1M 30pF exc leads 0 1 of fundamenta
40. egrate the total power in terms of heating effect choose magnitude If signed integration is selected then the rms current is given the sign of the power before integration The Ampere hours and Watt hours then reflect the power 13 3 PSM3750 user manual taken by the load less any power generated by the load such as during regenerative braking in battery systems 13 4 PSM3750 user manual 13 1 Power meter specification current input External shunt or Voltage CT display 5 digits measurement W VA PF V A Total Fundamental and Integrated Power Harmonics coupling AC DC AC lt 10VDC AC lt 500VDC frequency DC amp 10MHZ to 5MHz 5MHz to 50MHz fundamentals only ac coupling cut off 1 5Hz 3dB max input 500V peak input ranges 300mv 1lv 3v 10v High Voltage Attenuator 500V 300V 100V 30V 10V 3V 1V 300mV 100mV 30mV 10mV 3mV ranging Full Auto Up Only or Manual input impedance 1M Ohm accuracy ac 0 1 range 0 1 reading external shunt tolerance accuracy dc 0 2 range 0 2 reading CMRR typical 160dB 230V 50Hz 140dB 100V 1kHz 70dB 10V 1MHz time constant 0 2s 1 5s or 12s Conditions 232C 52C ambient temperature instrument allowed to warm up for 230 minutes sinewave power factor gt 0 7 slow speed normal filtering ac dc coupling autoranging or manual ranging 1 3 range tolerance of current shunt to be added 13 5 PSM3750 user manual 14 LCR meter
41. ep PAV parameter scaling PAV PAV SWEEP PHASE PHASE PHASE STREAM window PHCONV convention PHREF channel POWER integration type POWER WATTS POWER RMS POWER I NTEGR PPORT value PPORT PROGRAM function number PROGRAM freq magl1 mag2 dB phase n lines of GAINPH data freq magl mag2 hmagl1 hmag2 h1 h2 freq magl mag2 thd1 thd2 h1 h2 n lines of HARMON data mag1 1 61 mag2 2 62 1 line for each harmonic single integer data value freq magl mag2 impedance phase R L C series R L C parallel tans Q reactance freq magl mag2 impedance phase resistance reactance admittance phase conductance susceptance n lines of data freq QF tand impedance phase L C R freq QF tand admittance phase L C R freq magl mag2 parameter phase a b n lines of VECTOR data freq phase phase phase phase phase phase W W f VA VA f pf pf f Vdc W h freq rmsi1 rms2 dc1 dc2 fnd1 fnd2 61 62 Wh Wh f VAh VAN f pf pf f Ah Ah f t single integer data value CR terminated text string B 2 PSM3750 user manual RANGE ch ranging range RESOLU format REZERO SCALE channel factor SCALE channel SHUNT channel resistance SHUNT channel SINGLE on off SPEED speed window SSWEEP function number START STATUS channel STOP STREAM enable window STREAM disable STREAM SUSPEND on off TFA TFA TFA SWEEP TXA test fixture load source TXA TXA SWEEP TXTES
42. erator frequency The DDS is clocked at 210 MHz The DAC resolution is 14 bit The fine amplitude control is 10 bit 0 1 fsd The coarse amplitude control is 4 bit The maximum output level is 10V peak The maximum output current is 200mA peak The OV of the output is isolated from earth The output impedance is 50 The output frequency range is 10uHz to 50MHz The Sync output is TTL level at generator frequency attenuate offset filter 1 4 PSM3750 user manual 1 2 Voltage inputs Each input consists of a pair of ac or ac dc coupled high impedance buffers one for the high voltages and one for lower voltages The BNC safety connector and 4mm safety connectors are in parallel either connector may be used After the selectable heterodyning and filtering there is a series of gain stages leading to an A D converter The data from the A D is transmitted across an isolation barrier to the DSP Selection of the input gain the heterodyning and the sampling of the A D converter are under the control of the DSP There is an autozero switch at the front end for dc accuracy The maximum input is 500V peak The full scale of the lowest range is 3mV peak The input frequency range is dc to 50 MHz The A D converter resolution is 14 bit The A D sample rate is variable to 1M samples s input selection hetero isolation dyning barrier gt amp filtering high Z variable input buffers gain 1 5 P
43. esolution normal interface RS232 baud rate 19200 recall with program off screen print USB memory stick USB device ready Action Result Press COMMS Remote Settings Control Menu appears Press 4 5 TIMES Flashing Red Box appears around the Screen Print selection Press gt Flashing Red Box appears around disabled RS232 USB memory stick Press 4 Select USB memory stick only Press HOME USB memory stick mode has now been selected for screen prints Press HOME Display returns to measurement window The above description applies when the interface used is RS232 It may first be necessary to use the 4 amp keys to select the required interface before following the above steps The actual number of 4 key presses required depends on the interface selected 11 12 PSM3750 user manual Frequency response analyser specification Frequency response gain phase analyser frequency 10uHz to 50MHz own generator 20mHz to 5MHz external source max input 500V peak input ranges 300mV 1V 3V 10V lt High Voltage Attenuator 500V 3 oov 100V 30V 10V 3V 1V 300mV 100mV 30mV 10mV 3mV ranging full auto up only or manual input impedance 1M Ohm 30pF exc leads magnitude 0 075 range 0 075 reading accuracy 50uV lt 10kHz auto as above 0 0003 kHz wide as above 0 003 kHz gain accuracy 0 01 dB auto 0 01 dB 0 0001 dB kHz 0
44. frequency sweep is initiated by the START key and when completed the data can be viewed as a table or graphs Following a sweep on a control loop the gain and phase margins can be computed and displayed on the graph The window over which the measurements are computed is adjusted to give an integral number of cycles of the input waveform In real time mode the results from each window are passed through a digital filter equivalent to a first order RC low pass filter in sweep mode each result 11 3 PSM3750 user manual comprises a single window without any filtering unless repeat sweep is selected The top of the vertical axis for the graph is normally set to be the highest measured value during the sweep The bottom of the vertical axis is normally either set to the lowest measured value or the result of the highest value less 20dB decade of frequency The vertical axis can be fixed to a manual scale using the menus The ZOOM function can be used to select up to four parameters from the display when in real time mode It has no function following a sweep Following a sweep the GRAPH key selects between Graph of gain v frequency Graph of phase v frequency Graph of gain and phase v frequency If three channels are being used then the three graphs above are repeated for computation 2 as selected in the main FRA menu Pressing HOME or TRIG restarts the real time measurement at the selected frequency Although it is most usu
45. generator waveform delta frequency delta amplitude generator amplitude in dBm generator action at end of sweep Datalog parameters datalog memory type datalog interval General parameters program jump enable PLC interface enable D 2 83 95 96 99 100 101 102 106 107 108 109 116 117 118 119 121 122 123 124 125 126 127 130 131 132 133 PSM3750 user manual Power meter parameters integration type Streaming parameters data streaming data streaming window size Harmonic analyser parameters mode selected harmonic maximum harmonic computation LCR sweep zero parameters sweep compensation compensation start frequency compensation stop frequency compensation steps System parameters dBm level control step Message enable display sequence length units Transformer analyser parameters test fixture winding 1 winding 2 source impedance load impedance nominal number of turns TAF control parameters source winding load measure 1 measure 2 D 3 156 157 158 159 160 161 164 165 167 168 169 170 PSM3750 user manual LCR meter parameters computation series parallel sweep graph option active head control impedance lin log phase adjust value reference impedance reference type gain phase analyser parameters phase or delay time selection dB offset gain phase margin enable ratio selection System parameters minimum number of cycles delay time
