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UTA Manual (ver. 2a)

1. 0 056 1 25 volts 51 42 klux per volt 64 3 klux Values in the box above are typical for full sun readings Those will be fine for many purposes But for low light conditions or for use with other sensors you may wish to set a different gain The switch settings inside the UTA can be manipulated with reference to the chart on page 6 There are a couple of guidelines for choosing the gain of stage 1 and stage 2 For the HOBO the gain of stage 2 should be x2 or greater S2 setting 14 or less not 15 Within that constraint it is best to use the highest gain possible on stage 1 switch S1 Note There is a 4 5 millisecond pause between the wake up and the first measurement Subsequently it takes up to four measurements spaced 14 5 millisecond apart then the power supply turns off and the HOBO goes back to sleep It may be best to connect the UTA HOBO to one of the later HOBO channels to allow more time for warm up ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com 15
2. 7 0 0 12 3 15 6 14 7 13 9 11 10 10 12 7 13 6 14 3 p 4 5 5 4 0 128 11 8 2 1 2 6 6 2 0 14 2 15 8 11 10 9 14 2 2 4 1 6 3 5 6 1 5 3 0 144 9 10 2 5 4 4 0 16 1 15 5 14 7 12 10 8 11 7 13 5 14 1 2 7 0 6 6 0 0 168 8 10 9 9 2 8 2 5 5 2 0 18 0 15 6 13 12 6 14 0 3 3 4 43 0 192 9 8 3 2 1 5 5 1 0 196 8 9 3 5 2 4 4 2 0 2 4 14 7 11 10 7 13 4 3 6 0 5 3 3 5 0 0 224 8 8 4 1 4 4 1 0 24 3 14 5 13 6 12 7 10 9 7 11 6 12 5 13 3 42 2 3 3 2 0 28 2 14 7 9 8 7 13 2 4 5 0 4 4 0 0 3 4 13 6 11 10 6 12 4 4 8 1 3 3 1 0 32 1 14 5 12 7 8 11 5 4 9 2 2 0 36 0 14 3 13 6 10 9 6 5 4 0 3 3 0 0 4 4 12 5 11 7 7 10 5 11 4 5 6 1 2 2 1 0 42 2 13 6 9 8 6 12 2 6 3 0 2 2 0 0 48 1 13 3 12 5 10 6 8 9 5 11 3 12 1 6 4 1 1 0 5 4 11 10 4 12 0 1 1 0 0 54 0 13 12 0 8 1 0 0 0 56 2 12 5 9 8 5 11 2 On x dE P q D S1i3 mi 44 E p Figure 2 Location of Switch 1 S1 and Switch 2 S2 on the UTA circuit board See Figure 3 for switch setting information ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com Figure 3a Settings for Switch 1 S1 d Glob d Glob d Eob
3. Check for evidence of water entry into the cabinet In regions of extreme humidity or precipitation it may be wise to place a dessicant such as silica gel inside the UTA s cabinet 2 Amplifier seems to be responding to light but the output seems too low or too high Things to check 2a Be sure you are using the correct multiplier in your calculations Refer to Table 2 and the switch block positions in the box The version of the UTA number should be printed on the top label or on the calibration label Be sure the UTA version matches with the version of the instruction manual 2b Place sensor in full unobstructed sunlight you should see a significant increase in output voltage Indoor lighting is much much weaker than full sunlight The standard amplification factors are designed to accommodate full tropical sunlight condi tions If you will be using your sensor in generally low light conditions say indoors in the arctic under a plant canopy or in deep water LI 192 or LI 193 you may wish to select a higher output voltage setting to bring the signal into the dynamic range of your data logger Please consult the LI COR literature and references or contact EME Systems for assistance 2c The power supply must be at least 2 volts greater than the desired full scale output voltage except the UTA HOBO ver sion which operates rail to rail 3 The amplifier output is unstable and readings fluctuate too much under constant lighting conditio
4. OO1O 1010 OLLO LLO OOO LOOL OLOL LOL OOLL LOLL OLLE JILL LL ras eL YL suonisod Z YOUMS O Ge oz SL OL 8 7A 9 S v Z L R suoljyisod L YOUMS JOA SI OA Cp URS SUIAIS 0000 UONIsod Yo IMs 0 JJOA S OA UlS SUIAIS T uonsod yoyms woy 33s IOIfI dure puodds 107 suonrsod yams opts doy V1 S JOA QT Q UILS SUTATS 0000 UONTsod Yyo IMs 0 VU SIOA p000 US SUIAIS QT TT UoTsod yoyms Wo 3gs Idur ISM OY 107 UOTISOd YAMS opts YOT SOSBdIDOP JOQUINU UOMISOd YYIMS SE SOSedIOUI UIeS Y 9 0U UO YOUMS o YOUMS 9721S JOIFI due puoses pue sxy 10 suowisod yoyms Iq d0 pue yo V SIOA 8 0 W1 S OA p000 Wo osuer duwor Jad s OA se passoidxa sues YLA 19A0 9 1qe1 Jo Apog UoT ISOd YOIMS JO UOTOUNY V sv URN BIquyL ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com Recalibrate the UTA The switches in the UTA select many possible values for the transconductance gain The gains are set by precision 0 1 accuracy metal film resistors The diagram below shows the location of the gain adjustment trimmer This trimmer can be adjusted to achieve the best possible gain on one particular switch setting The gain at other switch settings should then fall within 0 3 of the correct value but may not be as good as the switch position that has been trimmed The timmer can be adjusted as follows Use a precision current sink as the input signal for t
