National Instruments SCXI-1121 Manual

CALIBRATION PROCEDURE
SCXI -1121
This document contains information and instructions for calibrating the
National Instruments SCXI-1121 signal conditioning module.
Contents
Introduction............................................................................................. 2
What Is Calibration? ........................................................................ 2
Why Should You Calibrate? ............................................................ 2
How Often Should You Calibrate? .................................................. 2
Software and Documentation.................................................................. 2
Test Equipment ....................................................................................... 3
Test Conditions ....................................................................................... 3
Calibration Process ................................................................................. 4
Initial Setup...................................................................................... 4
Configuring the Half-Bridge Completion Jumpers .................. 5
Configuring the Gain Jumpers.................................................. 7
Configuring the Filter Jumpers................................................. 8
Configuring the Excitation Jumpers ......................................... 9
Verification Procedure..................................................................... 10
Verifying Analog Input Offsets ................................................ 10
Verifying Voltage Excitation Limits ........................................ 11
Verifying Current Excitation Limits......................................... 12
Adjustment Procedure...................................................................... 13
Adjusting Analog Input Offsets................................................ 13
Adjusting Voltage Excitation ................................................... 14
Adjusting Current Excitation.................................................... 15
Verifying Adjusted Values .............................................................. 15
Test Limits .............................................................................................. 16
SCXI-1121 Front and Rear Panel Diagrams........................................... 19
™

SCXI-1121 Calibration Procedure 2 ni.com
Introduction
What Is Calibration?
Calibration consists of verifying the measurement accuracy of a device
and adjusting for any measurement error. Verification is measuring the
performance of the device and comparing these measurements to the
factory specifications. During calibration, you supply and read voltage
levels using external standards, then you adjust the device calibration
constants. The measurement circuitry compensates for any inaccuracies
in the device, and returns the accuracy of the device to the factory
specifications.
Why Should You Calibrate?
The accuracy of electronic components drifts with time and temperature,
which can affect measurement accuracy. Calibration restores these
components to their specified accuracy and ensures that the device still
meets NI standards.
How Often Should You Calibrate?
Calibrate the SCXI-1121 at a regular interval as defined by the
measurement accuracy requirements of your application. NI recommends
that you perform a complete calibration at least once every year. You
can shorten this interval based on the accuracy requirements of your
application.
Software and Documentation
You do not need any special software or documentation to calibrate the
SCXI-1121. This calibration document contains all the information you
need to complete the calibration procedure. Refer to the SCXI-1121 User
Manual for more information about the SCXI-1121.

©National Instruments Corporation 3 SCXI-1121 Calibration Procedure
Test Equipment
NI recommends that you use the equipment in Table 1 to calibrate the
SCXI-1121. If these instruments are not available, use the requirements
listed in Table 1 to select a suitable substitute.
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-1121 front and rear connectors.
Test Conditions
Follow these guidelines to optimize the connections and environment
during calibration:
• Keep connections to the SCXI-1121 short. Long cables and wires can
act as antennas, picking up extra noise and thermal offsets that affect
measurements.
• Use shielded copper wire for all cable connections to the SCXI-1121.
Use twisted-pair wire to eliminate noise and thermal offsets.
• Maintain the ambient temperature between 18 °C and 28 °C.
• Keep relative humidity below 80%.
• Allow a warm-up time of at least 15 minutes for the SCXI-1121 to
ensure that the measurement circuitry is at a stable operating
temperature.
Table 1. Test Equipment
Equipment
Recommended
Model Requirements
Calibrator Fluke 5700A 50 ppm
DMM NI 4070 5 1/2-digit, 15 ppm
Resistors — 120 Ωand 800 Ω, ±10%