46. ging is the most suitable option but some applications such as where transient events are occurring are more reliable with manual ranging Manual ranging or up only autoranging is essential for low frequency measurements For measuring signals that are biased on a dc level such as an amplifier operating on a single supply or the output of a dc PSU ac coupling can be used AC DC coupling is the normal option and should be used where possible A scaling factor can be entered for each channel for use with attenuators such as x10 oscilloscope probes A nominal value can be entered or the attenuation factor of the probe can be measured and the precise value entered The measured voltage will be displayed after multiplication by the scale factor The scale factor can be set automatically by pressing TRIG when in an input channel menu For example with a x10 oscilloscope probe on channel 1 input a x1 probe on channel 2 input and both 9 3 PSM3750 user manual probes connected to the same voltage press CH1 to invoke the input menu for channel 1 then press TRIG and the scale factor for channel 1 is computed so that channel 1 reads the same as channel 2 Note that when using external divider probes to increase the maximum input voltage it is important to use active probes if accurately measuring dc This because the dc input impedance is different from the ac input impedance When using passive probes the dc would read about 10 high If
47. if the direct load option is selected in the system menu see system options The instrument can be restored to the factory default settings at any time by recalling program number 0 The program menu is accessed using the PROG key The program location can be selected either by stepping through the program locations in turn to see the name or by entering the program number directly When storing a configuration in a program there will be a Slight pause of about 1 second if the program has previously been written or deleted The process will be very quick if the location has not been used When supervisor mode is disabled see system options programs can only be recalled not stored nor deleted to avoid accidental modification 4 2 PSM3750 user manual 4 3 Zero compensation There are 3 levels of zero compensation Trim out the dc offset in the input amplifier chain Measure any remaining offset and compensate Measure parasitic external values and compensate The trim of the dc offset in the input amplifier chain can be manually invoked at any time with the ZERO key or over the RS232 with the REZERO command The measurement of the remaining offset also happens when the offset is trimmed but is also repeated at regular intervals when using a measurement function that requires dc accuracy such as the rms voltmeter This is to compensate for any thermal drift in the amplifier chain This repeated autozero function c
48. ing a sweep the desired parameter must be selected The frequency points to be measured are specified with three parameters number of steps start frequency end frequency 12 2 PSM3750 user manual NumetriQ computes a multiplying factor that it applies to the start frequency for the specified number of steps Note that due to compound multiplication it is unlikely that the end frequency will be exactly that programmed The frequency sweep is initiated by the START key and when completed the data can be viewed as a table or graphs or printed out The window over which the measurements are computed is adjusted to give an integral number of cycles of the input waveform In real time mode the results from each window are passed through a digital filter equivalent to a first order RC low pass filter in sweep mode each result comprises a single window without any filtering The ZOOM function can be used to select up to four parameters from the display when in real time mode It has no function following a sweep Although it is most usual to use the NumetriQ generator when making Phase Angle Voltmeter measurements there may be circumstances where this is impractical for example measuring LVDT displacement under actual circuit conditions In this case turn off the NumetriQ generator OUT menu and the frequency reference for the analysis is measured from channel 1 Provided that the signal is clean enough for an accurate frequency
49. ion in the AUX menu to none 16 1 PSM3750 user manual The operating conditions for the component under test may be selected manually or for some tests such as turns ratio NumetriQ will automatically try to find appropriate conditions NumetriQ can operate either in real time mode at a single frequency where the measurements are filtered and updated on the display or it can sweep a range of frequencies and present the results as a table or graphs Before performing a sweep the required test must be selected The ZOOM function can be used to select up to four parameters from the display when in real time mode It has no function following a sweep Although it is most usual to use the NumetriQ generator when performing transformer analysis there may be circumstances where this is impractical for example measuring the turns ratio of a transformer under load In this case turn off the NumetriQ generator OUT menu and the frequency reference for the analysis is measured from channel 1 Provided that the signal is clean enough for an accurate frequency measurement and for DFT analysis the frequency does need to be accurately known then the measurements can be made reliably When using an external frequency reference there can be no sweep function 16 2 PSM3750 user manual 16 1 Turns ratio Turns ratio is computed from the real part of the complex ratio of CH2 divided by CH1 using DFT analysis at the fundamental
50. l 0 01mV accuracy of fundamental 1 20s 1 3s or 2 5s approx 232C 58C ambient temperature instrument allowed to warm up for 230 minutes ac dc coupling autoranging or manual ranging gt 1 3 range 15 4 PSM3750 user manual 16 Transformer analyser The transformer analyser mode allows a comprehensive set of measurements to be performed on a transformer at a single frequency or automatically swept over a range of frequencies The tests available are turns ratio inductance leakage inductance ac resistance and Q factor dc resistance interwinding capacitance magnetising current insertion loss return loss single harmonic distortion total harmonic distortion longitudinal balance The transformer analyser function is invoked and the test selected by the MODE key The easiest way to connect to the transformer in the various configurations for the different test is to use the transformer analyser fixture see accessories that connects to the NumetriQ BNC connectors via the BNC splitters and also to the NumetriQ extension port Using the fixture with appropriate source and load resistors the test configuration and winding selection is selectable from the front panel Active buffers within the fixture minimise the effects of stray capacitance and inductance For higher frequency operation or if the automatic fixture is not available make the connections manually with x10 oscilloscope probes set the fixture opt