5. SZ model LI COR sensor while the UTA HOBO BNC is for use with the SA model LI COR sensors which have BNC connectors It should be noted that BNC connectors are not waterproof and should be used only in areas that are sheltered from water exposure For best water resistance use the SZ model LI COR sensors Additionally both the UTA HOBO and UTA HOBO BNC are available with a high precision high gain setting for use in low light level conditions e g indoor lighting studies or nD water studies using the LI 192 or LI 193 Please specify either UTA H OBO HG or UTA HOBO BNC HG for the high gain option The HOBO power supply is a small 3V lithium battery but despite its small size it is capable of operation for long periods of time between battery chang es Most of the time the HOBO is in a sleep mode wherein it requires little power At a specific time interval which you determine when you launch the HOBO the data logger wakes up turns on the external power supply red wire on the HOBO volt cable and records the data coming in from the sen sors The UTA is powered from the 2 5 volts provided by the HOBO during the measurement interval The UTA draws about the same current 125 uam ps as the Onset thermistor temperature probe so the UTA HOBO does not compromise the HOBO battery life In the UTA HOBO some components of the base model UTA have been replaced in order to meet the special low voltage low current and hi
6. amps for special purposes low light levels special supply voltages or micro power high speed operation dual output Some special options my also entail changes to gain or compensation components Standard gain op amp LT1490I 220u Vos 4nalb 200khz GBP r r i o 2V 44V 100ua power PSRR 98db LT1078I1 70uVos 6na Ib 200khz GBP output to Vd 0 8V 5V 44V 100ua power PSRR 114db Low offset high gain highest accuracy CAZ op amp LTC1051 1pVos 15pa Ib 2 5mhz GBP output to Vd 1 5V 5V 16V 2ma power PSRR 140db LTC2055HV Similar to the LTC1051 but operates on lower power supply voltage and current Higher speed TLV2462 500uVos 1na Ib 6 4mhz GBP r r i o 2 7V 5 5V Ima power PSRR 95db LTC6241 125uVos 1pA Ib 18mhz GBP r ro 2 8V 11V 3ma power PSRR 104dB low noise CMOS ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com 12 Appendix UTA HOBO The UTA HOBO is designed as a precision interface between LI COR light sensors Quantum PAR Pyranometer or Photometer and the Onset HOBO data logger LICOR sensors provide a small signal in the range of microamps whereas the HOBO inputs require a signal in the range of 0 2 5 volts The UTA HOBO provides this amplification and it also has features that allow it to operate directly from the HOBO power supply The UTA HOBO is manufactured in two models The base model UTA HOBO is for use with a
7. compensate for the effects of aging and degradation on the sensor ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com 9 Troubleshooting 1 UTA appears to be dead the output voltage is stuck at zero or full scale regardless of light level Things to check la Be sure protective red plastic cap has been removed from the top of the LI COR sensor 1b Check supply voltage and polarity at the red and black terminals of the UTA circuit board Ic Check the sensor polarity make sure that the center conductor on the sensor wire is connected to the white terminal and the outer shield wire is connected to the black terminal on the UTA input Id Check the screw terminal connections make sure all of the wires are clamped solidly in place The sensor wire should be clamped in the terminal not loose underneath it The center conductor of the sensor wire is delicate be sure it is not bro ken Je If you are testing the unit on a bench indoors you may have to move it very close to an artificial light source to get a response Light levels indoors are much much weaker than sunlight 1f Check that the gain selecting switches are completely pushed to one side or the other depending on the desired gain 1g Has there been a lightning strike in close proximity Although the UTA is protected against excess or reversed power supply voltages it can not be expected to survive catastrophic extremes Ih
8. micro station Onset Part H21 002 Use the 12 bit DC voltage input adapter Onset part S VIA CM14 to connect with the UTA HOBO You will need a 3 conductor cable to connect between the UTA HOBO and the voltage input adapter Make the following connections between the 3 terminal block on the UTA HOBO and the voltage input adapter terminal block red connects to TRIG SOURCE terminal block green connects to VOLTAGE INPUT and terminal block black connects to GROUND Once these connections have been made plug the voltage input adapter into the HOBO datalogger via the RJ11 telephone type connection ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com 13 Connections to Onset HOBO H8 U12 series common signal Insert cable through UTA HOBO gland nut and then Voltage Input Cable CABLE 2 5 STEREO screw down under terminal according to color black to black white to green ered to red UTA HOBO Insert LI COR sensor cable through gland nut then screw down under two input terminal according to color eshield to black ecenter conductor to white SZ model So LI COR sensor Figure 8 UTA to HOBO H8 U12 series Connections to Onset HOBO Weather Station and HOBO Micro Station To HOBO Weather Station or HOBO Micro Station 4 Onset 12 bit Voltage Input Adapter TRIG SOURCE VOLTAG
