CALIBRATION PROCEDURE RM-4339 Rack-Mount Accessory Universal Bridge Français Deutsch ni.com/manuals This document contains the verification procedures for the National Instruments RM-4339. For more information about calibration solutions, visit ni.com/calibration. Contents Software.................................................................................................................................... 1 Documentation.......................................................................................................................... 2 Test Equipment......................................................................................................................... 3 Connecting the Calibrator to the RM-4339 ...................................................................... 4 Test Conditions......................................................................................................................... 4 Initial Setup............................................................................................................................... 5 Verification ............................................................................................................................... 5 SCA Shunt Calibration Resistance Accuracy Verification .............................................. 5 Offset Voltage Verification .............................................................................................. 7 Quarter-Bridge Shunt Calibration Accuracy Verification................................................ 9 Specifications............................................................................................................................ 12 World Wide Support and Services ........................................................................................... 13 Software Calibrating the NI RM-4339 requires the installation of NI-DAQmx on the calibration system. Driver support for the RM-4339 was first available in NI-DAQmx 14.5. For the list of devices supported by a specific release, refer to the NI-DAQmx Readme, available on the version-specific download page or installation media. You can download NI-DAQmx from ni.com/downloads. NI-DAQmx supports numerous programming languages, including LabVIEW, LabWindows™/CVI™, C/C++, C#, and Visual Basic .NET. When you install NI-DAQmx, you only need to install support for the application software that you intend to use. Documentation Consult the following documents for information about the RM-4339, NI-DAQmx, and your application software. All documents are available on ni.com and help files install with the software. NI PXIe-4339 and RM-4339 User Guide and Terminal Block Specifications NI-DAQmx installation, hardware setup, and RM-4339 specifications. NI PXIe-4339 and TB-4339/B/C Installation Guide and Terminal Block Specifications NI-DAQmx installation and hardware setup. NIPXIe-4339 User Manual NI PXIe-4339 specific information. NI PXIe-4339 Specifications NI PXIe-4339 specifications and calibration interval. NI-DAQmx Readme Operating system and application software support in NI-DAQmx. NI DAQmx Help Information about creating applications that use the NI-DAQmx driver. LabVIEW Help LabVIEW programming concepts and reference information about NI-DAQmx VIs and functions. NI-DAQmx C Reference Help Reference information for NI-DAQmx C functions and NI-DAQmx C properties. NI-DAQmx .NET Help Support for Visual Studio Reference information for NI-DAQmx .NET methods and NI-DAQmx .NET properties, key concepts, and a C enum to .NET enum mapping table. 2 | ni.com | RM-4339 Calibration Procedure Test Equipment Table 1 lists the equipment recommended for the performance verification procedures. If the recommended equipment is not available, select a substitute using the requirements listed in Table 1. Table 1. Recommended Equipment Equipment Recommended Model Requirements Calibrator Fluke 5520A If this instrument is unavailable, use a calibrator that can provide resistance values in the range of 120 Ω to 1 kΩ with 0.01 Ω resolution, and an accuracy of 90 ppm or better, and can sink 15 mA on the 120 Ω setting, 8 mA on the 350 Ω setting, and 3 mA on the 1 kΩ setting. Ohm Meter NI PXI-4070 If this instrument is unavailable, use a 6 ½ digit DMM with 2-wire resistance measurement capability and resistance accuracy of 80 ppm or better of reading +6 ppm of range for the 100 kΩ range. 