51. m Set the upper limit if appropriate Set the lower limit if appropriate Select whether the alarm is to be latched Select whether the alarm sounder is enabled If the alarm latch is selected then the alarm will continue to sound even if the value returns to within the normal boundaries To clear the alarm press HOME The linear alarm option allows tests to be carried out even if it is not possible to see the display Pressing ZERO in the alarm menu sets the upper and lower threshold to 4 3 and 4 4 PSM3750 user manual 1 3 of the measured value respectively The repetition rate of the sounder then varies linearly as the value changes between these thresholds 4 5 PSM3750 user manual 4 5 Analogue output The analogue output is a 0 to 4V dc level that represents the selected measurement To program the analogue output first select the functions for the zoom up to four measurements can be selected for the display the alarm is applied to any one of them then press ALARM to invoke the alarm and analogue output menu Select which of the zoom functions is to be used Set the value for zero volts output Set the analog scaling factor The analog output level is computed as output voltage 4 scale measurement zero The output is updated whenever new data is available For maximum update speed select fast analogue output mode in the ACQU menu and enter a window value for 10ms or higher When START is pre
52. measurement and for DFT analysis the frequency does need to be accurately known then the measurements can be made reliably When using an external frequency reference there can be no sweep function 12 3 PSM3750 user manual 12 1 Phase angle voltmeter specification Phase angle voltmeter vector voltmeter frequency 10uHz to 50MHz own generator 20mHz to 5MHz external source measurement type DFT analysis and true rms measurements Magnitude Phase In Phase amp Quadrature components Tan In Phase Ratio LVDT diff LVDT ratio Rms Rms Ratio phase resolution 0 001 tan resolution 0 0001 other as FRA Conditions 232C 52C ambient temperature instrument allowed to warm up for 230 minutes ac dc coupling autoranging or manual ranging 1 3 range 12 4 PSM3750 user manual 13 Power meter The power meter measures the total power and fundamental power of the signal present at the input terminals to the bandwidth of the instrument gt 1MHz Above 5MHz only the fundamentals are measured One of the inputs must be configured as an external shunt input The external shunt may be a simple resistor or dedicated high frequency precision shunts are available as accessories Current transformers and clamps may be used if fitted with a suitable burden resistor For use at mains voltages a mains power adaptor incorporating voltage and current transformers is available The power meter will oper
53. measurement Alternatively the display can be forced to capacitance inductance or impedance Capacitance is displayed with tand inductance is displayed with Q factor and impedance is displayed in its resistive reactive form and as magnitude The phase of the impedance is displayed with all options The operating conditions for the component under test may be selected manually or NumetriQ will automatically try to find appropriate conditions When measuring large electrolytic capacitors it may be necessary to add an appropriate bias voltage to polarise the electrodes In this case it may be necessary to select ac coupling in the CH1 menu in order to reliably measure the small ac voltage present When measuring small inductance or capacitance it may be necessary to zero out the stray effects from the test connections Press ZERO to access the compensation menu For inductance connect together the test leads to a good short and select short circuit the message SHORT CIRCUIT ZERO SET will be displayed for capacitance disconnect the test leads and press ZERO the message OPEN CIRCUIT ZERO SET will be displayed To remove the zero press ZERO then press DELETE within 1 5s the message ZERO CLEARED will be displayed For repeated measurements under the same test conditions eg production testing of a batch of capacitors it is possible to compensate for the inherent phase shift of the connection jig Connect a k
54. ments of phase can be expressed in one of three conventional formats 180 to 180 commonly used in circuit analysis 0 to 360 commonly used in power applications 0 to 360 The measurement is exactly the same it is only the way that it is expressed that changes Blanking can be applied to a number of measurements so that zero is shown when the measurement is below a certain level This blanking can be disabled if desired Each key press is normally accompanied by an audible beep as well as the tactile click The beep can be disabled for quiet environments if the feel of the key is sufficient feedback Regular autozero measurements can be suppressed The 6 main function keys FRA PAV LCR RMS POWER HARM can be used to load stored configurations as a one touch way of configuring the instrument for specific applications This is particularly useful in a production 6 1 PSM3750 user manual environment where an operator has a small number of specific tests to perform Most data is displayed to 5 digits but for extra resolution 6 digits can be displayed when in ZOOM level 2 or 3 When using external shunts or attenuators the range can be shown either as the normal peak voltage or scaled by the shunt or attenuator factor Levels are usually expressed in volts but can be set and displayed in dBm which is a logarithmic scale referred to 1mW in 6009 often used when testing communications
55. nown reference component to the system enter the known phase shift of the component as the phase reference in the ZERO menu 14 4 PSM3750 user manual and select phase adjust NumetriQ then applies a compensating vector rotation to all subsequent measurements NumetriQ can operate either in real time mode at a single frequency where the measurements are filtered and updated on the display or it can sweep a range of frequencies and present the results as a table or graphs Before performing a sweep either series circuit or parallel circuit must be selected The frequency points to be measured are specified with three parameters number of steps start frequency end frequency NumetriQ computes a multiplying factor that it applies to the start frequency for the specified number of steps Note that due to compound multiplication it is unlikely that the end frequency will be exactly that programmed The frequency sweep is initiated by the START key and when completed the data can be viewed as a table or graphs or printed out The window over which the measurements are computed is adjusted to give an integral number of cycles of the input waveform In real time mode the results from each window are passed through a digital filter equivalent to a first order RC low pass filter in sweep mode each result comprises a single window without any filtering unless repeat sweep is selected Very good results can be obtained in
56. nput probes to the BNC on each of the input channels Connect the output to all the inputs by connecting the black clip on the output lead to the OV clip on each of the input probes and the red clip of the output lead to the input probes Note that this is easiest to do by connecting across a resistor any value above 1k Press the OUT key to invoke the output menu then press the UP key to select the output on off control then the RIGHT key to turn on the output by selecting on Exit the menu by pressing the ENTER button or the HOME button twice The display should now indicate a magnitude value of about 1 4V on all channels each of which should indicate the 3V range check that the gain reads 0 000dB 0 010dB and that the phase reads 0 000 0 010 In the event of any problem with this procedure please contact customer services at Newtons4th Ltd or your local authorised representative contact addresses and telephone numbers are given in the appendix at the back of this manual 2 2 PSM3750 user manual 2 2 Keyboard and controls The keyboard is divided into 5 blocks of keys display control 5 keys top left function keys 6 keys top right setup keys 12 keys lower left menu control keys 7 centre keys action keys 4 keys lower right In normal operation the cursor keys give one touch adjustment of various parameters such as generator amplitude and frequency without having to access the menu system The
