SCXI-1120 National Instruments Voltage Input Module | Apex Waves
User Guide for NATIONAL INSTRUMENTS models including: SCXI-1120 Voltage Input Amplifier Module, SCXI-1120, Voltage Input Amplifier Module, Input Amplifier Module, Amplifier Module, Module
SCXI-1120 National Instruments Voltage Input Module | Apex Waves
File Info : application/pdf, 20 Pages, 1.58MB
DocumentDocumentSCXI-1120 CALIBRATION PROCEDURE SCXITM-1120/D Introduction This document contains information and step-by-step instructions for calibrating the National Instruments (NI) SCXI-1120 and SCXI-1120D modules. What Is Calibration? Calibration consists of verifying the measurement accuracy of a module and adjusting for any measurement error. Verification is measuring the performance of the module and comparing these measurements to the factory specifications. During calibration, you supply and read voltage levels using external standards, then you adjust the module calibration circuitry. This circuitry compensates for any inaccuracies in the module, and returns the accuracy of the module to the factory specifications. Why Should You Calibrate? The accuracy of electronic components drifts with time and temperature, which can affect measurement accuracy as a module ages. Calibration restores these components to their specified accuracy and ensures that the module still meets NI standards. How Often Should You Calibrate? The measurement requirements of your application determine how often the SCXI-1120/D module needs to be calibrated to maintain accuracy. NI recommends that you perform a complete calibration at least once every year. You can shorten this interval to 90 days or six months based on the demands of your application. National InstrumentsTM, NITM, ni.comTM, and SCXI TM are trademarks of National Instruments Corporation. Product and company names mentioned herein are trademarks or trade names of their respective companies. 370268B-01 © 2000, 2001 National Instruments Corp. All rights reserved. September 2001 Equipment and Other Test Requirements This section describes the test equipment, software, documentation, and test conditions required for calibrating the SCXI-1120/D modules. Test Equipment Calibration requires a high-precision voltage source with at least 50 ppm accuracy and a multiranging 5 1/2 digit digital multimeter (DMM) with 15 ppm accuracy. Instruments NI recommends the following instruments for calibrating SCXI-1120/D modules: · Calibrator--Fluke 5700A · DMM--NI 4060 or HP 34401A If these instruments are not available, use the accuracy requirements listed previously to select substitute calibration instruments. Connectors If you do not have custom connection hardware, you need the following connectors: · Terminal block, such as the SCXI-1320 · Shielded 68-pin connector cable · 50-pin ribbon cable · 50-pin breakout box · SCXI-1349 adapter These components give easy access to the individual pins on the SCXI-1120/D module front and rear connectors. Software and Documentation No special software or documentation is necessary to calibrate the SCXI-1120/D module. This calibration document contains all the information you need to complete the verification and adjustment procedures. If you would like more information on the module, refer to the SCXI-1120/D User Manual. SCXI-1120/D Calibration Procedure 2 ni.com Test Conditions Calibration Follow these guidelines to optimize the connections and environment during calibration: · Keep connections to the SCXI-1120/D module short. Long cables and wires act as antennae, picking up extra noise and thermal offsets that can affect measurements. · Use shielded copper wire for all cable connections to the device. Use twisted-pair wire to eliminate noise and thermal offsets. · Maintain the temperature between 1828 °C. · Keep relative humidity below 80%. · Allow a warm-up time of at least 15 minutes for the SCXI-1120/D module to ensure the measurement circuitry is at a stable operating temperature. The calibration procedure for the SCXI-1120/D module consists of the following steps: 1. Set up the module for testing. 