9. that if the LICOR sensor needs to be replaced or recalibrated then its attached UTA must also be recalibrated For example suppose you have a Quantum PAR sensor LI 190 and that its calibration tag states a multiplier of 187 5 uE m2s per pA Suppose you want to calibrate the UTA to have an output of exactly 4 0 volts when the solar input is 2000 uE m2s Note that the sensor output when the solar radiation is 2000pE m2s will be 10 667 microamps 2000 187 5 One way to do the calibration would be to apply a current of exactly 10 6667 microamps to the UTA input and then adjust the trimmer in the UTA to give an output of 4 0 volts It may be more convenient to use a standard current sink say 10 microamps and then set the output to 3 750 volts 4 10 10 667 The range of the trimmer may not be sufficient to reach some settings Please consult with EME Systems if you need special calibration for a UTA Alternatively a calibrated light source such as LI COR s 1800 02 Optical Radiation Calibrator can be used to match the sen sor to the UTA Place the sensor in the calibrator and adjust the first stage gain trimmer to match the desired voltage output Or you can use one recently calibrated LI xxx as your standard for calibrating others of the same type given a stable light source such as stable midday sun e LI COR recommends that all LI X XX series sensors be returned for re calibration every two years This will ensure proper calibration and
10. 2i EME SYSTEMS Universal Transconductance Amplifier Universal Voltage Output Amplifier for LI COR Sensors Amplifies LI COR sensor current to voltage logger level Version 2A User Manual Contents Overview amp specifications 1 Connect the input and output 2 Calculate the light level 3 Configure the amplifier gain switches 4 Recalibrate the UTA 9 Troubleshoot 10 Physical dimensions 11 UTA circuit operation 12 Appendix UTA HOBO special 13 Tables Figures and Equations table 1 UTA standard gain settings 3 table 2 switch positions vs gain required 6 table 3 gain vs switch positions 8 table 4 UTA HOBO standard gain settings 15 figure 1 UTA connections 2 figure 2 location of switches 6 figure 3 switch positions 7 figure 4 re calibration setup 9 figure 5 UTA enclosure physical dimensions 11 figure 6 UTA schematic diagram 12 figure 7 UTA to HOBO connection 13 figure 8 UTA to HOBO H8 U12 series 14 figure 9 UTA to HOBO Micro Station 14 equation 1 calculate light level from UTA output 3 equation 2 calculate UTA gain required gt rev 2a 20071204 ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com This page intentionally left blank ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com Universal Voltage Output Amplifier for LI COR Sensors Amplifies LI COR sensor current to volta
11. E INPUT GROUND Connect one side of a 3 conductor cable not included to the TRIG SOURCE VOLTAGE INPUT and GROUND connections on the Onset Voltage Input Adapter Insert the other end of the cable through the UTA HOBO gland nut and then Screw down under the 3 terminal block in the following manner Voltage Input Adapter TRIG SOURCE VOLTAGE INPUT UTA HOBO terminal RED GREEN BLACK Insert LI COR sensor cable through gland nut then screw down under two input terminal according to color eshield to black ecenter conductor to white SZ model faa LI COR sensor Figure 9 UTA to Micro Station and Weather Station ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com 14 Calculate the light level The external channels on the Onset HOBO data loggers record voltage When you acquire readings from the logger using the ONSET Boxcar software those readings will be in volts You will want to convert Volts to units of light measurement Drop the negative sign from the LI COR sensor multiplier when making this conversion UTA HOBO volt output sensor gain Light Level 1 equation 3 UTA HOBO transconductance gain Table 4 Gain Settings for UTA HOBO UTA HOBO 190 UTA HOBO 200 UTA HOBO 210 UTA Transconductance Gain V A 0 056 Note that LI 190 LI 191 LI 192 and LI 193 Quantum PAR sensors all