57. nu A 4 PSM3750 user manual Appendix B Serial command summary command format CLS ESE value ESE ESR DN OPC RST SRE value SRE STB TRG TST WAI ABORT ACTRIM channel level tol ALARM latch sounder ALARM ALARME value ALARME ALARM 1 type data high low ALARM2 type data high low AMPLIT amplitude BANDWI type BEEP BLANKI on off threshold CONFIG parameter data CONFIG parameter COUPLI channel coupling COUPLI channel DATALO function interval DATALO start records DAV DAVER value DAVER FILTER type dynamics FRA FRA FRA SWEEP FREQUE frequency FSWEEP steps start end reply format single integer data value single integer data value company product serial no version Oorl single integer data value single integer data value single integer data value single integer data value single integer data value single integer or real data value single integer data value index time data one record per line single integer data value single integer data value freq magl1 mag2 dB phase n lines of GAINPH data B 1 PSM3750 user manual GAI NPH GAI NPH GAI NPH SWEEP HARMON scan para h hmax HARMON or HARMON SWEEP HARMON SERIES HOLD on off INPUT channel type INTYPE channel type INPUT channel KEYBOA value LCR conditions param head LCR or LCR SWEEP or LOWEFRE on off MODE type OFFSET offset OUTPUT type swe
58. ny comments or observations on the product please fill a copy of this form with as much detail as possible then fax or post it to us Alternatively send an e mail with your comments E 1 PSM3750 NUMETRIQ comments serial main release date number dsp release foga release boot release press SYS then LEFT your contact details comments detailed description of application or circumstances Please post or fax to Newtons4th Ltd
59. ome text as a title Text is entered by selecting one of 6 starting characters using the main function keys on the top right hand side of the keyboard FRA etc then stepping forwards or backwards through the alphabet with the UP and DOWN keys The starting letters are A FRA E PAV I LCR O RMS U POWER or space SCOPE Numbers can also be inserted using the number keys The UP and DOWN keys step forward and backward using the ASCII character definitions other printable characters such as or can be obtained by stepping on from the Space The available character set is given in the Appendix When entering alphabetic characters the ZOOM and ZOOM keys select upper and lower case respectively for the character preceding the cursor and the next characters to be entered The editing keys RIGHT LEFT DELETE and ENTER operate in the same way as for numeric entry 3 5 PSM3750 user manual 4 Special functions 4 1 Display zoom NumetriQ normally displays many results on the screen in a combination of small font size no zoom and up to 4 values in a larger font size first zoom level There is also an even larger font for up to 4 selected values second zoom level To set the data values for the larger font size first return to no zoom by pressing ZOOM up to three times if necessary Press ZOOM key to view the presently selected data and press DELETE to clear the selection A flashing box surrounds th
60. omes in 2 channel or 3 channel version The 3 channel version can be set to display just 2 channels if the third channel is not in use In normal acquisition mode the window over which the measurements are computed is adjusted to give an integral number of cycles of the input waveform The results from each window are passed through a digital filter equivalent to a first order RC low pass filter There are six pre set speed options very fast fast medium slow very slow and window that adjust the nominal size of the window and therefore the update rate and the time constant of the filter Greater stability is obtained at the slower speed at the expense of a slower update rate Note that the measurements have to be made over an integral number of cycles of the waveform so the window is extended to cover one or more complete cycles even if this is a longer period than the nominal update rate The minimum number of cycles to be measured in each window can be set from 1 to 100 There are two time constants for the filter normal or slow or the filter can be deselected The filter applies an auto reset function to give a fast dynamic response to a change of measurement this function can be deselected and the filter forced to operate with a fixed time constant for use with noisy signals 7 1 PSM3750 user manual The nominal values are speed update normal slow time rate time constant constant very fast 1 50s 0 1s 0 4s fas
61. omponents are given in the section on harmonic analysis The formulae for the derived results are VA Vims X Arms 13 2 PSM3750 user manual power factor Watts VA fundamental Watts Vreai X Areal Vquad X Aquad harmonic Watts VH reat X AHreai VHquaa X AHguad fundamental VA Vfund X Afund fund power factor Wuna VA und In power meter mode the UP and DOWN key do not adjust the amplitude but step the harmonic number The measurements are computed over rectangular windows with no gaps The processing power of the DSP allows the measurements to be made in real time without missing any samples In this way the measured power is a true value even if the signal is fluctuating The only occasion when data is missed is when an autozero measurement is requested this can be disabled in the SYSTEM OPTIONS menu The high linearity of NumetriQ allows real time measurements be made on waveforms with periodic bursts such as low standby power PSUs Use autorange up to find the range NumetriQ blanks the results when either of the measured rms signals are low compared to the full scale range This function can be disabled if desired in the SYSTEM menu The ZOOM function can be used to select any combination of up to four parameters from the display The integrator is started or reset by pressing the START key The Watt hour integration and the Ampere hour integration can be selected to be signed or magnitude To int
62. phase of each channel can be derived mag V a b 0 tan b3 a1 The relative gain and phase of the circuitry under test at that particular frequency is derived from the real and quadrature components by vector division vector gain a jb ch2 a jb ch1 gain magnitude vector gain phase tan b a vector gain The gain is usually quoted in dB dB 20 log o gain 11 2 PSM3750 user manual To look at differences in gain from a nominal value an offset gain can be applied either manually or by pressing ZERO Offset gain measured dB offset dB The filtering is applied to the real and quadrature components individually rather than the derived magnitude and phase values This gives superior results as any noise contribution to the components would have random phase and therefore would be reduced by filtering NumetriQ can operate either in real time mode at a single frequency where the gain and phase are filtered and updated on the display or it can sweep a range of frequencies and present the results as a table or graphs of gain and phase The frequency points to be measured are specified with three parameters number of steps start frequency end frequency NumetriQ computes a multiplying factor that it applies to the start frequency for the specified number of steps Note that due to compound multiplication it is unlikely that the end frequency will be exactly that programmed The