8-Channel Universal-Bridge Input Module NI PXIe-4339 — Terminal Block Connection Accessory TB-4339/B/C — PXI Express Chassis NI PXIe-1062Q — Accessory Cable SH96-96-2 The SH96-96-2 is available in 1 meter, 3 meter and 5 meter lengths. Any of these cable lengths can be used. RJ50 to Pigtail Cable (8) NI P/N: 195950-02 An RJ50 cable with a cable wire resistance < 0.2 Ω with better than 10% resistance mismatch between individual wires. RM-4339 Calibration Procedure | © National Instruments | 3 Connecting the Calibrator to the RM-4339 Always have the NI PXI Express chassis powered off when inserting a module into the chassis. Caution Refer to the specific verification procedure section for information describing the required connections. To minimize the number of verification connection changes, the connections for SCA shunt calibration resistance verification and quarter-bridge shunt calibration verification can be made simultaneously. Note The RM-4339 provides support for up to three NI PXIe-4339 modules. The 96-pin DIN connectors used to connect the NI PXIe-4339 to the RM-4339 through the SH96-96-2 cable are located on the rear of the RM-4339 and are labeled A, B, and C. To fully verify the RM-4339, each of the verification procedures in this document must be conducted for each position A, B, and C. Refer to the NI PXIe-4339 and RM-4339 User Guide and Terminal Block Specifications for information about how to install and use the RM-4339. Test Conditions The following setup and environmental conditions are required to ensure the RM-4339 meets published specifications. • Keep connections to the RM-4339 as short as possible. Long cables and wires act as antennas, picking up extra noise that can affect measurements. • Verify that all connections are secure. • Shielded and twisted pair copper wire is recommended for all cable connections to help prevent external noise sources from coupling into the measurements. • Maintain an ambient temperature of 23 °C ± 5 °C. The offset voltage verification procedure requires less than 1 °C of ambient temperature variation over the duration of the test. Refer to Offset Voltage Verification procedure for more details. • Keep relative humidity below 80%. • Allow a warm-up time for each of the instruments used in this procedure according to the specific instruments operating instructions. • Ensure that the PXI Express chassis fan speed is set to HIGH, that the fan filters are clean, and that the empty slots contain filler panels. For more information, refer to the Maintain Forced-Air Cooling Note to Users document available at ni.com/manuals. 4 | ni.com | RM-4339 Calibration Procedure Initial Setup Refer to the NI PXIe-4339 and RM-4339 User Guide and Terminal Block Specifications for information about how to install the software and hardware, and how to configure the device in Measurement & Automation Explorer (MAX). Note When a device is configured with MAX, it is assigned a device identifier. Each function call uses this identifier to determine which DAQ device to verify, or verify and adjust. In this document, Dev1 was used for inputs that required a device identifier. Verification The following performance verification procedures describe the sequence of operation and provides test points required to verify the RM-4339. The verification procedures assume that adequate traceable uncertainties are available for the calibration references. SCA Shunt Calibration Resistance Accuracy Verification This section provides instructions for verifying the RM-4339 SCA shunt calibration resistance accuracy. Throughout the shunt calibration resistance accuracy verification, use Table 3 to determine if the RM-4339 is operating within its specified range. Complete the following steps to test the accuracy of the RM-4339 SCA shunt calibration resistances: 1. Plug an RJ50 cable into the RM-4339s RJ50 connector of the channel you want to verify. Connect SCA (pin 1) of the RJ50 cable to the DMM HI input and connect