12. as this may cause the cover to deform or saddle which can compromise the seal Notes e Noise sources For long runs in the presence of halide lamps or other noise sources you should consider using shielded three wire cable for the power and signal connections between the logger and the UTA with the shield tied to common at one end only e Long wire runs The LI COR sensors come with 10 feet or 50 feet of cable The rest of the wire run from the UTA to the data logger or controller should be made with 22 gage or heavier wire The current flowing in the ground lead creates an error voltage that is added to the apparent output signal For example 1000 feet of 22 gage wire has a resistance of approxi mately 15 ohms The UTA power supply current of 0 0005 amp flowing in that wire would create a 7 5 millivolt offset On the 5 volt scale the error would be 0 0075 5 100 0 15 It is unlikely that you will be using such long wire runs How ever poor connections in the ground lead can provoke similar errors Be sure the ground lead is well secured The UCLC amplifier also offered by EME Systems is better suited to transmission of data as a current over long distances Calculate the light level In order to convert the UTA s output voltage into the appropriate units of light you will have to program your equipment to multiply the UTA output voltage times the LI COR calibration multiplier and divide by the UTA s transconductance gain vo
13. ase refer to the next section or contact EME Systems For example this would be called for if you need a different full scale voltage or if you are measuring a low light level 2 Note that LI 190 LI 191 LI 192 and LI 193 sensors all use roughly the same UTA transconductance gains The LI 192 and LI 193 have different calibration multipliers underwater and above water Configure the amplifier gain switches Most UTA users select from the standard 1 2 5 or 10 volt output settings However the UTA can be ordered or set by the end user to a gain setting to fit a particular requirement The gain settings that can be had through the switch settings are shown in table 2 and the manner of setting the switches in figures 2 and 3 Find the transconductance gain necessary for your application using the following equation desired UTA full scale output volts UTA ee On er are expected UTA input current from light sensor at full scale Equation 2 Once the transconductance gain has been calculated use Table 2 and Figure 3 to find a switch configuration that sets the actu al UTA gain close to the calculated gain Insert the transconductance gain found in Table 2 into equation to calculate the actual light level detected by your sensor Examples of custom UTA gain settings e Say you are working with a photometer in moderate light level conditions indoors where you expect to see top light levels around 10 klux Standar
14. d LEop 0 aS AD 4 aS AD 8 lS RAD 12 a aa el D oH D ob D eH D dsl p dq p qem D da D q Bop d E iop d Bop d Bop Hoa amp 1 q gt g VE 9 SEZ 13 doez no GG q p qe p q D em p Fii Lal D dee p d gt D BS D H qd op d b op d E loD qd lop ODIE ADX GY dy 4p ODIAN 2 6 10 14 ub D q BA D eb p q BE D b p dsb D B D dB D JE ioh 1 io d BoP d BoD GADI AN DLAN Hp a mo cay 3 Bi 7 qs DX 1 Ce BM 15 DX d p d i D eb p qe BH D Lal D dha p dB D SBE D Figure 3b Settings for Switch 2 S2 1 Mab 1 m q p qd isd 0 d E 4 d E eb 8 d Band 12 d D NADE GON NADE GN NDE GN NADE ON q0 D q0 CHAD NODE EY d E d E d E d E d 1 GEDEG 5 d E 9 d Hop 13 d Eep NDX ON NDE GN ADE GN MADE ON JOL p qo p JOL p dom D d eae d W d E d E 1 Bip q Y iep 1 Wip 1 P iep 2 6 10 14 dz ap dz p Jz ied dzb ep C Hp q0 1 D q0 q0 p d E d Be p d E d E q oD q oD q oD d cap 3 BZ 7 ZE 11 B44 15 LE dz ap dz ap dzb ep zh ied JOL D do p JoL p qo p Figure 3 Settings for Switch 1 S1 and Switch 2 S2 Use combinations of S1 and S2 settings as described in Table 2 to set desired gain of UTA ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com WJOA S JOA ule6 obeys puz SV Aseuig 0000 Ov Ge L000 0100 ywnl sioa urep obeys jsp Aseuig 0 L v S 9 Z 8 L100
15. d UTA gain settings will not sufficiently amplify such low light levels at a good resolution You have a photometer with a calibration multiplier of 2 78 klux per pA The controller you are using has analog input channels that allow 0 5 volts Using equation 2 the necessary transconductance gain is SV 2 78 klux pA 10 klux 1 39 V pA Looking at Table 2 we find that switch 1 index 2 switch 2 index 7 provides a transconductance gain of 1 400 V A which is close to the calculated gain Configure the switches to the correct positions then use equation 1 to calculate the actual light level from the observed UTA voltage output Light Level UTA volts sensor multiplier UTA transconductance gain from Table 2 Light Level UTA volts 2 78 klux per pA 1 400 Volts per uA ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com 4 e Say you are working with a quantum PAR sensor in a greenhouse with high intensity lighting where measured PAR can achieve levels of 2500 wE m s Standard UTA gain settings could saturate at such high light levels You have a quantum PAR sensor with a calibration multiplier of 138 31 wE m s per uA Your controller has analog input channels that allow 0 1 volt Using equation 2 the necessary transconductance gain is 1V 138 31 wE m2s per uA 2500 pE m s 0 0553 V pA Looking at Table 2 we find that switch 1 index 8 switch 2 index 14 provides a