63. puted the true rms and the dc component the ac component can be derived from rms ac dc gt ac rms dc The ac component is also expressed in dB referred to 1mW into 6009 dBm dBm 20 log Vac Vref where Vref V 1mW x 6009 or 20 log lac Iref where Iref V 1mW 600Q The peak measurement is simply the value with the largest magnitude Positive and negative peaks are independently filtered then the result with the largest magnitude is taken as the peak value 10 2 PSM3750 user manual In order to measure surge conditions the maximum instantaneous peak value unfiltered is also recorded It is important that NumetriQ does not autorange while measuring surge either set the range to manual or repeat the test with ranging set to up only To reset the maximum press START Crest factor is derived from the peak and rms cf peak rms The rectified mean measurement is given by 27 mean 1 2n Iv o do 0 For a sampled signal the formula becomes i n 1 mean 1 n Sy vli i 0 The mean is then normalised to give the same value as rms for a pure sinewave Normalised mean mean x x 2V2 Form factor is derived from the normalised mean and rms ff mean rms The measurements are computed over rectangular windows with no gaps The processing power of the DSP allows the measurements to be made in real time without missing any samples In this way the measured rms is a tr
64. re press PROG and select memory type results 4 8 PSM3750 user manual 5 Using remote control NumetriQ is fitted with an RS232 USB serial and LAN communications port as standard and may have an IEEE488 GPIB interface fitted as an option All the interfaces use the same ASCII protocol with the exception of the end of line terminators Rx expects Tx sends RS232 carriage return carriage return USB line feed ignored and line feed LAN carriage return carriage return line feed ignored and line feed IEEE488 Carriage return or carriage return line feed or EOI with EOI All the functions of the NumetriQ can be programmed via either interface and results read back The commands are not case sensitive and white space characters are ignored e g tabs and spaces Replies from NumetriQ are always upper case delimited by commas without spaces Only the first six characters of any command are important any further characters will be ignored For example the command to set the generator frequency is FREQUE but the full word FREQUENCY may be sent as the redundant NCY at the end will be ignored Fields within a command are delimited by comma multiple commands can be sent on one line delimited with a semi colon eg AMPLIT 1 5 OUTPUT ON Mandatory commands specified in the EEE488 2 protocol have been implemented e g IDN RST and all 5 1 PSM3750 user manual commands tha
65. rmulae for DFT analysis CH2 is forced to be external shunt input enter the value of the external shunt as the source resistance via the SETUP menu To manually connect a transformer for inductance measurement connect an appropriate source resistance in series with the winding and connect the NumetriQ output across the series combination of the source resistance and winding Connect the CH1 input across the winding to measure the voltage and CH2 across the series resistance note that the polarity of external shunt input is the opposite of that for voltage Leave all other windings open To manually measure leakage inductance use the same set up as for inductance but short the other windings When using the transformer analyser fixture the connections for inductance or leakage inductance are made automatically by relays When measuring small inductance it may be necessary to zero out stray effects by replacing the winding with a good short and pressing ZERO The message ZERO SET will be displayed To remove the effect of the zero press ZERO followed DELETE within 1 5s and the message ZERO CLEARED will be displayed 16 4 PSM3750 user manual 16 3 AC resistance and Q factor AC resistance is measured the same way as inductance with CH1 monitoring the voltage across the winding and CH2 monitoring the current through it via the external shunt source resistance The Q factor measurement is an effec
66. ross it and the power that will be dissipated in it Connect CH1 directly across the primary winding using a pair of appropriate probes and CH2 across the series resistance with a second pair of probes note that the polarity of external shunt input is the opposite of that for voltage Ensure that all probes and the series resistance are appropriate for the voltage the current and the frequency of operation Energise the primary so that the voltage seen at the primary after the series resistance is the normal operating voltage 16 7 PSM3750 user manual 16 7 Return loss Return loss is a measure of impedance mismatch in signal transformers that are terminated with the design load resistance The secondary winding is terminated with the appropriate load resistance and the primary is energised via a source resistance that is equal to the resistance that should be reflected back from the secondary load resistance turns ratio The impedance looking into the primary is measured If z is the complex impedance measured at the primary and R is the source resistance then the return loss is given by return loss zZz R 2 R Return loss is usually expressed in dB 20 log z R z R dB As a figure of merit a higher value of return loss indicates a better transformer The circuit arrangement for return loss is the same as that for inductance measurement except that the secondary is terminated with the appropria
67. s Sinewave slow speed normal filtering ac dc coupling autoranging or manual ranging gt 1 3 range 10 5 PSM3750 user manual 11 Frequency response analyser NumetriQ measures the gain and phase of channel 2 relative to channel 1 using a discrete Fourier transform DFT algorithm at the fundamental frequency The DFT technique can measure phase as well as magnitude and is inherently good at rejecting noise it is much more reliable than measuring the rms at one point relative to another point The circuit can be characterised by computing the gain and phase at a number of points over a frequency range This gives results that show the transfer function of the circuit as a graph on the display The DFT analysis yields two components in phase and quadrature or a and b values from which the magnitude and phase can be derived Considering the components at the fundamental frequency The fundamental in phase and quadrature values of a periodic waveform v are given by 27 1 7 v cos o do 0 a1 2T bi Ux v 6 sin do 0 11 1 PSM3750 user manual For a sampled signal the formulae become i n 1 a 1 n DE v i cos 2xci n i 0 i n 1 b 1 n gt vlil sin 2zci n i 0 Where n is the number of samples for an integral number of complete cycles of the input waveform and c are the number of cycles Having computed the real and quadrature components the magnitude and
68. set 7 7 PSM3750 user manual 7 4 TRIM Trim function The trim function on NumetriQ is a powerful and versatile feature that allows closed loop control of the generator amplitude It allows a specific measurement from CH1 CH2 or CH3 if fitted and the generator output will be adjusted to maintain the measured voltage or current This allows the excitation level to be controlled over changing conditions such as a frequency sweep At each measurement point the measured level is checked against the specified level and tolerance if an adjustment is needed the data is discarded and a new measurement made at the new output level The user is alerted to the adjustment by an audible beep Particularly important in control loop analysis where it is sometimes referred to as amplitude compression it prevents the control loop being overdriven as the frequency changes It is also useful in a more general case where test levels are specified Note that when dBm mode level control is selected the trim level is entered as dBm but the tolerance remains a linear percentage of the actual voltage not the logarithmic dBm measure 7 8 PSM3750 user manual 8 Output control The output for the signal generator is digitally synthesised at an update rate of 150Msamples s With the output filtering this gives a good sinewave waveform even at 35MHz while preserving very accurate frequency control The output amplitude is controlled in 2