2. Verify the existing operation of the module to determine whether it is operating within its specifications. 3. Adjust the module with respect to a known voltage source. 4. Verify that the module is operating within its specifications after adjustments. © National Instruments Corporation 3 SCXI-1120/D Calibration Procedure Setting Up the Module Refer to Figures 1 and 2 while performing the following steps to set up the SCXI-1120/D module for verification: 1. Remove the grounding screw from the module. 2. Remove the cover on the module to access the potentiometers. 2 1 1 Grounding screw 2 Module cover Figure 1. Grounding Screw and Module Cover Removal 3. Remove the side plate of the SCXI chassis. 4. Install the SCXI-1120/D into slot 4 of the SCXI chassis. SCXI-1120/D Calibration Procedure 4 ni.com ® SCXI MAINFRAME INNSATTRIOUNMAELNTS 2 3 1 Thumbscrews 1 2 Slot 4 3 Side plate Figure 2. Side Plate Removal and Module Installation The SCXI-1120/D module does not need to be connected to a data acquisition (DAQ) device. Leave the configuration of the digital jumpers W41W43 and W46 unchanged because they do not affect this procedure. Configuring the Gain Jumpers Each input channel has two user-configurable gain stages. The first-stage gain provides gains of 1, 10, 50, and 100. The second-stage gain provides gains of 1, 2, 5, 10, and 20. Table 1 shows the jumper reference designators for gain selection associated with each channel. Table 2 shows how to position each jumper to select the desired gain for each channel. Table 1. Gain Jumper Reference Designators Input Channel Number 0 First-Stage Gain Jumper W1 Second-Stage Gain Jumper W9 1 W2 W10 2 W3 W11 © National Instruments Corporation 5 SCXI-1120/D Calibration Procedure Table 1. Gain Jumper Reference Designators (Continued) Input Channel Number First-Stage Gain Jumper Second-Stage Gain Jumper 3 W4 W12 4 W5 W13 5 W6 W14 6 W7 W15 7 W8 W16 Gain First Stage Second Stage Table 2. Gain Jumper Positions Setting Jumper Position 1 D 10 C 50 B 100 A (factory setting) 1 A 2 B 5 C 10 D (factory setting) 20 E To change the gain setting of a specified channel on the module, move the appropriate jumper on the module to the position indicated in Table 2. Refer to Table 1 for jumper reference designators, and Figure 3 for the location of the jumpers. SCXI-1120/D Calibration Procedure 6 ni.com 3 1 4 5 V25 V26 W27 W28 W29W30 W31V32V33 W34 W35 W36 V37 V38 V39 V40 6 2 W43 7 W45 W42 1 12 22 W14 U14 AD705 GAINDIP AD Q12 R18 W6 ABCDABCDEAB 8 9 10 11 12 Front 13 Rear 1 Thumbscrews 2 Front Connector 3 Product Name, Assembly Number, and Serial Number 4 Output Null Adjust Potentiometers 5 Second-Stage Filter Jumpers 6 Rear Signal Connector 7 SCXIbus Connector 8 Input Null Adjust Potentiometers 9 First-Stage Gain Jumpers 10 Second-Stage Gain Jumpers 11 First-Stage Filter Jumpers 12 Terminal Block Mounting Hole 13 Grounding Screw Figure 3. SCXI-1120/D Parts Locator Diagram Note The SCXI-1120D module has an additional fixed pre-stage gain of 0.5. © National Instruments Corporation 7 SCXI-1120/D