16. ear wire coax core Switch Block S2 4 position Use to select desired 2nd stage gain Figure 1 UTA switch and connections diagram ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com 2 age you select for the UTA e g if using the 10 0 V F S setting your power supply must provide at least 11 volts or it must provide 6 volts power for 5 volt output or 5 volts power for a 1 to 4 volt output The UTA uses a dual opera tional amplifier integrated circuit that is capable of low offset voltage and operation on power supplies up to 28 volts For special gain settings we may employ a special op amp that has even lower offsets but will only operate from lower supply voltages If that is the case it will be noted on the amplifier calibration tag The UTA draws less than ImA of current making a battery a viable option for a power supply c The signal from the UTA should be taken between the green and black terminals Green is signal and black is common The green terminal should be connected to the signal input of your logger and the black terminal should be connected to common Note that the black terminal is common to both the power supply and signal line 3 Check all connections for proper polarity and be sure all wires are clamped solidly in place Replace the top cover on the enclosure and tighten the corner screws Take care not to over tighten the cover screws
17. el and a Sharpie marker for the new one ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com 5 Table 2 Switch positions as a function of gain required Note that some of the gain settings can be achieved with multiple switch combinations When this is the case it is usually preferable to choose a high gain low switch position in the first amplifier stage S1 Gain V A Possible Switch Setting Combinations S1 2 Gain V uA Possible Switch Setting Combinations S1 S2 0 004 14 15 0 6 3 11 4 10 6 7 7 6 9 4 10 3 0 008 13 15 14 14 0 64 1 12 5 8 11 1 0 012 12 15 14 13 0 7 2 11 4 9 8 4 10 2 0 016 11 15 13 14 14 12 0 72 0 12 3 10 9 3 11 0 0 02 10 15 14 11 0 8 1 11 4 8 5 7 7 5 10 1 0 024 9 15 12 14 13 13 14 10 0 84 2 10 3 9 8 3 9 2 0 028 8 15 14 9 0 9 0 11 6 6 10 0 0 032 11 14 13 12 14 8 0 96 1 10 3 8 9 1 0 036 12 13 0 98 2 9 8 2 0 04 7 15 10 14 13 11 14 11 1 4 7 7 4 0 048 9 14 11 13 12 12 13 10 1 08 0 10 9 0 0 056 8 14 13 9 1 12 1 9 2 8 8 1 0 06 6 15 10 13 12 11 14 6 1 2 3 7 5 6 6 5 7 3 0 064 11 12 13 8 1 26 0 9 8 0 0 072 9 13 12 10 1 28 1 8 0 08 5 15 7 14 10 12 11 11 13 7 14 5 1 4 2 7 7 2 0 084 8 13 12 9 1 44 0 8 0 096 9 12 11 10 12 8 1 5 4 6 6 4 0 1 4 15 10 11 14 4 1 6 1 7 5 5 7 1 0 112 8 12 11 9 1 8 0 7 3 6 6 3
18. er i o terminals Ordering example UTA 200 5 standard UTA configured for LI200 and 5 volts full scale output UTA BNC gx 0 56 UTA with BNC input connector gain set at 0 56 volts per microamp 1 LI 190 LI 191 LI 192 LI 193 LI 200 LI 210 and part designations are trademarks and the exclusive property of LI COR Biosciences Lincoln Nebraska www licor com 2 HOBO is a trademark of ONSET Computer Corporation Bourne MA U S A www onsetcomp com ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com 1 Connect the input and output The first step in using the UTA is to configure it for the LI COR sensor and output voltage scaling you wish to use You may have ordered your UTA pre configured for the appropriate sensor and full scale output voltage you need The preset value is marked on a label outside the UTA enclosure If you need to set or reset the gain factor please refer to pages 4 8 Configure the amplifier gain switches 1 UTA amplifiers are enclosed in a protective enclosure To gain access to the connection terminals and switch blocks remove the two corner screws using a standard screwdriver and lift up on the top There is a connection diagram under the cover 2 Refer to figure 1 The UTA has connections for the LI COR sensor input at one end of the circuit board and for the power supply and signal output at the other end a LIXXX SZ bare wire ter
