DNA-AI-224 Product Manual - United Electronic Industries
Contents
1. NO 4 48 QBIKCH1 S 7 P CH1 28 P CH 1 49 QB120 CH 1 8 PS CH1 29 PS CH 1 50 QB CH 1 S CH 1 9 S CH1 30 S CH 1 51 QB350 CH 1 10 SHA CH 1 P CH 1 31 SHA CH 1 S CH 1 52 SHB CH 1 P CH 1 4 QB KKCH2 832 NO amp 53 P CH2 S 12 PS CH2 33 PS CH2 54 P CH2 C 13 QB350CH2 34 GND CH2 55 QB120 CH2 14 S CH2 35 S CH2 56 QB CH 2 S CH 2 15 SHA CH 2 P CH 2 36 SHA CH 2 S CH 2 57 NC 16 GNDCH3 37 SHB CH 2 P CH 2 58 QBIKCH3 SQ 17 P CH3 38 P CH3 59 QB120 CH 3 g 18 PS CH3 39 PS CH3 60 QB CH 3 S CH 3 amp 19 NC 40 QB350 CH 3 61 S CH3 O 20 SHA CH 3 P CH 3 41 SHA CH 3 S CH 3 62 S CH3 21 SHB CH 3 P CH 3 NC NC No Connection Do not use Rsvd Reserved for future use Figure 1 5 Pinout Diagram of the Al 224 Layer NOTE If you are using a DNA STP 62 accessory panel with the Al 224 please refer to Figure 1 9 on page 14 for a layout drawing of the board and to the Appendix for a description of the panel Copyright 2013 United Electronic Industries Inc Tel 508 921 4600 Date September 2013 Vers 4 6 DNx Al 224 Chap1x fm www ueidaq com 1 8 1 Full Bridge Gauge Connections Full Bridge Strain Gauge Rg Copyright 2013 United Electronic Industries Inc DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 11 Introduction Figure 1 6 shows the connections between a full bridge strain gauge and the2. Vers 4 6 DNx Al 224 Chap1x fm DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter1 14 Introduction 1 8 4 Connecting It is recommended to use a DNA STP 62 screw terminal panel accessory for Bridge making connections to bridge completion resistors Layout of a DNA STP 62 is Completion shown in Figure 1 9 below and Figure A 1 on page 21 of the Appendix Resistors DB 62 female g JT3 20 position 62 pin connector terminal block JT2 20 position terminal block JT1 20 position terminal block J2 5 position terminal block 62 to J2 42 toJ2 21 toJ2 61 toJT1 41 toJT1 20 toJT1 0 22 0 55 0 20 5 SHIELD 60 toT 40 to JT1 19 to JT1 o1 0 13 0 41 4 GND 59 toJT1 39 to JT 18 toJT1 O43 0 34 O61 362 58 toJT1 38 to JT 17 toJT1 0 23 O54 O19 2 42 57 toJT1 37 to JT1 16 toJT1 o 2 o2 0 40 1421 56 toJT1 36 toJT1 15 toJT1 Oo 44 O33 O 60 55 to JT2 35 toJT1 14 toJT1 O 24 053 0 18 54 to JT2 34 toJT2 13 toJT2 o3 o 0 39 53 to JT2 33 to
3. are also provided to allow the connection of external shunt calibration resistors if desired The on board shunt calibration system is limited Finding actual resistor net works that would provide this functionality and maintain the required accuracy over this wide temperature range within the space available on the DNx Al 224 is not possible However it is relatively straightforward to fit a resistance mea surement system that performs resistance measurements at a level suitable for high accuracy shunt calibration In the Al 224 a 200kohm nominal 256 tap dig ital potentiometer is used as internal shunt calibrator allowing characterization of a load cell Note that the digital shunt can be switched to connect to either side of the bridge tension or compression as shown in Figure 1 6 through Figure 1 8 The digital potentiometer is then adjusted to bring the bridge into balance with the shunt resistor in parallel with the strain gauge To perform shunt calibration with the DNx Al 224 the user selects the shunt resistance desired as well as whether compression or tension simulation is desired The DNx Al 224 driver software then selects the shunt resistor to the setting closest to the desired value The resolution of the shunt resistance selec tion is approximately 1 1 kOhm The DNx Al 224 software then performs an automatic measurement of the selected shunt resistor and returns the measured resistance within 0 0296 of the reading This measure
4. pChan SetExcitationFrequency 60 0 The AC excitation function is supported by hardware but not supported in soft ware release 4 6 Contact UEI for more information of how to get this function 2 3 3 Offset Nulling Offset Nulling is turned on using the channel object enable Offset Nulling pChan gt EnableOffsetNulling true You then need to set the offset nulling setting which will program the offset nulling DAC set Offset Nulling 0 0 for auto pChan SetOffsetNullingSetting 0 0 Using a setting value of 0 0 will automatically calculate the setting value that will balance the bridge make sure your strain gauge or load cell is not under stress Start the session read a few data points and verify that they are close to 0 0 Stop the session and read the setting value that was calculated to balance your bridge get Offset Nulling setting auto calculated by setting to 0 0 offsetNullSetting pChan GetOffsetNullingSetting Store that value and program it using SetOffsetNullingSetting each time you start a strain measurement session If you change anything in your bridge wir ing you will need to re do the offset nulling setting calculation 2 4 Configuring You can configure the Al 224 to run in simple mode point by point or high the Timing throughput buffered mode ACB mode or high responsiveness DMAP mode In simple mode the delay between samples is determined by software on the host com
5. shunt resistance Figure B 2 Strain Gauge with Shunt Resistance R Added After replacing R4 with R4 Rs R4 Rs in Equation 1 the voltage output of the bridge when the shunt calibration resistor is enabled is R4 Eq 2 Vout Vex UAR S LUE R3 R4 R1 R2 R4 Rs The voltage output change after enabling the shunt resistor is AVout Vouts Vout R4 Eq 3 AVout Vex RATRs R4 R34 R4 R3 R4 R4 Rs In most applications all branches of the Wheatstone bridge use the same resistance Standard values for Rg are 120 350 and 1000 Ohms After setting R1 R2 R3 Rg Equation 3 becomes R Eq 4 AVout V 8 g om 4Rs 2Rg Copyright 2013 i Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industries Inc Date September 2013 DNx Al 224 AppxB fm DNA DNR AI 224 High Speed Strain Gauge Input Board Appendix B 24 Shunt Calibration Support in Framework Shunting branch R3 instead of R4 to simulate a tensile load gives Rg Eq 5 AVout Ve IE CORN Now that we know how to calculate the theoretical offset on the Wheatstone bridge output when one of the branch resistances is changed with a known value we can compare it with the measured value and get the Gain Adjustment Factor Eq 6 Gaf AVoutCalculated AVoutMeasured Multiplying each measured values by the Gain Adjustment Factor gives us calibrated measurements ac USC RU M E M M m 4dM J