Calibration Procedure The order of the settings for the first- and second-stage gain does not matter as long as the first-stage gain multiplied by the second-stage gain--multiplied by 0.5 when using the SCXI-1120D--equals the desired final gain value. · SCXI-1120--To determine the overall gain of a given channel on the SCXI-1120 module: First-Stage Gain × Second-Stage Gain = Overall Gain · SCXI-1120D--To determine the overall gain of a given channel on the SCXI-1120D module: (First-Stage Gain × Second-Stage Gain) × 0.5 = Overall Gain Configuring the Filter Jumpers Each input channel also has two user-configurable filter stages. The SCXI-1120 module ships in the 4 Hz position and the SCXI-1120/D module ships in the 4.5 kHz position. Refer to Table 3 or 4 to find the correct jumper setting for the desired cutoff frequency. Figure 3 shows the locations of the jumper blocks on the SCXI-1120/D modules. Verify that both filter stages are set to the same filter setting to ensure that you achieve the required bandwidth. Table 3. SCXI-1120 Filter Jumper Settings Input Channel Number First Filter Jumper 4 Hz (Factory Setting) 10 kHz Second Filter Jumper 4 Hz (Factory Setting) 10 kHz 0 W17-A W17-B W25 W26 1 W18-A W18-B W27 W28 2 W19-A W19-B W29 W30 3 W20-A W20-B W31 W32 4 W21-A W21-B W33 W34 5 W22-A W22-B W35 W36 6 W23-A W23-B W37 W38 7 W24-A W24-B W39 W40 SCXI-1120/D Calibration Procedure 8 ni.com Input Channel Number 0 1 2 3 4 5 6 7 Table 4. SCXI-1120D Filter Jumper Allocation First Filter Jumper Second Filter Jumper 4.5 kHz (Factory Setting) 22.5 kHz 4.5 kHz (Factory Setting) 22.5 kHz W17-A W17-B W26 W25 W18-A W18-B W28 W27 W19-A W19-B W30 W29 W20-A W20-B W32 W31 W21-A W21-B W34 W33 W22-A W22-B W36 W35 W23-A W23-B W38 W37 W24-A W24-B W40 W39 Verifying the Operation of the Module The verification procedure determines how well the SCXI-1120/D module is meeting its specifications. You can use this information to select the appropriate calibration interval for your application. Refer to the Setting Up the Module section for information on how to configure the channel filter and channel gain. Complete the following steps to verify the operation of the SCXI-1120/D module: 1. Read the Test Conditions section in this document. 2. Refer to Table 7 for the SCXI-1120 module or Table 8 for the SCXI-1120D module for all acceptable settings for the module. Although NI recommends verifying all ranges and gains, you can save time by checking only those ranges used in your application. 3. Set the channel filter for all channels on the module to 4 Hz for the SCXI-1120 module or 4.5 kHz for the SCXI-1120D module. 4. Set the channel gain on all channels to the gain you want to test, starting with the smallest gain available for the module. Available gains are shown in Tables 7 and 8. 5. Connect the calibrator to the analog input channel you are testing, starting with channel 0. If you do not have an SCXI terminal block such as the SCXI-1320, refer to Table 5 to determine the pins on the 96-pin front connector that correspond to the positive and negative inputs of the specified channel. © National Instruments Corporation 9 SCXI-1120/D Calibration Procedure For example, the positive input for channel 0 is pin A32, which is labeled CH0+. The negative input for channel 0 is pin C32, which is labeled CH0. Table 5. SCXI-1120/D Front Connector Pin Assignments Pin Number 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 Column A CH0+ NP CH1+ NP NC NP CH2+ NP CH3+ NP NC NP CH4+ NP CH5+ NP NC NP CH6+ NP CH7+ NP NC NP NC Column B NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP Column C CH0 NP CH1 NP NC NP CH2 NP CH3 NP NC NP CH4 NP CH5 NP NC NP CH6 NP CH7 NP NC NP RSVD SCXI-1120/D Calibration Procedure 10 ni.com Table 5. SCXI-1120/D Front Connector Pin Assignments (Continued) Pin Number Column A 7 NP 6 RSVD 5 NP 4 +5V 3 NP 2 CHSGND 1 NP NP--No pin; NC--No connect Column B NP NP NP NP NP NP NP Column C NP RSVD NP MTEMP NP DTEMP NP 6. Connect the DMM to the output of the same channel to which the calibrator was connected in step 5. Refer to Figure 4 to determine the pins on the 50-pin rear connector that correspond to the positive and negative outputs for the specified channel. For example, the positive output for channel 0 is pin 3, which is labeled MCH0+. The negative output for channel 0 is pin 4, which is labeled MCH0. © National Instruments Corporation 11 SCXI-1120/D Calibration Procedure AOGND MCH0+ MCH1+ MCH2+ MCH3+ MCH4+ MCH5+ MCH6+ MCH7+ OUTREF NC NC SERDATIN DAQD*/A SLOT0SEL* NC DIG GND NC SERCLK NC NC RSVD NC NC NC 12 34 56 78 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 AOGND MCH0 MCH1 MCH2 MCH3 MCH4 MCH5 MCH6 MCH7 NC NC DIG GND SERDATOUT NC NC NC NC SCANCLK NC NC NC NC NC NC NC Figure 4. SCXI-1120/D Rear Connector Pin Assignments 7. Set the calibrator voltage to the value specified by the Test Point entry listed in Table 7 for the SCXI-1120 module or Table 8 for the SCXI-1120D module. 8. Read the resulting output voltage on the DMM. If the output voltage result falls between the Upper Limit and the Lower Limit values, the module passed the test. 9. Repeat steps 5 through 8 for the remaining test points. 10. Repeat steps 5 through 9 for the remaining analog input channels. 11. Repeat steps 4 through 10 for the remaining gain settings specified in the appropriate table. 12. Repeat steps 3 through 11, but set the channel filter to 10 kHz for the SCXI-1120 module or 22.5 kHz for the SCXI-1120D module. You have completed verifying the operation of the module. SCXI-1120/D Calibration Procedure 12 ni.com Adjusting Offset Null Values of the Module Complete the following steps to adjust the offset null value: 1. Set the channel gain on all channels to a gain of 1. Set the filter value to 4 Hz for the SCXI-1120 module or 4.5 kHz for the SCXI-1120D module. Refer to the Setting Up the Module section in this document for information on how to set the channel gain. 2. Connect the calibrator to the analog input channel you want to adjust, starting with channel 0. Refer to Table 5 to determine the pins on the 96-pin front connector that correspond to the positive and negative inputs of the specified channel. For example, the positive input for channel 0 is pin A32, which is labeled CH0+. The negative input for channel 0 is pin C32, which is labeled CH0. 3. Connect the DMM to the output of the same channel to which the calibrator was connected in step 2. Refer to Figure 4 to determine the pins on the 50-pin rear connector that correspond to the positive and negative outputs for the specified channel. For example, the positive output for channel 0 is pin 3, which is labeled MCH0+. The negative output for channel 0 is pin 4, which is labeled MCH0. 4. Set the calibrator to output 0.0 V. 5. Adjust the output potentiometer of the channel until the DMM reading is 0 ±3.0 mV. Refer to Figure 3 for the potentiometer location and Table 6 for the potentiometer reference designator. Table 6. Calibration Potentiometers Reference Designators Input Channel Number Input Null Output Null 0 R08 R24 1 R10 R25 2 R12 R26 3 R14 R27 4 R16 R28 5 R18 R29 6 R20 R30 7 R21 R31 6. Set the channel gain on all channels to 1000.0. © National Instruments Corporation 13 SCXI-1120/D Calibration Procedure 7. Adjust the input potentiometer of channel 0 until the DMM reading is 0 ±6.0 mV. Refer to Figure 3 for the potentiometer location and Table 6 for the potentiometer reference designator. 