69. ssed the instrument enters a special mode where all non essential functions are suppressed including the display Press STOP to return to the normal display 4 6 PSM3750 user manual 4 6 Data hold When in real time display mode the data on the display can be held at any time by pressing the REAL TIME key When HOLD is activated a warning message is briefly displayed and the word HOLD appears in the top right hand corner of the display instead of the time Press the REAL TIME key again or the HOME key or START key to release HOLD in this case HOME and START do not have their normal functions When HOLD has been activated the DSP continues to sample compute and filter the results but the data is ignored by the CPU When HOLD is released the display is updated with the next available value from the DSP 4 7 PSM3750 user manual 4 7 Results store and recall There are 999 non volatile storage locations that can store either real time results or frequency sweeps Each location can store the sweep results for up to 50 points When storing a result a text string may be entered to help identify the data Each stored result also saves the instrument configuration along with the data same as program store recall so that the instrument is restored to the same settings when the result is recalled The results data may be restored manually or via communications for download to a PC To manually access the results data sto
70. stages a fine control with 10 bit resolution with coarse control with 5 steps This gives 10mV resolution at high output levels and 1mV resolution at low output levels The maximum output available from the generator is a function of frequency max frequency output level into 50Q MHz peak V rms V 1 7 5 5 5 5 3 5 10 3 2 15 2 1 4 20 1 5 1 25 1 2 0 8 30 1 0 7 35 0 75 0 5 40 0 6 0 5 50 0 4 0 25 An offset may be added to any output to bias the signal or to null out any dc present with a resolution of 10mV The LEFT and RIGHT keys adjust the frequency of the generator by a fixed increment stored via the STEP menu the UP and DOWN keys adjust the amplitude except for 8 1 PSM3750 user manual the harmonic analyser and power analyser where UP and DOWN step the selected harmonic The generator output may be set to be on off or dc only 8 2 PSM3750 user manual 8 1 Generator specifications accuracy frequency 0 05 amplitude 5 10 gt 50MHz accuracy with amplitude 1 lt 10MHz trim output impedance 509 2 output voltage 15V peak Offset 10V peak maximum waveforms sine square triangle sawtooth pulse and white noise frequency 10uHz to 50MHz output control 10mvV to 2mV steps Type direct digital synthesis update rate 210MHz DAC resolution 14 bit phase 48 bit accumulator 8 3 PSM3750 user manual 9 Input channels The two
71. sultar con su suministrador IMPORTANT SAFETY INSTRUCTI ONS This equipment is designed to comply with BSEN 61010 1 Safety requirements for electrical equipment for measurement control and laboratory use observe the following precautions e Ensure that the supply voltage agrees with the rating of the instrument printed on the back panel before connecting the mains cord to the supply e This appliance must be earthed Ensure that the instrument is powered from a properly grounded supply e The inputs and outputs must not be connected to common mode signals greater than 500V peak e The inputs must not be connected to signals greater than 500V peak e Keep the ventilation holes on the underneath and sides free from obstruction e Do not operate or store under conditions where condensation may occur or where conducting debris may enter the case e There are no user serviceable parts inside the instrument do not attempt to open the instrument refer service to the manufacturer or his appointed agent Note Newtons4th Ltd shall not be liable for any consequential damages losses costs or expenses arising from the use or misuse of this product however caused PSM3750 user manual DECLARATION OF CONFORMITY Manufacturer Newtons4th Ltd Address 30 Loughborough Rd Mountsorrel Loughborough Leics LE12 7AT We declare that the product Description Phase Sensitive Multimeter Product name NumetriQ Model PSM3750
72. t 1 12s 0 4s 1 5s medium 1 3s 1 5s 6s slow 2 55S 12s 48s very slow 10s 48s 192s There is alSo an option to set a specific size of the window to a value other than the preset options In order to synchronise to an integral number of cycles the window size is either reduced by up to 25 or increased as necessary The filter dynamics are usually set to auto reset where the filtering is reset in response to a significant change in data This speeds up the response of the instrument to changing conditions This function can be disabled so that the filtering has a fixed time constant which would have an exponential response to a step change The filter can also be reset by pressing TRIGGER When the generator is not used and so the measurement is synchronised to the input frequency measured on CH1 there is a low frequency option that extends the frequency measurement down to 20mHz This low frequency option also applies a digital filter which can be useful when measuring in a low frequency noisy environment In the case where there is very little signal on CH1 the reference for the phase can be set to another channel to give a more accurate measurement This does not change the phase result it only helps to reduce the uncertainty due to noise 7 2 PSM3750 user manual The bandwidth of the instrument usually set to auto can be forced to wide or low When not in auto selection heterodyning is disabled and
73. t expect a reply are terminated with a question mark NumetriQ maintains an error status byte consistent with the requirements of the IEEE488 2 protocol called the standard event status register that can be read by the mandatory command ESR See section 5 1 NumetriQ also maintains a status byte consistent with the requirements of the IEEE488 2 protocol that can be read either with the IEEE488 serial poll function or by the mandatory command STB Over RS232 or IEEE or LAN see section 5 2 The IEEE address defaults to 23 and can be changed via the COMMS menu The keyboard is disabled when the instrument is set to remote using the IEEE Press HOME to return to local RS232 data format is start bit 8 data bits no parity 1 stop bit Flow control is RTS CTS see section 5 2 baud rate is selectable via the COMMS menu When connecting to a PC use the supplied null modem cable A summary of the available commands is given in the Appendix Details of each command are given in the communication command manual Commands are executed in sequence except for two special characters that are immediately obeyed Control T 20 reset interface device clear Control U 21 warm restart To maintain compatibility with some communication systems there is an optional protocol 2 which requires a Space between the command and any arguments 5 2 PSM3750 user manual 5 1 Standard event status register
74. take on their secondary function such as numbers 0 9 multipliers n G etc Pressing the HOME key first time reverts to the opening state where the parameters are displayed but the cursor is 3 1 PSM3750 user manual hidden Pressing the HOME key at this point exits the menu sequence and reverts back to normal operation To abort the menu sequence press the HOME key twice There are three types of data entry selection from a list numeric text 3 2 PSM3750 user manual 3 1 Selection from a list This data type is used where there are only specific options available such as the output may be on or off the graph drawing algorithm may use dots or lines When the flashing cursor is highlighting the parameter the RIGHT key steps forward through the list and the LEFT key steps backwards through the list The number keys 0 9 step directly to that point in the list which provides a quick way to jump through long lists There is no need to press the ENTER key with this data type For example if the speed selection list comprises the options very slow item 0 slow item 1 medium item 2 fast item 3 window item 4 and the presently selected option is medium there are 3 ways to select window press RIGHT twice press LEFT three times press number 4 3 3 PSM3750 user manual 3 2 Numeric data entry Parameters such as frequency and offset are entered as real numbers freq