6. 0 19 2 42 L toJT1 0 2 0 12 0 40 1421 aon 0 44 0 33 60 toJT2 0 24 0 53 o 18 ME 03 oj O39 to JT2 0 45 0 32 0 59 l to JT2 O25 0 52 0 17 5T toJT2 o 4 0 10 0 38 50 to JT2 0 46 0 31 0 58 to JT2 O26 0 51 0 16 48 to JT3 O 5 o 9 0 37 47 to JT3 0 47 0 30 O 57 46 to JT3 0 27 50 015 45 to JT3 O 6 Ols 036 44 to JT3 O 48 029 O 56 3 to JT3 0 28 0 49 0 14 O GND 0 7 0 35 toJ2 toJT1 toJT2 toJT3 Figure A 1 Pinout and photo of DNA STP 62 screw terminal panel Copyright 2013 Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industries Inc Date September 2013 DNx Al 224 AppxA fm DNA DNR AI 224 High Speed Strain Gauge Input Board Appendix B 22 Shunt Calibration Support in Framework Appendix B Shunt Calibration Support in Framework B 1 Introduction Strain gauges and load cell measurements are typically based on the Wheatstone bridge which allows the measurement of the very small resistance changes that characterize strain gauges The values measured from a Wheatstone bridge are very sensitive to the resistance of its branches and can be attenuated by lead resistances Shunt calibration is used to compensate for the loss of sensitivity caused by leadwire resistances The strain gauge is desensitized Shunt calibration is the action of simulating a load on one of the branches of a Wheatstone bridge with a resistor of a known value
7. 29 For all output data rates the clock source varies from gt 150 000 to 300 000Hz Copyright 2013 Tel 508 921 4600 www ueidag com Vers 4 6 United Electronic Industries Inc Date September 2013 DNx Al 224 Chap3 fm DNA DNR AI 224 High Speed Strain Gauge Input Board Appendix A 21 Appendix A A Accessories The following cables and STP boards are available for the Al 224 layer DNA CBL 62 This is a 62 conductor round shielded cable with 62 pin male D sub connectors on both ends It is made with round heavy shielded cable 2 5 ft 75 cm long weight of 9 49 ounces or 269 grams up to 10ft 305cm and 20ft 610cm DNA STP 62 The STP 62 is a Screw Terminal Panel with three 20 position terminal blocks JT1 JT2 and JT3 plus one 3 position terminal block J2 The dimensions of the STP 62 board are 4w x 3 8d x1 2h inch or 10 2 x 9 7 x 3 cm with standoffs The weight of the STP 62 board is 3 89 ounces or 110 grams cte female JT3 20 position JT2 20 position JT1 20 position J2 5 position pin connector terminal block terminal block terminal block terminal block toJ2 42 BE EE JTi 0 22 055 O 20 5 SHIELD 60 tori o1 O13 O 4l 4 GND to JT1 0 43 0 34 0 61 3 62 M O23 0 54
8. Al 224 board Excitation voltage is applied between P and P and sensed between PS and PS Since no bridge completion is required with a full bridge sensor the DAC input to MUX1 is not used in this configuration External Shunt sb z Calibration PS O P O M R5K x PGA gt 1 5K Sos M 5K U PGA X 2 e SHB Resistor Al 224 Board Figure 1 6 Full Bridge Strain Gauge Circuit As part of the internal shunt calibration function the Al 224 board measures the voltage drop across a precision 5K resistor and computes the exact value of the digital shunt with 02 accuracy This value is reported to the software The shunt may be adjusted from 6 7K to 170K ohms Note that the shunt may be switched to either side of the bridge tension or compression Tel 508 921 4600 Date September 2013 www ueidaq com Vers 4 6 DNx Al 224 Chap1x fm 1 8 2 Half Bridge Gauge Connections DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 12 Introduction Figure 1 7 shows the connections between a half bridge strain gauge and the Al 224 board Excitation voltage is applied between P and P and sensed between PS and PS As shown in the diagram below the board uses a pro grammable DAC to simulate the other half of the bridge The DAC output is fed to the PGA input and the S point is connected to the PGA input of the first dif ferentia
9. Disclaimer WARNING DO NOT USE PRODUCTS SOLD BY UNITED ELECTRONIC INDUSTRIES INC AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS Products sold by United Electronic Industries Inc are not authorized for use as critical components in life support devices or systems A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness Any attempt to purchase any United Electronic Industries Inc product for that purpose is null and void and United Electronic Industries Inc accepts no liability whatsoever in contract tort or otherwise whether or not resulting from our or our employees negligence or failure to detect an improper purchase Specifications in this document are subject to change without notice Check with UEI for current status DNA DNR AI 224 High Speed Strain Gauge Input Board Contents Table of Contents Chapter 1 Introduction 0 0 ee 1 1 1 Organization of Manual 1 0 2 00 00 do kesre tsa NRS nn 1 1 2 The Al 224 Interface Board 1 0 ees 3 1 3 Features uela Gade re ue AUR das AE ba bed bea vada 4 1 4 Specification e ma V ob roe ER ARRA EURO EHE RRR eile Bw Do AR ula 5 1 5 Device Architecture 0 00 cc ele 8 1 6 Auto Null Adjustment 0 0 0 0 0 eens 9 1 7 n dlCatOls i osc eae eA ee PA eed DER armi Te Vd dae
10. H 2 X Copyright 2013 l Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industries Inc Date September 2013 DNx AI 224 AppxB fm A A D Converters 4 B Block Diagram 8 C Cable s 21 Configuring the Resource String 16 Connectors and Wiring 10 Conventions 2 Creating a Session 16 H High Level API 16 Isolation 3 J Jumper Settings 5 DNA DNR AI 224 High Speed Strain Gauge Input Board Index L Low level API 20 O Organization 1 S Screw Terminal Panels 21 Setting Operating Parameters 4 Shunt Calibration 22 Specifications 5 Support 11 Support email support Queidaq com ii Support FTP Site ftp ftp ueidaq com ii Support Web Site www ueidaq com ii Copyright 2013 Tel 508 921 4600 Date September 2013 United Electronic Industries Inc www ueidaq com Vers 4 6 DNx Al 224 ManuallX fm