19. ge logger level Version 2A The following instructions are provided to assist you in the installation and operation of your amplifier While we have made every effort to protect the amplifier from faults improper installation or misuse may result in incorrect readings or at worst failure of the amplifier Please read the manual in its entirety before connecting power to the UTA If you have questions about the UTA or any portion of this manual please contact EME Systems technical support e mail support emesystems com phone 510 848 5725 between the hours of 10 00 AM to 5 00 PM PST fax 510 848 5748 Overview and specifications The UTA is a special purpose amplifier that converts the microamp level current output of LI COR light sensors to a corre sponding signal voltage and provides a simple interface between LI COR sensors and voltage input data loggers chart recorders HVAC and greenhouse controls The UTA can be configured at EME Systems or by the end user for any one of a large number of gain settings through manipulation of two switch blocks The calibration tag provided by LI COR with each sensor in conjunction with the preset amplifier gain factor can be used to compute the light levels incident on the sensor with a high degree of accuracy Typical settings LI COR sensor Typical full sun response UTA output user selectable LI 190 191 192 193 PAR sensors 14 pA 2000 uE m s 1 2 5 10 Volts out 16 67pA inpu
20. gh speed requirements of the HOBO data loggers 1 12 bit DC voltage input adapter Onset Part S VIA CM14 required for UTA con nection to HOBO weather station H21 001 and HOBO micro station H21 002 dataloggers 2 Cable 2 5 Stereo Onset Part HOBO VOLT required for UTA connection to H8 and U12 series HOBO dataloggers Connect the UTA HOBO input and output Figure 7 UTA to HOBO connection A UTA serves as a link between a LI COR sensor and the Onset HOBO data logger The UTA amplifies the tiny current signal from the LI COR sensor and outputs a voltage compatible with the HOBO Figures 8 and 9 the UTA HOBO Connections Diagrams on the following page lay out connections between the UTA the LI COR sensor and the Onset HOBO data logger The connection between the UTA and the HOBO depends on the type of HOBO data logger you are using HOBO H8 U12 series Use the HOBO Voltage cable from EME Systems or the cable 2 5 volt from Onset Onset Part HOBO VOLT to connect he UTA HOBO to the HOBO The mini stereo plug connects to one of the input ports on the side of the HOBO data logger The other end of the cable end has three bare wires and goes through the gland nut on the side of the UTA nearest the three position terminal on the UTA circuit board The wires are screwed down under the terminals according to color code Red to Red White to Green Black to Black e HOBO weather station Onset Part H21 001 and HOBO
21. he amplifier and an accurate dig ital voltmeter to read the amplifier output voltage Set the output of the precision current sink to the desired the full scale sink current Adjust the first stage gain trimmer to give the corresponding full scale output For example to calibrate for a Quan tum PAR sensor we standardize with a 16 667 microamp input current and a 5 0 volt output voltage The adjustment range is 3 of the dip switch gain value Precision 4 digit DVM Vin UTA Circuit board Precision Floating Current Source foo Isink Gnd i o oO P Regulated DC power supply MA eoe Vou Gnd t p First stage gain trimmer adjustment Figure 4 UTA re calibration setup Notes e Each LICOR sensor has an individual calibration tag The standard calibration of the UTA requires that the calibration con stant be entered in software Alternatively a UTA can be calibrated to match an individual LI COR sensor For example 1000 watts meter2 input can give 1 00 volt output so the formula is simple W m volts 1000 That UTA then has to stay with that particular LI COR sensor In effect the calibration is done in the hardware rather than in the software This simpli fies the software particularly where a low resolution converter will be used or where calibration constants cannot be entered in software or where several light sensors must be interchangeable without reprogramming The disadvantage is
22. lts per Amp UTA output volts sensor multiplier Light Level W ____ Equation 1 UTA transconductance gain Each individual LI COR sensor has a distinct calibration multiplier You can find the multiplier for your particular sensor on the calibration tag on the cable of your LI COR sensor or the calibration certificate that came along with the sensor Drop the minus sign from the multiplier when carrying out the conversion calculation The gain factor for each UTA as shipped from EME Systems is printed on a calibration tag on the side of its enclosure Please refer to Table 2 to find the UTA transconductance gain for standard UTA output settings NOTE If you ordered a UTA HOBO please refer to the appendix section entitled Calculating light level from the UTA HOBO for conversion calculations Table 1 standard output transconductance gain in volts per microamp and switch setting Standard full scale output voltage 1 volt fs 2 volts fs 5 volts fs 10 volts fs LI 190 series 0 06 V A 0 12 V A 0 3 V pA 0 6 V uA LI COR sensor Quantum PAR S1 6 S2 15 S1 6 S2 14 S1 6 S2 11 S1 6 S2 7 LI 200 0 008 V A 0 016 V A 0 04 V uA 0 08 V uA Pyranometer S1 13 S2 15 S1 13 S2 14 S1 13 S2 11 S1 13 S2 7 LI 210 0 02 V uA 0 04 V A 0 1 V A 0 2 V uA Photometer S1 10 S2 15 S1 10 S2 14 S1 10 S2 11 S1 10 S2 7 ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www eme