SCA (pin 10) of the RJ50 cable to the DMM LO input as shown in Figure 1. Figure 1. RJ50 to DMM Connections RJ50 Connector on the RM-4339 DMM HI SCA (pin1) Ω Input LO 2. SCA (pin 10) Configure the DMM for a 2-wire resistance measurement. RM-4339 Calibration Procedure | © National Instruments | 5 3. Create a task to enable SCA shunt calibration. a. Create and configure an AI Bridge (V/V) measurement according to the values found in Table 2. Table 2. AI Bridge Configuration Configuration Channel Name Value Dev1/aix, where x refers to the channel number. Measurement Type AI Bridge (V/V) Voltage Excitation Source Internal Voltage Excitation Value 3.3 Maximum Value 0.01 Minimum Value -0.01 Units V/V Bridge Configuration Full Sample Mode Finite Samples Sample Clock Rate 100 Samples per Channel 100 b. Enable the SCA shunt calibration circuit using the following parameters: Property Node: DAQmx Channel AI.Bridge.ShuntCal.Select: A AI.Bridge.ShuntCalASrc: Built-In AI.Bridge.ShuntCal.ShuntCalAResistance: 100 k AI.Bridge.ShuntCal.Enable: True Note These properties are located at Analog Input»General Properties»Signal Conditioning»Bridge»Shunt Cal. c. Commit the task by calling DAQmx Control Task with the following parameter: Action: Commit 4. Take a resistance measurement from the DMM and record the result. 5. Compare the result from step 4 to the Upper Limit and Lower Limit values in Table 3. If the result is between these values, the module passes the test. 6. Clear the task by calling DAQmx Clear Task. 6 | ni.com | RM-4339 Calibration Procedure 7. Repeat steps 1 through 6 for each channel you want to verify. 8. Disconnect the DMM from the module. Table 3. SCA Shunt Calibration Resistance Accuracy Limits Nominal Value (Ω) Lower Limit (Ω) Upper Limit (Ω) 100,000 99,900 100,100 Offset Voltage Verification The offset voltage verification uses the NI PXIe-4339 to measure the offset voltage of the RM-4339. Prior to measuring the offset voltage of the RM-4339, an offset characterization is performed on the NI PXIe-4339 using a TB-4339/B/C to provide an electrical short on the input of the NI PXIe-4339. The temperature variation of the environment should be kept within 1 °C between measurement of the offset error of the NI PXIe-4339 and the offset measurement of the RM-4339. Complete the following steps to verify the offset voltage: 1. Make the following connections: a. On the TB-4339/B/C, short the AI+ and AI- of all the channels to AIGND. Note Refer to the NI PXIe-4339 and TB-4339/B/C Installation Guide and Terminal Block Specifications for the pin assignments and signal names. b. Connect the female end of the SH96-96-2 cable to the NI PXIe-4339. c. Connect the TB-4339/B/C to the male end of the SH96-96-2 cable. RM-4339 Calibration Procedure | © National Instruments | 7 2. Acquire voltage measurements from all channels with the NI PXIe-4339. a. Create and configure an AI voltage measurement according to the values found in Table 4. Table 4. AI Voltage Mode Setup Configuration Channel Name Measurement Type Value Dev1/ai0:7 AI Voltage Maximum Value 0.01 Minimum Value -0.01 Units Volts Input Terminal Configuration Sample Mode Default Finite Samples Sample Clock Rate 100 Samples per Channel 100 b. Start the task by calling DAQmx Start Task. c. Average the readings that you acquired and record the vales as VoffsetPXIe-4339Chx, where x is the channel number. d. Clear the task by calling DAQmx Clear Task. 3. Remove the TB-4339/B/C from the SH96-96-2 cable and connect the SH96-96-2 cable to the 96-pin connector on the back of the RM-4339. 4. Connect an RJ50 cable to each channel with AI+ (pin 2) and AI- (pin 3) connected to T- (pin 9). 5. Acquire voltage measurements from all channels with the NI PXIe-4339. 8 | a. Create and configure an AI voltage measurement according to the values found in Table 4. b. Start the task by calling DAQmx Start Task. c. Average the readings that you acquired and subtract VoffsetPXIe-4339Chx from the average values for each channel. ni.com | RM-4339 Calibration Procedure d. Compare the values obtained in step c with those in Table 5. e. Clear the task by calling DAQmx Clear Task. Table 5. Offset Voltage Accuracy Limits Range (V) Minimum Maximum Test Point (V) Lower Limit (V) Upper Limit (V) -0.1 0.1 0 -0.000010 0.000010 Quarter-Bridge Shunt Calibration Accuracy Verification Complete the following procedure to verify the quarter-bridge shunt calibration accuracy of the RM-4339: 1. Set the calibrator to standby mode (STBY). 