11. JT2 12 to JT2 0 45 0 32 O59 52 toJT2 32 toJT2 11 to JT2 0 25 052 0 17 51 toJT2 31 to JT2 10 to JT2 o4 Oo 10 038 50 toJT2 30 toJT2 9 toJT2 0 46 0 31 0 58 49 to JT2 29 toJT2 8 toJT2 0 26 0 51 0 16 48 to JT3 28 to JT3 7 toJT2 o 5 o9 0 37 47 to JT3 27 to JT3 6 toJT3 0 47 0 30 0 57 AG to JT3 26 to JT3 5 toJT3 0 27 O50 0 15 45 to JT3 25 to JT3 4 toJT3 o6 08 036 44 toJT3 24 to JT3 3 toJT3 0 48 029 O56 43 to JT3 23 to JT3 2 toJT3 O28 Q 49 0 14 22 to JT3 1 to JT3 O GND 0 7 0 35 zi i i 1 SHIELD IO on 424 09 090e609000600000 0 0 0 0 9 0712 eecccococccccococcc 62 43 toJ2 toJT1 to JT2 to JT3 Figure 1 9 Layout of DNA STP 62 Screw Terminal Panel For quarter bridge measurement using a DNA STP 62 screw terminal panel install connection leads as shown in Table 1 3 on page 14 The leads will con nect the bridge completion resistors between P and the 3 wire remote junction point Sj Refer to Figure 1 8 on page 13 for a drawing of the circuit The figure also shows the setup for using the bridge completion DAC Refer to Figure 1 7 on page 12 for a half bridge setup that does not use bridge completion resistors Table 1 3 Lead Connections for Quarter Bridge Circuits Bridge Competion Leads Required for 3 wire Quarter Bridge Measurement Resistor Ch 0 Lead Ch 1 Lead Ch 2 Lead Ch 3 Lead 120 ohm Sij to 24 S to 49 Sij to 55 Sij to 59 350 ohm Sj to 45 Sj to 51 Sj to 13 Sij to 40 1000 ohm Sj to 1 Sj to 48
12. Level API Be mindful of your gain setting Note that when reading any of the channels in point by point mode the hardware actively keeps the data just below the gain limit When the gain is set too high the output will appear as an inverted approx imate of the actual signal scaled down under the gain limit Try a lower gain value or begin with one To program the excitation circuitry you need to configure the channel list using the session object method CreateAIVExChannel instead of CreateAlChan nel This method also gives you the ability to select the bridge configuration you want and to select whether or not you wish to obtain the acquired data already scaled in mV V acquired voltage divided by actual excitation voltage as follows Configure channels 0 1 to use a gain of 128 in differential mode program the excitation to 10V and turn on scaling with excitation aiSession CreateAIVExChannel pdna 192 168 100 2 Dev0 Ai0 1 Ov Se ew UeiSensorFullBridge ORE OR true UeiAIChannelInputModeDifferential CreateAlVExChannel only gives access to a few of the channel properties You can access advanced channel properties such as offset nulling shunt cal ibration bridge completion using channel objects associated with each channel configured in the resource string You will first need to get a pointer to the channel object for wich you wish to change properties using the index of the channel in the channel lis
13. PGA input and the S point is connected to the PGA input of the first differential PGA amplifier To complete the bridge three bridge completion resistors 120 350 and 1K ohm resistors are mounted on the Al 224 board between S and P To select one of the three resistors to serve as R3 for a particular application install a jumper connector between applicable terminals on the I O connector or STP board PS P External Roz R5K Shunt Cal sHA Sis pese Resistor Ix PGA got 1 R5K S e o gt S es M TS gt u PGA Leadwire to Srj remote junction SHB X or bridge completion 2 External Shunt Cal Bridge Resistor ROM Completion sb Resistors SHB For 2 wire connections see Table 1 2 on page 14 See Table 1 2 on page 14 for terminal numbers for each channel Al 224 Board Figure 1 8 3 Wire Quarter Bridge Strain Gauge Circuit As part of the internal shunt calibration function the Al 224 board measures the voltage drop across a precision 5K resistor and computes the exact value of the digital shunt with 05 accuracy This value is reported to the software The shunt may be adjusted from 6 7K to 170k ohms Note that the shunt may be switched to either side of the bridge tension or compression Tel 508 921 4600 Date September 2013 Copyright 2013 United Electronic Industries Inc www ueidaq com
14. Sj to 11 Sij to 58 NOTE For 2 wire quarter bridge circuit connect bridge completion leadwire to S instead of S Pin 3 for Ch0 Pin 50 for Ch1 Pin 56 for Ch2 Pin 60 for Ch3 1 8 5 Raw Analog Input with Excitation The Al 224 can be used for traditional analog input with the added bonus of an optional continous analog excitation output This mode is useful for applications where strain gages are not used or where bridge completion is either not necessary or already provided by an external circuit Copyright 2013 United Electronic Industries Inc Tel 508 921 4600 Date September 2013 Vers 4 6 DNx Al 224 Chap1x fm www ueidaq com DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 15 Introduction 1 9 Shunt Shunt calibration of a strain gauge bridge is performed by placing a known resis Calibration tor across one leg of the measurement Wheatstone bridge The purpose of this technique is to simulate the effect of applying a specific physical load to the bridge sensor without actually doing so Placing the shunt across the excitation and the signal leg of the bridge can be used for tension shunt calibration placing it across the excitation and the alternate leg of the bridge can be used for com pression shunt calibration The DNx Al 224 provides built in shunt calibration resistors that can be set in tension or compression in the range from 6 7 kOhm to 170 kOhm in about 1 1kOhm increments Terminals