SCXI-1121 Calibration Procedure 4 ni.com
Calibration Process
The calibration process has the following steps:
1. Initial Setup—Configure the SCXI-1121 for calibration.
2. Verification Procedure—Verify the existing operation of the
SCXI-1121. This step determines whether the SCXI-1121 is operating
within its test limits.
3. Adjustment Procedure—Perform an external calibration that adjusts
the SCXI-1121 calibration constants with respect to a known voltage
source.
4. Verifying Adjusted Values—Perform another verification to ensure
that the SCXI-1121 is operating within its test limits after adjustments.
Initial Setup
Complete the following steps to configure the SCXI-1121 for calibration.
Refer to Figure 1 for steps 1 and 2 and Figure 2 for steps 3 and 4.
1. Remove the grounding screw from the SCXI-1121.
2. Remove the cover on the SCXI-1121 so that you have access to the
potentiometers.
Figure 1. Grounding Screw and Module Cover Removal
1 Grounding Screw 2 Module Cover
1
2

©National Instruments Corporation 5 SCXI-1121 Calibration Procedure
3. Remove the side plate of the SCXI chassis.
4. Install the SCXI-1121 into the right-most slot of the SCXI chassis.
Figure 2. Side Plate Removal and Module Installation
You do not need to cable the SCXI-1121 to a DAQ device. Leave the
configuration of the digital jumpers W32, W38, and W45 unchanged
because they do not affect this calibration procedure.
Configuring the Half-Bridge Completion Jumpers
Verify that the half-bridge completion network is disabled prior to
calibrating the SCXI-1121. Refer to Figure 3 for the location of the
half-bridge completion jumpers. Refer to Table 2 for the correct jumper
settings to disable the completion network.
1 Thumbscrews 2 Right-Most Slot 3 Side Plate
23
MAINFRAME
SCXI
NATIONAL
INSTRUMENTS
1

SCXI-1121 Calibration Procedure 6 ni.com
Figure 3. SCXI-1121 Parts Locator Diagram
1 Thumbscrews
2 Voltage and Current Adjust
3 Front Connector
4 Serial Number
5 Output Null Adjust Potentiometers
6 Second-Stage Filter Jumpers
7 Rear Signal Connector
8 Product Name, Assembly Number, Revision Letter
9 SCXIbus Connector
10 Terminal Block Mounting Hole
11 Excitation Level Jumpers
12 First-Stage Filter Jumpers
13 Second-Stage Gain Jumpers
14 First-Stage Gain Jumpers
15 Half-Bridge Completion Jumpers
16 Input Null Adjust Potentiometers
17 Excitation Mode Jumpers
18 Grounding Screw
Q2
U4
U7
R3
W33
R2
W32
R6
R7
R12
R13
R16
R17
R26
C2 C3
W1
W3
W14
W15
W16
W17
W18
W19
W27
W28
W29
W36
Q3
Q5
Q6
Q9
Q14
D1
D2
D3 D4
D11
D14
D15 D16
U18
U24
U28
U31
U39
W26
R33
U35
R10
U15
C14
C30
Q13
R277
C24
C25
D9
U6
C18
C424
U38
R275
R276
U2
Q1 U1
U19
U20
C125
W31
W30
Q4
W21
U3
C42
U22
L1 L2
C22
C21
J2
R274
R1 R15 R25
R8
R35
W20
U17
W4
W5
R21
C19
D6
U14
D5
C26
W38
C85
R5
R4
C70
R28
R27
W35
R30
D23
C29
D29
D38
R29
D22
D37
D28
U36
R32
R31
W34
Q20D34
W49
J1
R22
W24
R18
U25
W23
W22
Q7
R20
R19
D10
C36
W6
W8
W9
W10
W11
W12
W13
U40
D7
D21
D17
Q18
D39
C37
D30
Q16 Q17
C423
C15
C39
C38
R45
C33
D13
W25
C20
R46 C143
U51
D40
R281
W45
U61
R99
U27
U33
U9U8
R11
U21
C27
D41
U37
Q21
U48
U60
U50
C34
D19 D20
C425
U5
C16
D18
D26
D27
D36
D35
U47
U46
C32
R23
U11
C105
D12 Q8
U30
U42
D25 Q12
D24 Q11
U41
U34
U16
R9
U10
U23
U29
Q10
W2
W7
U44
U32
W37
U26
c
+
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S/N
AD705
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AD705
ISO122P
ISO122P
1
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HCT08 HCT00 HC05
11
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1111
1
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B
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LF347
GAINDIP
PRIMARY
PRIMARY
GAINDIP
RES
20K
RES
20K
RES
20K
DG409
34182
MC
34182
MC
34072
MC
GAINDIP
34072 MC
AD705
34072
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34072 MC
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COPYRIGHT 1996
RES
20K
MC
34080
CD4047
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LT-
1009
HCT03
HCT240
HCT273
ASSY181505F-01
SCXI-1121
HCT165
9
1
3
1
5
R42
R43
W41
Q19
R40
W42
W43
D32
D31
D33
R41
R38
R37
U43
W48W47
R39
U45
AD705
GAINDIP
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AD705
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R36
W39
W40
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W46
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W40 W41
W42
W43
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R36
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Front Rear
15
18