2. Using an RJ50 cable connect the calibrator to the channel of the RM-4339 you want to verify. Note a. Only one channel can be connected to the calibrator at a time. Connect EX+ (pin 6) to Ω HI, connect QTR (pin 5) to Ω LO and connect AI+ (pin 2) to Ω LO as shown in Figure 2. Figure 2. RJ50 to Calibrator Connections RJ50 Connector on the RM-4339 Calibrator HI Normal Ω Output AI+ (pin 2) LO b. EX+ (pin 6) QTR/RS(pin 5) QTR and AI+ must be connected together at the calibrator. The EX+ lead wire and the QTR lead wire must be the same length. 3. Set the calibrator output to 120 Ω, 350 Ω, or 1000 Ω depending on the quarter-bridge configuration you want to verify. This must match the configuration setting made in step 6 a. 4. Set the calibrator output for compensation off (COMP off). 5. Set the calibrator to operate mode (OPR) to enable the output. RM-4339 Calibration Procedure | © National Instruments | 9 6. Acquire an AI Bridge (V/V) measurement with shunt calibration disabled. a. Create and configure an AI Bridge (V/V) channel according to the values found in Table 6. Table 6. AI Bridge (V/V) Mode Setup Configuration Channel Name Value Dev1/aix, where x refers to the channel number Measurement Type AI Bridge (V/V) Bridge Configuration Quarter Nominal Bridge Resistance 120 Ω, 350 Ω, 1000 Ω Voltage Excitation Source Internal Voltage Excitation Value 3.3 V for 120 Ω configuration, 5 V for 350 Ω and 1 kΩ configurations Maximum Value 0.01 Minimum Value -0.01 Units V/V Sample Mode Finite Samples Sample Clock Rate 100 Samples per Channel 100 * Use the bridge resistance value that corresponds to the configuration being verified. b. Disable the SCB shunt calibration circuit using the following parameters: Property Node: DAQmx Channel AI.Bridge.ShuntCal.Enable: False c. Commit the task by calling DAQmx Control Task with the following parameter: Action: Commit 7. 10 d. Wait 5 seconds to allow the circuitry to stabilize. If the calibrator requires more than a 5 second wait time, use the wait time required by the calibrator. e. Start the task by calling DAQmx Start Task. f. Average the readings that you acquired and record the values as ResultSCD. g. Clear the task by calling DAQmx Clear Task. Acquire an AI Bridge (V/V) measurement with shunt calibration enabled. a. Create a task. b. Create and configure an AI Bridge (V/V) channel according to the values found in Table 6. | ni.com | RM-4339 Calibration Procedure c. Enable the SCB shunt calibration circuit using the following parameters: Property Node: DAQmx Channel AI.Bridge.ShuntCal.Select: B AI.Bridge.ShuntCal.ShuntCalBResistance: 50k for 120 Ω, 100k for 350 Ω and 1 kΩ AI.Bridge.ShuntCal.Enable: True 8. d. Start the task by calling DAQmx Start Task. e. Average the readings that you acquired and record the values as ResultSCE. f. Clear the task by calling DAQmx Clear Task. Calculate the shunt calibration scaling factor as follows: SCalScaleFactor = SCalExp/(ResultSCE - ResultSCD) where SCalExp is the expected shunt calibration deflection, given in the following, for each of the supported quarter-bridge completion values. SCalExp = -0.00059928 for 120 Ω SCalExp = -0.00087347 for 350 Ω SCalExp = -0.00248756 for 1 kΩ For reference, the calculation for the expected shunt calibration deflection is given by the following equation: R eq SCalExp = ------------------------- – 0.5 R eq + R qtr where Req is the equivalent parallel resistance of the quarter-bridge and shunt calibration resistors. Rqtr is the resistance of the quarter-bridge completion resistor. 9. Set the calibrator output to the value of the Calibrator Output indicated in Table 7 for the quarter-bridge configuration that is being verified. 