15. TX or QNX and graphical applications such as LabVIEW MATLAB DASYLab and any application supporting ActiveX or OPC 1 Board is capable of providing AC excitation but this feature is not software supported in the current release qua m Ru uo nec mc c M T H amp PI N HR P e s c Ym s La c J rr s Y a d s ili Copyright 2013 Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industries Inc Date September 2013 DNx Al 224 Chap1x fm DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 Introduction 1 4 Specification The technical specification for the DNx Al 224 board are listed in Table 1 1 Table 1 1 DNx Al 224 Technical Specifications Number of channels 4 simultaneously sampled Configuration Full Half or Quarter bridge Resolution 18 bit Input ranges tSee table below Sample rate 100 kilosamples per second max Accuracy Integral non linearity 0 0015 Offset error 25 C G 2 0 0005 typical see graphs on next page Gain error 25 C G 2 0 003 typical see graphs on next page Offset drift per C 2ppm typical 10ppm max Gain drift per C Overall error 2ppm typical 10ppm max 250 uV Bridge resistance 120 350 or 1000 Ohm Anti aliasing filter Automatic 72 dB minim
16. ZN United Electronic wy Industries The High Performance Alternative DNx AI 224 User Manual 4 Channel High Speed Strain Gauge Analog Input Layer for the PowerDNA Cube and PowerDNR RACKtangle Release 4 6 September 2013 PN Man DNx AI 224 913 Copyright 1998 2013 United Electronic Industries Inc All rights reserved No part of this publication may be reproduced stored in a retrieval system or transmitted in any form by any means electronic mechanical by photocopying recording or otherwise without prior written permission Information furnished in this manual is believed to be accurate and reliable However no responsibility is assumed for its use or for any infringement of patents or other rights of third parties that may result from its use All product names listed are trademarks or trade names of their respective companies See the UEI website for complete terms and conditions of sale http www ueidaq com cms terms and conditions Contacting United Electronic Industries Mailing Address 27 Renmar Avenue Walpole MA 02081 U S A For a list of our distributors and partners in the US and around the world please see http www ueidaq com partners Support Telephone 508 921 4600 Fax 508 668 2350 Also see the FAQs and online Live Help feature on our web site Internet Support Support supportQueidag com Web Site www ueidag com FTP Site ftp ftp ueidaq com Product
17. a ER ee a 9 1 8 Layer Connectors and Wiring llielleee eh 10 1 8 1 Full Bridge Gauge Connections llle 11 1 8 2 Half Bridge Gauge Connections 0 0 ee 12 1 8 3 Quarter Bridge Gauge Connections 0 000 eee eee 13 1 8 4 Connecting Bridge Completion Resistors 2 2020005 14 1 8 5 Raw Analog Input with Excitation lees 14 1 9 Shunt Calibration 00 RR n 15 Chapter 2 Programming with the High Level API lseeeeennnnne 16 2 1 Creating a Session 0 0 00 eee 16 2 2 Configuring the Resource String llle 16 2 3 Configuring for Input llle I n 16 2 3 1 Bridge Completion 0 000 nh 17 2 3 2 AC Excitation 202 uu pur eme kel en erbe eels ea E e pe ee 18 2 3 3 Offset NUMA Gis cem ridet nen rote bea t sec eas entm vr EERE 18 24 Configuring the Timing cser sessa srasaroy adinan DESS ANE a RI eh 18 2 5 Read Data ess EE dae AE Sak ene eee E EE 19 2 6 Cleaning up the Session 0 00 eae 19 Chapter 3 Programming with the Low level API 0c e eee eee eee eee 20 Copyright 2013 Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industries Inc Date September 2013 DNx Al 224 ManualTOC fm Figures List of Figures 1 1 Offset error and RMS noise vs gain sssssssssene enne 6 1 2 Noise amplitude at various sampling rates sssssseseeeeeeeeee 7 1 3 Block Diagram of t
18. agram of the architecture of the Al 224 layer Architecture 2x 5V DC DC sw controlled 10V PHExc P Q 10V s P Ex P Bridge compl Bridge 5 Null Sg amp 5 9 o o 2 8 Tt 8 m D o a D PS z z O F8 a o N D S _ I o zr gt S 9 s S lt Sie 18 bit o T 9 2 S ire UE iid 2x gain X E eo o 2 i 5 E ds ue amp 512 tap E Shunt FIRFilters a Calibration Channel 1 of 4 Figure 1 3 Block Diagram of the Al 224 Layer Each quarter bridge strain gauge sensor is combined with bridge completion resistors mounted on the Al 224 board or an applicable STP board to form a half bridge which is combined with a DAC voltage to simulate a full bridge or equivalent Similarly each half bridge sensor is combined with a DAC voltage to simulate a full bridge The output of each full bridge sensor is sensed directly by the Al 224 without completion resistors or DAC except for excitation Refer to Figure 1 6 to Figure 1 10 for the various connection circuits used Excitation for the strain gauge is supplied from a 16 bit quad DAC under pro gram control The DAC can produce two excitation voltages either static DC or dynamic AC in a range of 10 volts dual outputs As an option these two voltages may be configured to produce a single voltage o
19. and comparing the measured value to the calculated ideal value The ratio between the ideal value and the measured value is called Gain Adjustment Factor It should be very close to 1 Multiplying the measurement value by the gain adjustment factor compensates for the loss of sensitivity introduced by the lead resistances in a four wire gauge B 2 Theory Load cell and strain gauge measurement are normally done through a Wheatstone bridge For load cells the Wheatstone bridge is built into the cell For strain gauges the bridge is part of the wiring Figure B 1 Strain Gauge Bridge Vex is the excitation voltage applied to the bridge by the instrument Vout is the output voltage measured by the instrument The formula to calculate Vout knowing Vey is Eq 1 Vout vex RA IRE R3 R4 RI R Simulating a load is usually done by adding a larger resistance in parallel with one of the branches To simulate a compression load we need to add a shunt resistance to Rg and to simulate a tension load we need to add a resistance to R3 Copyright 2013 Tel 508 921 4600 www ueidag com Vers 4 6 United Electronic Industries Inc Date September 2013 DNx AI 224 AppxB fm DNA DNR AI 224 High Speed Strain Gauge Input Board Appendix B 23 Shunt Calibration Support in Framework The following figure assumes that all branch resistances are equal to Rg strain gauge resistance and that the R4 branch was shunted with a resistance Rs