75. te load resistance As the value of the load source resistance R is used in the computation it is important that this value be entered via the MODE menu 16 8 PSM3750 user manual 16 8 Insertion loss Insertion loss is a measure of power loss due to impedance mismatch in signal transformers that are terminated with the design load resistance The secondary winding is terminated with the appropriate load resistance and the primary is energised via a source resistance that is equal to the resistance that should be reflected back from the secondary load resistance turns ratio The voltage energising the series resistance and primary winding is measured and the voltage on the secondary is measured If Rs is the source resistance the power into the transformer is computed as Win Vin 4 Rs If RI is the load resistance the power out is computed as Wout Vout RI Insertion loss then is given by Insertion loss Win Wout Vin Vout RI 4 Rs Insertion loss is usually expressed in dB 10 log Vin Vout RI 4 Rs dB As a figure of merit a lower value of insertion loss indicates a better transformer To manually connect a transformer for insertion loss measurement fit the appropriate source resistance in series with the primary winding then connect the NumetriQ 16 9 PSM3750 user manual output and CH1 differential input across the series combination of the source resistance an
76. ted together Then Zx Zs CH1 CH2 1 The connections for divider Zx high are the same as above but with Zx in the high arm of the potential divider and the shunt in the low arm Then Zx Zs x CH1 CH2 1 14 2 PSM3750 user manual NumetriQ measures the real and imaginary components at the fundamental frequency using DFT analysis as described in the section on gain phase analysis The frequency may be taken from its own generator or from the circuitry under test From the fundamental components of voltage a jb and those of the current c jd NumetriQ computes the complex impedance given by Z v i a jb c jd The components of the complex impedance are filtered independently to minimise the effects of noise which would have random phase and would therefore be filtered out The magnitude of the voltage and current are also computed From the complex impedance the following parameters can be derived ac resistance inductance capacitance impedance phase tans real imaginary Q factor imaginary real Values are displayed for both series and parallel configurations Optionally the values can be expressed as admittance conductance and susceptance instead of impedance resistance and reactance 14 3 PSM3750 user manual If the parameter option in LCR menu is set to auto NumetriQ will display capacitance or inductance according to the phase of the
77. tion for speed allows greater control of the measurement interval In this mode the display flashes DATALOG RUNNING and only shows the acquisition time The minimum datalog interval depends on the function but is typically 10ms 7 4 PSM3750 user manual Note that in all cases the measurement interval is necessarily adjusted to be an integral number of cycles of the measured waveform The datalog options are set up with the ACQU menu The datalog is started with the START key and stopped with the STOP key unless the store becomes full first The zero reference for the elapsed time is taken as the first data measurement after START The data can be viewed as a table or as individual graphs Pressing GRAPH steps the graph through the stored parameters If more than 250 records have been stored the graph can show the data for the whole period or pressing ZOOM redraws the graph to show 250 records about the cursor The cursor can be moved in single steps LEFT or RIGHT or large steps UP or DOWN Pressing UNZOOM shows the whole data gain Movements of the cursor are synchronised in both the TABLE and GRAPH views 7 5 PSM3750 user manual 7 3 SWEEP Frequency sweep options All ac measurements using the NumetriQ generator can be swept across a frequency range The start frequency stop frequency and number of steps up to 2000 can be specified The measurements are subjected to the same speed constraints set in the ACQU men
78. tive way of detecting a shorted turn either on a transformer or on a choke when using the transformer analyser fixture TAFO2 When using suitable conditions often very different from the normal operating conditions of the device under test the Q factor changes dramatically when a shorted turn is present 16 4 DC resistance DC resistance is measured with the same circuit arrangement as inductance and ac resistance but dc signals are used refer to the chapter on the rms voltmeter for the formulae for dc analysis 16 5 PSM3750 user manual 16 5 Interwinding capacitance The interwinding capacitance of a transformer is computed from the complex ratio of CH1 voltage across the transformer divided by CH2 current through the transformer using DFT analysis at the fundamental frequency refer to the chapter on gain phase analysis for the formulae for DFT analysis CH2 is forced to be external shunt input enter the value of the external shunt as the source resistance via the SETUP menu To manually connect a transformer for interwinding Capacitance measurement connect an appropriate source resistance in series with one winding and connect the NumetriQ output across the transformer from the series resistance to another winding Connect the CH1 input across the transformer from one winding to the other to measure the voltage across the windings and CH2 across the series resistance note that the polarity of external shunt inp
79. u but the filtering does not apply on each measurement point If continuous sweep is selected then the filtering is applied to each successive sweep At the end of a sweep the generator May be set to be on off or dc only The settings used are those in the normal generator menu The graph normally sets the y axis automatically to the extremes of the measurements or in FRA mode to 20dB decade of frequency but the axis can be fixed if required The graph of the second parameter usually phase can also be independently manually set A vertical marker can be placed on the graph to reference a specific frequency Each frequency point is an entirely new measurement and autoranging is restarted if enabled For the fastest possible sweeps select manual ranging As each frequency point is a new measurement filtering has no effect on a single sweep but fixed time filtering can be applied independently on each frequency point if repeat sweep in selected For maximum sweep speed particularly when using a large number of points there is a fast sweep mode which disables all non essential functions including the display during the sweep In this mode the display is blank except for a flashing message ACQUIRING SWEEP DATA until the full sweep has been completed when 7 6 PSM3750 user manual normal display functions are restored This mode is automatically selected when a user defined window of less than 100ms has been