8. Repeat steps 1 through 7 for the remaining analog inputs. You have completed adjusting the module. Verifying Adjusted Values After you complete the adjustment procedure, it is important to verify the accuracy of the adjusted values by repeating the procedure in the Verifying the Operation of the Module section. Verifying the adjusted values ensures the module is operating within its specifications after adjustments. Note If the SCXI-1120/D module fails after calibration, return it to NI for repair or replacement. SCXI-1120/D Calibration Procedure 14 ni.com Specifications Gain 0.011 0.011 0.011 0.021 0.021 0.021 0.051 0.051 0.051 0.11 0.11 0.11 0.21 0.21 0.21 0.51 0.51 0.51 1 1 1 Table 7 contains test specifications for SCXI-1120 modules. Table 8 contains test specifications for SCXI-1120D modules. If the module was calibrated within the last year, the output from the module should fall between the Upper Limit and Lower Limit values. Table 7. SCXI-1120 Specifications Test Point (V) 232.5 0 4Hz filter setting Upper Limit Lower Limit (V) (V) 2.346996 2.303004 0.006888 0.006888 10kHz filter setting Upper Limit Lower Limit (V) (V) 2.349248 2.300752 0.009140 0.009140 232.5 186 0 186 93 0 93 46.5 0 2.346996 3.751095 0.006922 3.751095 4.687000 0.006784 4.687000 4.686925 0.006709 2.303004 3.688905 0.006922 3.688905 4.613000 0.006784 4.613000 4.613075 0.006709 2.349248 3.753353 0.009180 3.753353 4.689236 0.009020 4.689236 4.689186 0.008970 2.300752 3.686647 0.009180 3.686647 4.610764 0.009020 4.610764 4.610814 0.008970 46.5 23.25 0 23.25 4.686925 4.686775 0.006559 4.686775 4.613075 4.613225 0.006559 4.613225 4.689186 4.689056 0.008840 4.689056 .610814 4.610944 0.008840 4.610944 9.3 4.686353 4.613647 4.688626 4.611374 0 0.006138 0.006138 0.008410 0.008410 9.3 4.686353 4.613647 4.688626 4.611374 4.65 4.691704 4.608296 4.693926 4.606074 0 0.011488 0.011488 0.013710 0.013710 4.65 4.691704 4.608296 4.693926 4.606074 © National Instruments Corporation 15 SCXI-1120/D Calibration Procedure Gain 2 2 2 5 5 5 10 10 10 20 20 20 50 50 50 100 100 100 200 200 200 250 250 250 500 500 Table 7. SCXI-1120 Specifications (Continued) 4Hz filter setting 10kHz filter setting Test Point (V) Upper Limit Lower Limit Upper Limit Lower Limit (V) (V) (V) (V) 2.325 4.690653 4.609347 4.692876 4.607124 0 0.010437 0.010437 0.012660 0.012660 2.325 4.690653 4.609347 4.692876 4.607124 0.93 4.690498 4.609502 4.692726 4.607274 0 0.010282 0.010282 0.012510 0.012510 0.93 4.690498 4.609502 4.692726 4.607274 0.465 4.690401 4.609599 4.692626 4.607374 0 0.010185 0.010185 0.012410 0.012410 0.465 4.690401 4.609599 4.692626 4.607374 0.2325 4.690139 4.609861 4.692416 4.607584 0 0.009924 0.009924 0.012200 0.012200 0.2325 4.690139 4.609861 4.692416 4.607584 0.093 4.690046 4.609954 4.692331 4.607669 0 0.009831 0.009831 0.012115 0.012115 0.093 4.690046 4.609954 4.692331 4.607669 0.0465 4.689758 4.610242 4.692066 4.607934 0 0.009542 -0.009542 0.011850 0.011850 0.0465 4.689758 4.610242 4.692066 4.607934 0.02325 4.689464 4.610536 4.691936 4.608064 0 0.009248 0.009248 0.011720 0.011720 0.02325 4.689464 4.610536 4.691936 4.608064 0.0186 4.689313 4.610687 4.692016 4.607984 0 0.009097 0.009097 0.011800 0.011800 0.0186 4.689313 4.610687 4.692016 4.607984 0.0093 4.689443 4.610557 4.692731 