20. bject create a session object for input CUeiSession aiSession 2 2 Configuring UeiDaq Framework uses resource strings to select which device subsystem the Resource and channels to use within a session The resource string syntax is similar to a device class gt lt IP address gt lt Device Id Subsystem Channel list For PowerDNA and RACKtangle the device class is pdna For example the following resource string selects analog input lines 0 1 2 3 on device 1 at IP address 192 168 100 2 pdna 192 168 100 2 Dev1 Ai0 3 as a range or as a list pdna 192 168 100 2 Dev1 Ai0 1 2 3 2 3 Configuring The AI 224 can be configured for strain gauge input for Input The gain to be applied on each channel is specified with low and high input lim its For example the Al 224 available gains are 1 2 4 8 16 32 64 128 256 and the maximum input range is the full 20V differential span To select a gain of 128 you must specify input limits of 0 1V 0 1V Configure channels 0 1 to use gain 128 in differential mode aiSession CreateAIChannel pdna 192 168 100 2 Dev0 Ai0 1 Orly 0 1 UeiAIChannelInputModeDifferential p DHb a a a a a L ANG o AaB x ET Copyright 2013 i Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industries Inc Date September 2013 DNx Al 224 Chap2x fm DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 2 17 Programming with the High
21. d value is then used by the application s calibration routine as the shunt resistance switched in The board also provides for connection of two user supplied external shunt cal ibration resistors Refer to Figure 1 5 for the pinout Note that the calibration resistors connect to terminals SHA P and SHA S or SHA S and SHB P Fig Rg Ry Ag Figure 1 10 Shunt Calibration NOTE Refer to Appendix B for a more detailed description of the shunt calibration method used in the Al 224 modules Copyright 2013 l Tel 508 921 4600 www ueidag com Vers 4 6 Unfied Electronic Indusiries ine Date September 2013 DNx Al 224 Chap1x fm DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 2 16 Programming with the High Level API Chapter 2 Programming with the High Level API This section describes how to control the DNx Al 224 using the UeiDaq Frame work High Level API UeiDaq Framework is object oriented and its objects can be manipulated in the same manner from different development environments such as Visual C Visual Basic or LabVIEW The following section focuses on the C API but the concept is the same no matter what programming language you use Please refer to the UeiDaq Framework User Manual for more information on use of other programming languages 2 4 Creating a The Session object controls all operations on your PowerDNx device Therefore Session the first task is to create a session o
22. e designed to highlight quick ways to get the job done or to reveal good ideas you might not discover on your own NOTE Notes alert you to important information CAUTION Caution advises you of precautions to take to avoid injury data loss and damage to your boards or a system crash Text formatted in bold typeface generally represents text that should be entered verbatim For instance it can represent a command as in the following example You can instruct users how to run setup using a command such as setup exe Text formatted in ixed typeface generally represents source code or other text that should be entered verbadim into the source code initialization or other file Examples of Manual Conventions Before plugging any I O connector into the Cube or RACKtangle be sure to remove power from all field wiring Failure to do so may cause severe damage to the equipment Usage of Terms Throughout this manual the term Cube refers to either a PowerDNA Cube product or to a PowerDNR RACKtangle rack mounted system whichever is applicable The term DNR is a specific reference to the RACKtangle DNA to the PowerDNA I O Cube and DNx to refer to both Copyright 2013 f Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industries Inc Date September 2013 DNx Al 224 Chap1x fm DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 3 Introduction 1 2 The Al 224 The DNA AI 224 and DNR AI 224 are hi
23. f 10 Volts The AC excitation mode is not software supported in the current release of the Al 224 Copyright 2013 f Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industies In Date September 2013 DNx Al 224 Chap1x fm DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 Introduction The analog measurement voltages from each strain gauge bridge as shown in Figure 1 3 are fed through input multiplexers to a programmable gain amplifier They may be strain measurements or miscellaneous voltage signals used to compute values of resistors in various internal circuits then passed to the A D converter The A D converter one per channel is a successive approximation 18 bit device which also performs signal averaging for further noise reduction The output is then passed to two cascaded FIR filters which among other func tions performs additional anti aliasing digital filtering The combination of the low pass analog filter and digital filtering in the averaging engine produces an extremely sharp cutoff filter much steeper than would be possible with an ana log filter alone This offers the additional benefit of providing perfectly uniform group delay phase shift for all four channels Note also that the filter coefficients are automatically set to match the selected sampling rate without introducing any gain offset error The measurement data is then processed by the CPU and transmitted over the network to the h