80. ue value even if the signal is fluctuating The only occasion when data is missed is when an autozero 10 3 PSM3750 user manual measurement is requested this can be disabled in the SYSTEM OPTIONS menu if required The ZOOM function can be used to select any combination of up to four parameters from the display Note that the wideband nature of true rms measurements prevents the use of heterodyning so the frequency range of the measurement is limited to 5MHz To Minimise noise there is a 100kH7z filter applied by default To obtain the full bandwidth press ACQU highlight bandwidth and select wide 10 4 PSM3750 user manual 10 1 RMS voltmeter specification Channels 2 or 3 fully isolated Display 5 digits measurement true rms ac dc dBm peak cf surge Coupling ac or ac dc frequency DC to 5MHz heterodyning not available ac coupling cut off 1 5Hz 3dB max input 500V peak input ranges 300mV 1V 3V 10V High Voltage Attenuator 500V 300V 100V 30V 10V 3V 1V 300mV 100mV 30mV 10mV 3mV Ranging full auto up only or manual input impedance 1M 30pF exc leads accuracy ac 0 075 range 0 075 reading 0 1mV lt 1kHz above 0 003 kHz lt 5MHz accuracy dc 0 1 range 0 1 reading 0 5mV CMRR typical 160dB 230V 50Hz 140dB 100V 1kHz 70dB 10V 1MHz time constant 0 2s 1 5s or 12s Conditions 232C 58C ambient temperature instrument allowed to warm up for 230 minute
81. uency is an example of an unsigned parameter offset is an example of a signed parameter Real numbers are entered using the number keys multiplier keys decimal point key or key if signed value is permitted When the character string has been entered pressing the ENTER key sets the parameter to the new value Until the ENTER key is pressed pressing the HOME key aborts the data entry and restores the original number If a data value is entered that is beyond the valid limits for that parameter then a warning is issued and the parameter set as close to the requested value as possible For example the maximum amplitude of the NumetriQ generator is 10V peak if a value of 15V is entered a warning will be given and the amplitude set to the maximum of 10V When the parameter is first selected there is no character cursor visible in this condition a new number may be entered directly and will overwrite the existing number To edit a data value rather than overwrite it press the RIGHT key and a cursor will appear New characters are inserted at the cursor position as the keys are pressed or the character before the cursor position can be deleted with the DELETE key Data values are always shown in engineering notation to at least 5 digits 1 0000 999 99 and a multiplier 3 4 PSM3750 user manual 3 3 Text entry There are occasions where it is useful to enter a text string for example a non volatile program may have s
82. ut is the opposite of that for voltage When using the transformer analyser fixture the connections for interwinding capacitance are made automatically by relays When measuring small capacitance it may be necessary to zero out stray effects by disconnecting the transformer and pressing ZERO the message ZERO SET will be displayed The transformer analyser fixture TAFO1 has a stray capacitance of around 60pF that can be zeroed out this way To remove the effect of the zero press ZERO followed DELETE within 1 5s and the message ZERO CLEARED will be displayed 16 6 PSM3750 user manual 16 6 Magnetising current The magnetising current is the current drawn by the primary energised under normal operating conditions but without any secondary load It is typically measured on power transformers rather than signal transformers so although the transformer analyser fixture TAFO1 will select appropriate relays to make the measurement it is more common that a manual connection or a custom fixture would be used The magnetising current is measured as the true rms value refer to the chapter on the rms voltmeter for the formulae for rms analysis so it will include all distortion components To manually connect a transformer for magnetising current measurement connect an appropriate shunt in series with the primary When selecting the shunt bear in mind the current that it must pass the resulting voltage drop ac
83. window Depending on the actual measurements to be made it may also be necessary to Use the 4 key to step down the screen until the Flashing Red Box appears around the Speed Setting Then select the desired speed from the drop down list Press ENTER then HOME twice to return to the measurement window 11 5 PSM3750 user manual Setting the Amplitude and Output to On waveform amplitude control amplitude amplitude step size offset frequency step type frequency step size phase control output OUTPUT sinewave y 300 00m Fpk 1 1000 times 0 0000 F 16 000k Hz logarithmic 2 0000 times off on Action Press OUT Press 4 3 TIMES Press 300m Press ENTER Press 4 7 TIMES Press gt Press J Press ENTER Press HOME Press HOME Result Output Control Menu appears Flashing Red Box appears around the Amplitude Setting 300mv now appears in the Amplitude Option 300mv is selected as the Amplitude Flashing Red Box appears around the Output Mode Off On DC Only options appear on screen Select On option Output On is now selected Flashing Red Box will now disappear Display returns to measurement window Depending on the actual measurements to be made it may also be necessary to Use the 4 key to step down the screen until the Flashing Red Box appears around the Frequency Setting Then type in the desired frequency Press ENT
84. wing results can be derived magnitude a b phase tan b a tan amp b a in phase ratio a2 al LVDT diff scale a2 al LVDT ratio scale m1 m2 m1 m2 Where al and a2 are the in phase components and m1 and m2 are the magnitudes of the signals present at chl and ch2 respectively The parameter of interest is selected via the PAV or MODE menu The frequency and phase are always displayed 12 1 PSM3750 user manual A null meter display may be selected via the PAV menu to allow adjustment of a circuit for minimum phase or component The parameter on the display depends on the selected component parameter display null meter in phase in phase quadrature quadrature tan tan tan magnitude magnitude magnitude phase phase rms rms rms2 rms2 1 rms2 rms1 rms2 rms1 in phase ratio in phase ratio in phase ratio LVDT diff LVDT LVDT LVDT ratio LVDT LVDT The null meter may be manually ranged or will automatically range as the signal varies When manually ranging ZOOM and ZOOM adjust the range by a decade There is a phase offset option that applies a vector rotation of a user selectable phase shift to the CH2 input data NumetriQ can operate either in real time mode at a single frequency where the measurements are filtered and updated on the display or it can sweep a range of frequencies and present the results as a table or graphs Before perform
85. y aie cdi vias cea cedae Saka de cae 16 9 16 9 Harmonics and distortion cccccee cece eee seen eeene ees 16 11 16 10 Longitudinal balance kr eeneeees 16 12 VI APPENDICES Appendix A Appendix B Appendix C Appendix D Appendix E PSM3750 user manual Accessories Serial command summary Available character set Configurable parameters Contact details VII PSM3750 user manual 1 Introduction general principles of operation NumetriQ is a self contained test instrument with one output and two or three inputs which incorporates a suite of test functions NumetriQ has a wide bandwidth isolated generator output that can be used as signal generator for sine square triangle or sawtooth waveforms or true white noise A dc offset may be added to the signal generator output The output is fully isolated from earth to 600Vpk cat Il NumetriQ has two or three isolated high bandwidth voltage inputs which use direct digital analysis at low frequencies and a heterodyning technique to give high accuracy at high frequencies The inputs are fully isolated from each other and from earth to 600Vpk cat Il NumetriQ has two processors a DSP digital signal processor for data analysis a CPU central processing unit for control and display At the heart of the system is an FPGA field programmable gate array that interfaces the various elements see diagram below 1 1 PSM3750 user manual

PSM3750 - NumetriQ

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