23. mination LI COR part numbers ending with SZ are terminated with a stripped and tinned bare coaxial cable The LI COR cable may need to be enlarged in diameter to make a snug fit in the cable gland Use heat shrink or silicone tubing for this purpose On the inside of the box connect the inner conductor white or clear to the white colored terminal on the UTA board and connect the outer wire shield or tinned copper wire to the neighboring black terminal or LIXXX SA BNC termination LI COR part numbers ending with a SA are terminated with a BNC connector and should be used with the UTA BNC amplifier Simply align the connector with its mate on the outside of the UTA BNC and twist the two halves together The BNC connectors should lock together when they are properly seated b Connect the power supply from your data logger between the black common and red DC voltage terminals in the group of three The power supply voltage must be at least 5 volts and must be greater than the full scale output volt from LI xxx sensor T ree conductor cable Output calibration tag Mult 11 1 heatshrink tubing or silicone rubber tubing 3 32 i d 72 a d for larger diameter and snug fil irt garki rut Switch Block S1 4 position Use to select desired 1st stage gain Gnd Power supply Signal Out input and f Vcc signal output Licor Sae hro 5 24 vDo Sensor Input Cl
24. ns Things to check 3a Check all of the connections to the screw terminals Make sure all connections are tight and secure 3b Check for an AC component in the power supply voltage The power supply should be filtered direct current and should stay at least 2 volts above the full scale output voltage 3c Is the sensor close to a strong electromagnetic field such as a halide lamp or a refrigerator motor or other AC power equipment If so try to reroute the sensor cable or run the sensor cable inside a grounded metal conduit Avoid running the sensor cable in the same conduit as AC power lines 3d Occasionally oscillations can arise due to reactive loading on the signal cable Placing a 0 1uF capacitor between the signal terminal and the common terminal at your data logger input will usually suppress the oscillation ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com 10 UTA Polycarbonate Enclosure Physical Dimensions UTA standard UTA BNC 2 Holes 0 175 ID Screws Supplied Mounting Template not to scale Figure 5 UTA enclosure physical dimensions ver 2A 2007 EME Systems 2229 Fifth St Berkeley CA 94710 510 848 5725 fax 510 848 5748 www emesys com 11 UTA Schematic The information contained herein is provided as an aid to resolving que
25. stions about the amplifier and its application It is not meant for general distribution and remains the exclusive property of EME Systems UTA Universal Transconductance Amplifier Version 2 Version 2 Rev A UTA June 2006 UTA06g EME Systems 2229 Fifth St Berkeley CA 94710 tel 510 848 572 fax 510 848 5748 www emesystems com info emesystems com ae 40k 10k INPUT pa OUTPUT l 10k 40K Jok 10k 50k le Inf 2 5k Ot Volts 200 B 10k power 1k O Output LL103 2k Volts 40k 40k inf Q 1yf O Common Figure 6 UTA schematic diagram Switches are represented as dashed lines and are either open or closed to allow or short the parllel resistor s Switches on input stage select transconductance gains from 0 004 to 0 18 volts per microamp Switches on output stage select voltage gains from x1 to x45 Composite gains from 0 004 to 8 1 volts per microamp High gain settings use split T feedback Provision is made for a solder jumper on the bottom of the circuit board to boost the first or second stage gain by shorting the 10kQ resistors marked with in the split T networks Gains of 28 volts per microamp are possible for low light levels There is also provision on the circuit board for a voltage regulator for the power supply which would replace diode CD214 Special for Onset HOBO jumper 1a shorts diode Op amps for this circuit are socketed to allow field replacement and also to allow substitution of alternative op
26. sys com 3 Example calculations Example 1 UTA 190 1 amplify LI 190 PAR sensor output up to level of 0 1 volt full scale e UTA gain 1st column 1st row in Table 1 0 06 V uA 1 Volt full scale at 16 67 uA input from LI 190 e multiplier from LI 190 Quantum PAR sensor calibration tag or certificate 148 50 wE m2s per pA hypothetical e volts reading 0 836 Volts hypothetical gt light level UTA volts 148 50 0 06 0 836 volt 2475 uwE m2s per volt 2069 nE m2s Example 2 UTA 200 5 Amplify pyranometer output to 5 volts full scale e UTA gain 3rd column 2nd row in Table 1 0 04 V uA 5 Volts full scale at 125 uA input from LI 200 e multiplier from LI 200 Pyranometer sensor calibration tag or certificate 9 80 Wim2 per pA hypothetical e volts reading 3 80 Volts hypothetical gt light level UTA volts 9 80 0 04 3 80 volts 245 0 W m2 per volt 931 W m2 Example 3 UTA 210 10 Amplify photometer output to 10 volts full scale sunlight e UTA gain 4th column 3rd row in Table 1 0 2 V uA 10 Volts full scale at 50 uA input from LI 210 e multiplier from LI 210 Photometer calibration tag or certificate 2 63 klux uA hypothetical volts reading 6 25 Volts hypothetical gt light level UTA volts 2 63 0 2 6 25 volts 13 15 klux per volt 82 2 klux If you need units in footcandles 1 footcandle 10 764 lux Notes 1 If you need a different calibration setting ple