24. follows of Manual Introduction This chapter provides an overview of DNx Al 224 Strain Gauge Analog Input Board features device architecture connectivity and logic This chapter also describes the the shunt calibration and auto null features of the DNx Al 224 layer Programming with the High Level API This chapter provides an overview of the how to create a session configure the session and interpret results with the Framework API Programming with the Low Level API This chapter is an overview of low level API commands for configuring and using the Al 224 series layer Appendix A Accessories This appendix provides a list of accessories available for use with the DNx AI 224 board Appendix B Shunt Calibration This appendix describes shunt calibration support in the Framework ndex This is an alphabetical listing of the topics covered in this manual quac R mw Ru uec mem m Hdo p m C R 2 or ew amp c cms Y c H B n Copyright 2013 f Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industies In Date September 2013 DNx AIl 224 Chap1x fm DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 Introduction Manual Conventions To help you get the most out of this manual and our products please note that we use the following conventions Tips ar
25. gh speed four channel strain gauge Interface input boards for UEI s data acquisition and control Cubes and RACKtangle I O Board racks respectively The boards provide an ideal combination of high speed accuracy and connection flexibility and are suitable for use in a wide variety of applications that include industrial military and testing applications The analog inputs offer 18 bit resolution at sample rates up to 100 000 samples per second 100kS s Each channel has an A D converter and all four channels are sampled simultaneously The combination of the 18 bit resolution with the board s automatic offset zeroing and automatic gain calibration ensure the measurements are extremely accurate Each channel also includes an anti aliasing filter that automatically is configured to match the sample rate The complex anti aliasing filter can reduce error by at least 72dB at rates of 100kHz The DNx Al 224 accepts inputs from full half or quarter bridge gauges and load cells Bridge completion resistors are built in for use with 1200 3500 and 10000 gauges also full bridge gauges of any resistance value may also be measured Each channel offers an independent excitation output user programmable from 0 to 10 Vac in 65535 steps 3mV The excitation outputs can drive up to 50 mA each allowing 1kQ bridges to be driven at 10 Vdc 350 ohm bridges at 8 75 V and 120 ohm bridges at up to 3 Vgc The board provides on board compression and tens
26. he Al 224 Layer ssssssssssee eene eene nennen nnns 8 1 4 The DNA AI 224 Analog Input Layer ssssssseeeeeenemeenn 9 1 5 Pinout Diagram of the Al 224 Layer eene 10 1 6 Full Bridge Strain Gauge Circuit ssseeennn enne 11 1 7 Half Bridge Strain Gauge Circuit ssseeeneeeenne enne 12 1 8 3 Wire Quarter Bridge Strain Gauge Circuit sses 13 1 9 Layout of DNA STP 62 Screw Terminal Panel essee en 14 1 10 Shunt Calibration cece ee ee iene eae ee eerie eene nenne nennen eren eere 15 A 1 Pinout and photo of DNA STP 62 screw terminal panel ccccceceeeeeeeeeeeeeeeees 21 B 1 Strain Gauge Bridge ssssssesssseseeee eene enne enn 22 B 2 Strain Gauge with Shunt Resistance Rs Added ssesssssee 23 Copyright 2013 Tel 508 921 4600 www ueidaq com Vers 4 6 Unita Elecironie Industries Ine Date September 2013 DNx Al 224 ManualLOF fm DNA DNR AI 224 High Speed Strain Gauge Input Board DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 Introduction Chapter 1 Introduction This document outlines the feature set and use of the DNR and DNA AI 224 layer The Al 224 is a four channel strain gauge input module for the PowerDNA I O Cube DNA AI 224 and the PowerDNR HalfRACK RACKtangle and the FIatRACK chassis DNR AI 224 1 4 Organization This Al 224 User Manual is organized as
27. ion shunt calibration with shunt calibration values selectable between 6 7kO and 170kQ within 1 1kQ Connections for external user supplied shunt resistors are also provided An automatic input nulling balancing capability has also been built in allowing most bridges to be quickly and easily balanced before testing actually begins As with all UEI PowerDNA boards the DNx Al 224 can be operated in harsh environments and has been tested at 5g vibration 50g shock 40 to 85 C temperature and altitudes up to 70 000 feet or 21000 meters Each board provides 350 V4 isolation between channels and also between the board and its enclosure or any other installed boards Software for the DNA DNR AI 224 is provided as part of the UEI Framework The framework provides a comprehensive yet easy to use API that supports all popular Windows programming languages as well as supporting programmers using Linux and most real time operating systems including QNX RTX RT Linux and more Finally the framework supplies complete support for those creating applications in LabVIEW MATLAB Simulink DASYLab or any application supporting ActiveX or OPC servers Copyright 2013 f Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industies In Date September 2013 DNx Al 224 Chap1x fm DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 Introduction 1 3 Features The Al 224 layer has the following features 4 strain gauge or load cell i
28. l PGA amplifier Half Bridge Mi Strain Gauge P o a 2 SHA External R R5K Shunt Cal DAC Itn P Rg1 Resistor SHA x PGA i S S a oe e v e S HER M Ri gt u L PGA A gt X P a Rg2 p2 External R Shunt Ca Bridge L Resistor es Completion sb s Resistors Al 224 Board Copyright 2013 United Electronic Industries Inc Figure 1 7 Half Bridge Strain Gauge Circuit As part of the internal shunt calibration function the Al 224 board measures the voltage drop across a precision 5K resistor and computes the exact value of the digital shunt with 02 accuracy This value is reported to the software The shunt may be adjusted from 6 7K to 170K ohms Note that the shunt may be switched to either side of the bridge tension or compression Tel 508 921 4600 www ueidaq com Vers 4 6 Date September 2013 DNx Al 224 Chap1x fm 1 8 3 Quarter Bridge Gauge Connections 3 wire Quarter Bridge Strain Gauge DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 13 Introduction Figure 1 8 shows the connections between a quarter bridge strain gauge and the Al 224 board Excitation voltage is applied between P and P and sensed between PS and PS As shown in the diagram below the board uses a pro grammable DAC to simulate the other half R5 R4 of the bridge The DAC out put is fed to the