4.607269 0 0.009227 0.009227 0.012515 0.012515 SCXI-1120/D Calibration Procedure 16 ni.com Table 7. SCXI-1120 Specifications (Continued) 4Hz filter setting 10kHz filter setting Gain Test Point (V) Upper Limit Lower Limit Upper Limit Lower Limit (V) (V) (V) (V) 500 0.0093 4.689443 4.610557 4.692731 4.607269 1000 0.00465 4.693476 4.606524 4.698796 4.601204 1000 0 0.013260 0.013260 0.018580 0.018580 1000 0.00465 4.693476 4.606524 4.698796 4.601204 2000 0.002325 4.703044 4.596956 4.712556 4.587444 2000 0 0.022828 0.022828 0.032340 0.032340 2000 0.002325 4.703044 4.596956 1Value available only when used with the SCXI-1327 high-voltage terminal block 4.712556 4.587444 Gain 0.011 0.011 0.011 0.0251 0.0251 0.0251 0.051 0.051 0.051 0.11 0.11 0.11 0.251 Test Point (V) 232.5 0 232.5 186 0 186 93 0 93 46.5 0 46.5 18.6 Table 8. SCXI-1120D Specifications 4.5KHz filter setting 22.5KHz filter setting Upper Limit Lower Limit Upper Limit Lower Limit (V) (V) (V) (V) 2.351764 2.298236 2.365234 2.284766 0.006230 0.006230 0.019700 0.019700 2.351764 2.298236 2.365234 2.284766 4.698751 4.601249 4.733819 4.566181 0.007683 0.007683 0.042750 0.042750 4.698751 4.601249 4.733819 4.566181 4.697789 4.602211 4.768769 4.531231 0.006720 0.006720 0.077700 0.077700 4.697789 4.602211 4.768769 4.531231 4.698899 4.601101 4.841289 4.458711 0.007830 0.007830 0.150220 0.150220 4.698899 4.601101 4.841289 4.458711 4.701669 4.598331 5.028819 4.271181 © National Instruments Corporation 17 SCXI-1120/D Calibration Procedure Gain 0.251 0.251 0.5 0.5 0.5 1 1 1 2.5 2.5 2.5 5 5 5 10 10 10 25 25 25 50 50 50 100 100 100 Table 8. SCXI-1120D Specifications (Continued) 4.5KHz filter setting 22.5KHz filter setting Test Point Upper Limit Lower Limit Upper Limit Lower Limit (V) (V) (V) (V) (V) 0 0.010600 0.010600 0.337750 0.337750 18.6 4.701669 4.598331 5.028819 4.271181 9.3 4.697331 4.602669 4.703726 4.596274 0 0.006355 0.006355 0.012750 0.012750 9.3 4.697331 4.602669 4.703726 4.596274 4.65 4.697416 4.602584 4.710876 4.589124 0 0.006440 -0.006440 0.019900 0.019900 4.65 4.697416 4.602584 4.710876 4.589124 1.86 4.697883 4.602117 4.732426 4.567574 0 0.006908 0.006908 0.041450 0.041450 1.86 4.697883 4.602117 4.732426 4.567574 0.93 4.698726 4.601274 4.768726 4.531274 0 0.007750 0.007750 0.077750 0.077750 0.93 4.698726 4.601274 4.768726 4.531274 0.465 4.700796 4.599204 4.841236 4.458764 0 0.009820 0.009820 0.150260 0.150260 0.465 4.700796 4.599204 4.841236 4.458764 0.18 5.070004 3.929996 4.870004 4.129996 0 0.530350 0.530350 0.330350 0.330350 0.18 5.070004 3.929996 4.870004 4.129996 0.086 4.360392 4.239608 4.825892 3.774108 0 0.022500 0.022500 0.488000 0.488000 0.086 4.360392 4.239608 4.825892 3.774108 0.038 3.879624 3.720376 4.810624 2.789376 0 0.039800 0.039800 0.970800 0.970800 0.038 3.879624 3.720376 4.810624 2.789376 SCXI-1120/D Calibration Procedure 18 ni.com Table 8. SCXI-1120D Specifications (Continued) 4.5KHz filter setting 22.5KHz filter setting Gain Test Point Upper Limit Lower Limit Upper Limit Lower Limit (V) (V) (V) (V) (V) 250 0.0125 3.277438 2.972563 4.830188 1.419813 250 0 0.091500 0.091500 0.056751 1.644250 250 0.0125 3.277438 2.972563 4.830188 1.419813 500 0.006 3.273770 2.726230 4.810770 1.189230 500 0 0.176000 0.176000 1.713000 1.713000 500 0.006 3.273770 2.726230 4.810770 1.189230 1000 0.0029 3.416058 2.383942 4.895058 0.904942 1000 0 0.342000 0.342000 1.821000 1.821000 1000 0.0029 3.416058 2.383942 1Value available only when used with the SCXI-1327 high-voltage terminal block 4.895058 0.904942 © National Instruments Corporation 19 SCXI-1120/D Calibration Procedure