27. t LI 200 Pyranometer 100nA 1000 W m 1 2 5 10 Volts out 125A input LI 210 Photometer 40uA 100 klux 9290 fted 1 2 5 10 Volts out 50uA input These settings correspond to those of an earlier version of our UTA amplifier and are still our standard settings Many alternate gain settings are available from the table on page 6 amp 8 Those are useful for different full scale ranges of equip ment or for sensors under special lighting conditions Higher gain settings are useful for low light levels typical of photome ters indoors or PAR deep underwater A special UTA HOBO is available for use with ONSET HOBO data loggers appendix A Specifications standard configuration e Supply Voltage 5 24 VDC single supply at least 1 volt higher than full scale cat Special versions are available that have different power requiremeni e Supply Current less than ImA e Gain accuracy 0 2 on factory preset range 0 5 all ranges Voltage output in darkness lt 4 millivolts e Supply Voltage variation effect less than 0 01 per Volt e Response 2 milliseconds special versions available e Operating Temperature 30 C to 70 C e Tempco less than 0 01 per C e Output impedance 1000Q 1 e NEMA 4 gasketed white polycarbonate also available without enclosure 1 37 x 1 96 x 2 55 4 15 w glands PG7 gland nut or BNC at input PG7 gland nut at output RoHS compliant lead free e Phoenix beryllium copp
28. transconductance gain of 0 056 which is close to the calculated gain Configure the switches to the correct positions then use equation to figure out the actual light level from the observed UTA voltage out Light Level UTA volts sensor multiplier UTA transconductance gain from Table 3 Light Level UTA volts 138 31 uE m s per uA 0 056 Volts per uA Notes Choose a full scale output voltage less than or equal to your logger s input capability but not too much less For example if your logger has a full scale input range of 2 5 volts you should choose a setting that will never exceed 2 5 volts but will come close to that at its maximum e If you select too low a setting you will lose resolution and your logger will not register subtle changes and may fail to reg ister the lowest light levels of interest e If you select too high a setting the amplifier may overdrive or saturate the input circuit on your meter or even damage its inputs The highest light levels will all register as one value off scale e You may wish to purposely select a higher output setting to achieve greater sensitivity at low light levels This might be use ful in studies of indoor lighting or deep water studies with the LI192 or LI193 where full sun intensities will never be attained e The UTA power supply must always be greater than or equal to the full scale output voltage e You can use alcohol to rub off the old mark on the calibration lab
29. use the same transconductance gain Examples of light level calculations for UTA HOBO Below are examples that show the conversion from Volts to light level for different types of LI COR light sensors LI190 Quantum PAR sensor example e Switch settings S1 5 S2 14 gain 0 16 volts per microamp e UTA HOBO gain 0 16 volts per microamp 2 5 Volts full scale output at 15 625 amps input e multiplier from LI190 calibration tag or certificate 145 00 umoles m s per pamp hypothetical e Volts reading from HOBO 1 25 V hypothetical gt light level HOBO Volts 145 00 0 16 1 25 volts 906 25 umol m s per volt 1132 8 pmoles m 2s LI200 Pyranometer sensor example e Switch settings S1 14 S2 11 gain 0 02 volts per microamp e UTA HOBO gain 0 02 volts per microamp 2 5 volts full scale output at 125 amps input e multiplier from L1200 calibration tag or certificate 11 50 watts m per pamp hypothetical e volts reading from HOBO 1 25 V hypothetical gt light level HOBO volts 11 50 0 02 1 25 volts 575 0 watts m per volt 718 8 watts m2 LI210 Photometer sensor example e Switch settings S1 8 S2 14 gain 0 056 volts per microamp e UTA HOBO gain 0 056 volts per microamp 2 5 volts full scale output at 41 667 amps input e multiplier from LI210 calibration tag or certificate 2 88 klux per pamp hypothetical e volts reading from HOBO 1 25 V hypothetical gt light level HOBO volts 2 88

UTA Manual (ver. 2a)

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