29. nput channels 18 bit resolution up to 100 kS s Simultaneous sampling on all channels Built in aliasing filters both digital and analog 72dB min rejection Full half and quarter bridge 3 wire strain gauge inputs Input ranges of 10 0 078125 Vpc across full differential span where each differential input must be under 12V with respect to AGND Input impedance of 10 megaohm 120 350 and 1000 ohm bridge completion resistors provided on board for each channel Built in tension compression shunt calibration resistors selectable between 6 7k 170k within 1 1kO measured with 0 02 accuracy Connections provided for two external shunt resistors Independent 0 to 10 V DC or 20 V differential span 14V AC programmable excitation output on each channel 16 bit resolution Excitation outputs can drive up to 70 mA each allows 1k bridges to be driven across 20 V span 350 ohm at 17 5 Vdc and 120 ohm at 6 Vdc Automatic input nulling 16 bit resolution over a 10V range permits bridge balancing before starting tests Input ground to system ground isolation 350V ms Power consumption 3 5W max Weight of 136 g or 4 79 oz for DNA AI 224 817 g or 28 8 oz with PPC5 Tested to withstand 5g Vibration 50g Shock 40 to 85 C Temperature and Altitude up to 70 000 ft or 21000 meters UEI Framework Software API may be used with all popular Windows programming languages and most real time operating systems such as RT Linux R
30. ost in the normal manner Refer to Chapters 2 and 3 for pro gramming information 1 6 Auto Null To correct for any initial unbalance in the bridge the Al 224 may be automati Adjustment cally nulled by using the 224AutoNull function on any channel of the module This program automatically measures the zero unbalance and corrects the gain to eliminate the error 1 7 Indicators A photo of the DNx Al 224 unit is illustrated below The front panel has two LED indicators e RDY indicates that the layer is receiving power and operational e STS can be set by the user using the low level framework i DNA bus A connector RDY LED STS LED DB 62 female 62 pin I O connector Figure 1 4 The DNA AI 224 Analog Input Layer a xl ee e nc ea ae a mw i Se Se a mm n Copyright 2013 i Tel 508 921 4600 www ueidaq com Vers 4 6 AEG Eeeifanie y ngdaties UMS Date September 2013 DNx Al 224 Chap1x fm DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 10 Introduction 1 8 Layer Figure 1 5 below illustrates the pinout of the Al 224 Connectors and Wiring 21 1 QDSUUVUSPPPEEVAY E 4H 0 0000000000009 0 0 0 0 0 0 0 Hz 0 009000000000000090 62 43 Pin Signal Pin Signal Pin Signal o 1 QBIKCHO 22 GND CHO 43 P CHO g 2 PS CHO 23 PS CHO 44 P CHO 8 3 OBCHO S CHO 24 QB120 CHO 45 QB350 CHO O 4 S CHO 25 S CHO 46 SHA CH 0 P CH 0 5 SHB CH 0 P CH 0 26 SHA CH 0 S CH 0 47 NC 6 GNDCH1 27
31. ould not be allowed to exceed 12 5V or 12 5V relative to AGND Copyright 2013 United Electronic Industries Inc Tel 508 921 4600 Date September 2013 Vers 4 6 DNx Al 224 Chap1x fm www ueidaq com DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 Introduction 1 4 4 Characteristic The following graphs show the characteristic behavior of the Al 224 layer Graphs Figure 1 1 shows typical offset gain error that can be expected at various gain factors in percent e g 0 0003 offset error at a gain of 1 For the same set of measurements the noise in microvolts RMS that corresponds to gain is shown on the right Typical calibrated gain and offset errors 25 C 0 004 Gain 0 002 o Hm ee et r r 1 2 4 8 16 32 F F E 0 002 0 004 m Offset Error Gain Error 0 006 0 008 0 01 0 012 0 014 Typical RMS noise uV vs gain 25 C 1000 100 f Tb ki 2 4 8 16 32 64 128 256 Figure 1 1 Offset error and RMS noise vs gain Temperature changes the characteristics of the measured signal with this layer Input range uV drift uV C drift ppm C G 64 78125 0 5 2 G 64 312500 1 1 5 G 16 2500000 4 1 G 2 10000000 16 1 Table 1 2 Typical Temperature Drift for the Al 224 layer Copyright 2013 Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industries Inc Date September 2013 DN
32. puter In DMAP mode the delay between samples is determined by the Al 224 on board clock and data is transferred one scan at a time between PowerDNA and the host PC In buffered mode the delay between samples is determined by the Al 224 on board clock and data is transferred in blocks between PowerDNA and the host PC The following sample shows how to configure the simple mode Please refer to the UeiDaq Framework User s Manual to learn how to use other timing modes configure timing of input for point by point simple mode aiSession ConfigureTimingForSimpleIO Ee o zsC e Jg J j i Er OGCIBDIFI ET Copyright 2013 f Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industries Inc Date September 2013 DNx Al 224 Chap2x fm DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter2 19 Programming with the High Level API 2 5 Read Data Reading data is done using reader object s The following sample code shows how to create a scaled reader object and read samples create a reader and link it to the analog input session s stream CUeiAnalogScaledReader aiReader aiSession GetDataStream the buffer must be big enough to contain one value per channel double data 2 read one scan where the buffer will contain one value per channel aiReader ReadSingleScan data 2 6 Cleaning up The session object will clean itself up when it goes out of scope or when it is the Se