10. Acquire an AI Bridge (V/V) measurement. a. Create a task. b. Create and configure an AI Bridge (V/V) channel according to the values found in Table 6. c. Disable the SCB shunt calibration circuit using the following parameters: Property Node: DAQmx Channel AI.Bridge.ShuntCal.Enable: False d. Start the task by calling DAQmx Start Task. e. Average the readings that you acquired, subtract ResultSCD from the averaged result, and record the values as UnscaledOffsetComp. RM-4339 Calibration Procedure | © National Instruments | 11 f. Multiply UnscaledOffsetComp by SCalScaleFactor that was calculated in step 8 and record the value as ScaledOffsetComp. g. Compare ScaledOffsetComp to the Upper and Lower Limits from Table 7 for the quarter-bridge configuration that is being verified. If the results are within the Upper and Lower Limits the device passes the verification test. h. Clear the task by calling DAQmx Clear Task. 11. Repeat steps 3 through 10 for each quarter-bridge configuration. 12. Repeat steps 1 through 11 for each channel. 13. Set the calibrator to standby mode (STBY). 14. Disconnect the calibrator from the device. Table 7. Quarter-Bridge Shunt Calibration Accuracy Limits Quarter-Bridge Completion (Ω Calibrator Output (Ω) Nominal Value (V/V) Lower Limit (V/V) Upper Limit (V/V) 120 116.0 0.0084746 0.0084449 0.0085042 350 338.4 0.0084253 0.0084043 0.0084464 1000 966.8 0.0084401 0.0084190 0.0084612 Test limits in this document are based upon the March 2015 edition of the NI PXIe-4339 and RM-4339 User Guide and Terminal Block Specifications. Refer to the most recent NI PXIe-4339 and RM-4339 User Guide and Terminal Block Specifications online at ni.com/manuals. Note If the device is not operating within the specified values, refer to the World Wide Support and Services section for assistance in returning the device to NI. Specifications Refer to the NI PXIe-4339 and RM-4339 User Guide and Terminal Block Specifications for detailed specification information. 12 | ni.com | RM-4339 Calibration Procedure World Wide Support and Services The National Instruments website is your complete resource for technical support. At ni.com/ support you have access to everything from troubleshooting and application development self-help resources to email and phone assistance from NI Application Engineers. Visit ni.com/services for NI Factory Installation Services, repairs, extended warranty, and other services. Visit ni.com/register to register your National Instruments product. Product registration facilitates technical support and ensures that you receive important information updates from NI. National Instruments corporate headquarters is located at 11500 North Mopac Expressway, Austin, Texas, 78759-3504. National Instruments also has offices located around the world. For telephone support in the United States, create your service request at ni.com/support or dial 1 866 ASK MYNI (275 6964). For telephone support outside the United States, visit the Worldwide Offices section of ni.com/niglobal to access the branch office websites, which provide up-to-date contact information, support phone numbers, email addresses, and current events. Refer to the NI Trademarks and Logo Guidelines at ni.com/trademarks for more information on National Instruments trademarks. Other product and company names mentioned herein are trademarks or trade names of their respective companies. For patents covering National Instruments products/technology, refer to the appropriate location: Help»Patents in your software, the patents.txt file on your media, or the National Instruments Patents Notice at ni.com/patents. You can find information about end-user license agreements (EULAs) and third-party legal notices in the readme file for your NI product. Refer to the Export Compliance Information at ni.com/legal/export-compliance for the National Instruments global trade compliance policy and how to obtain relevant HTS codes, ECCNs, and other import/export data. NI MAKES NO EXPRESS OR IMPLIED WARRANTIES AS TO THE ACCURACY OF THE INFORMATION CONTAINED HEREIN AND SHALL NOT BE LIABLE FOR ANY ERRORS. U.S. Government Customers: The data contained in this manual was developed at private expense and is subject to the applicable limited rights and restricted data rights as set forth in FAR 52.227-14, DFAR 252.227-7014, and DFAR 252.227-7015. © 2015 National Instruments. All rights reserved. 374920A-01 Mar15