33. ssion destroyed To reuse the object with a different set of channels or parameters you can manually clean up the session as follows clean up the session aiSession CleanUp a a C c ee eee Copyright 2013 Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industries Inc Date September 2013 DNx Al 224 Chap2x fm Chapter 3 Function DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 3 Programming with the Low level API Programming with the Low level API The PowerDNA cube and PowerDNR RACKtangle and HalfRACK can be pro grammed using the low level API The low level API offers direct access to Pow erDNA DAQBios protocol and also allows you to access device registers directly However we recommend that when possible you use the UeiDaq Framework High Level API see Chapter 2 because it is easier to use You should need to use the low level API only if you are using an operating system other than Win dows For additional information about low level programming of the Al 224 please refer to the PowerDNA API Reference Manual document under Start Programs UEI PowerDNA Documentation Refer to the PowerDNA API Reference Manual on how to use the following low level functions of Al 224 as well as others related to cube operation Description DqAdv224Read Returns continously sampled data from input channel DqAdv224Se
34. t Get pointer to channel object CUeiAIVExChannel pChan dynamic cast CUeiAIVExChannel session GetChannel index 2 3 4 Bridge Use CreateAlVexChannel s bridgeType parameter to specify whether you are Completion using a full half or quarter bridge configuration If quarter or half bridge is specifed the bridge completion circuitry will be enabled automatically You can specify the bridge completion DAC level with Set bridge completion DAC level pChan SetBridgeCompletionSetting 0 0 Using a setting value of 0 0 will automatically calculate the proper setting value to complete the bridge make sure your strain gauge or load cell is not under Stress Start the session read a few data points and verify that they are close to 0 0 Stop the session and read the setting value that was calculated Get bridge completion DAC level auto calculated by setting to 0 0 bcSetting pChan gt GetBridgeCompletionSetting ce oad Copyright 2013 f Tel 508 921 4600 www ueidaq com Vers 4 6 United Electronic Industries Inc Date September 2013 DNx Al 224 Chap2x fm DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 2 18 Programming with the High Level API 2 3 2 AC Excitation CreateAlVexChannel configures the excitation as a DC signal by default You can change it to an AC signal by changing the channel frequency attribute Change the excitation frequency property default value is 0 0 for DC
35. tAveraging Sets the data averaging factor for any channel letion DgAdv224SetBridgeComp Sets the internal bridge completion voltage DgAdv224SetExcitation Sets the excitation voltage 20V 20V of a channel DgAdv224SetFIR Sets the FIR configuration for one or more channels DqAdv224SetNullLevel Sets the nulling voltage and will null at gains up to 40 Copyright 2013 United Electronic Industries Inc Tel 508 921 4600 www ueidaq com Vers 4 6 Date September 2013 DNx Al 224 Chap3 fm 20 DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 3 21 Programming with the Low level API 3 4 Decimation The default decimations and clock multiplication factors for the Al 224 are FIRO decimation 1 2 3 1 is Static uintl fir tbl decimo 8 25 2 NEC EP 23 L 95 95 FIR1 decimation 1 is Static uintl6 fir tbl decimi 81 0 al diy alk 1y T9 aly 3 decimation factors multiplied together static uintTo fir clock mult 8 a 6 LO 2A 48 96 192 384 The first element index 0 is for output data rates from gt 50 000 to 100 000 samples per second The remainder of the elements of the array are Index Data Rate S sec 0 gt 50000 lt 100000 gt 25000 lt 50000 gt 12500 lt 25000 gt 6250 lt 12500 gt 3125 lt 6250 gt 1562 5 lt 3125 gt 781 25 lt 1562 5 gt 390 625 lt 781 25 NIAJN BR Ww N
36. um rejection Input impedance Excitation Outputs Number of channels Output voltage 10 megohm min Two P P per channel independently programmable 0 to 10 Vdc each output 20Vdc diff span Resolution 16 bit Output drive current 50 mA max Output error Shunt Calibration Shunt range 5 mV max measured to the same accuracy as the analog input 6 7 kto 170k ohm tension or compression internal Also provides two connections for user supplied shunt resistors Shunt resolution 1 1k ohm Automatic Bridge Nulling Balancing Null balance range General Specifications Electrical isolation 350 Vrms chan chan and chan chassis Operating temperature Vibration IEC 60068 2 IEC 60068 2 64 6 19 bit resolution 10V auto null 1 mV max Tested 40 C to 85 C 5 g 10 500 Hz sinusoidal 5 g rms 10 500 Hz broad band random Shock Humidity Altitude IEC 60068 2 27 50 g 3 ms half sine 18 shocks 6 orientations 30g 11 ms half sine 18 shocks 6 orientations 0 to 95 non condensing 0 to 70 000 feet Power consumption 6 0 Watts 1 5 x excitation power supplied Range Vdc ESTO BED 25 X125 0 625 0 3125 0 15625 0 078125 Gain 4 8 16 32 64 128 256 For general purpose analog input note gain of 1x corresponds to a 20V range that is limited to 12 5V Input voltage on S amp S sh
37. x Al 224 Chap1x fm 6 DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 7 Introduction The figure below shows the noise amplitude observed at gain of 1 16 and 64 for the full range of the supported sampling frequencies The noise amplitude is the difference in amplitude of the actual measurement and the ideal result For example at gain 1 and sampling rate of 100kHz the difference between actual and ideal measurement is a typical 100dB of full scale or 0 00001V Typical Noise gain 1 10V Amplitude db of Full Scale a ee 110 0 5 310 15 20 25 30 35 40 45 50 55 G0 65 70 75 80 85 90 95 Sampling Frequency kHz Typical Noise gain 16 0 625V Amplitude db of Full Scale E co RD E UREUS 110 0 S5 310 15 20 25 30 35 40 45 530 55 60 65 70 75 80 85 90 95 Sampling Frequency kHz Typical Noise gain 64 0 15625V Amplitude db of Full Scale 90 E 73737870000865 75 100 0 5 310 1435 20 25 30 35 40 45 50 55 G0 65 70 75 80 85 90 95 Sampling Frequency kHz Figure 1 2 Noise amplitude at various sampling rates i a Copyright 2013 7 Tel 508 921 4600 www ueidaq com Vers 4 6 ea acca a Date September 2013 DNx Al 224 Chap1x fm DNA DNR AI 224 High Speed Strain Gauge Input Board Chapter 1 Introduction 1 5 Device Figure 1 3 is a block di
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