©National Instruments Corporation 7 SCXI-1121 Calibration 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. The SCXI-1121 ships with the first-stage gain
set to 100 (position A) and the second-stage gain set to 10 (position D).
To change the gain setting of a specified channel on the SCXI-1121, refer
to Table 3 for the gain jumper reference designators. Refer to Figure 3 for
the location of the gain jumpers. Move the jumper to the position indicated
in Table 4.
Table 2. Completion Network Jumpers
Channel Jumpers
Enable
Completion
Disable Network
(Factory Setting)
0W1 and W2
1W17 and
W18
l
2W27 and
W28
3W39 and
W40
A B
W2
W1
1 2 3
A B
W2
W1
1 2 3
W18
A B
W17
1 2 3
W18
A B
W17
1 2 3
W28
A B
W27
1 2 3
W28
A B
W27
1 2 3
W40
A B
W39
1 2 3
W40
A B
W39
1 2 3

SCXI-1121 Calibration Procedure 8 ni.com
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 equals the
desired final gain value.
Configuring the Filter Jumpers
Each input channel also has two user-configurable filter stages. The
SCXI-1121 ships in the 4 Hz position. Refer to Table 5 for the correct
jumper setting for the desired cutoff frequency. Refer to Figure 3 for the
locations of the jumper blocks on the SCXI-1121. Verify that both filter
stages are set to the same filter setting to ensure that you achieve the desired
bandwidth.
Table 3. Gain Jumper Reference Designators
Input Channel
Number
First-Stage
Gain Jumper
Second-Stage
Gain Jumper
0W3 W4
1W19 W20
2W29 W30
3W41 W42
Table 4. Gain Jumper Positions
Gain Setting Jumper Position
First-Stage 1 D
10 C
50 B
100 A (factory setting)
Second-Stage 1 A
2 B
5 C
10 D (factory setting)
20 E

©National Instruments Corporation 9 SCXI-1121 Calibration Procedure
Configuring the Excitation Jumpers
You can configure each excitation channel of the SCXI-1121 to either a
voltage or current excitation mode. Each channel has two jumpers for this
purpose. Set both jumpers in the same mode for correct operation of the
excitation channel. Refer to Table 6 to determine how to set up the
SCXI-1121 in the desired mode. The SCXI-1121 ships to you in the voltage
mode.
Table 5. Filter Jumper Settings
Input
Channel
Number
First Filter Jumper Second Filter Jumper
4 Hz
(Factory
Setting) 4 kHz
4 Hz
(Factory
Setting) 4 kHz
0W5-A W5-B W6 W7
1W21-A W21-B W8 W9
2W31-A W31-B W10 W11
3W43-A W43-B W12 W13
Table 6. Voltage and Current Mode Excitation Jumper Settings
Excitation
Channel Jumpers
Volta g e M o de
(Factory Setting) Current Mode
0W14 and
W15
1W22 and
W23
2W34 and
W35
3W46 and
W47
W14
1 2 3
W15
1 2 3
W14
1 2 3
W15
1 2 3
W22
1 2 3
W23
1 2 3
W22
1 2 3
W23
1 2 3
W34
1 2 3
W35
1 2 3
W34
1 2 3
W35
1 2 3
W46
1 2 3
W47
1 2 3
W46
1 2 3
W47
1 2 3

SCXI-1121 Calibration Procedure 10 ni.com
Configuring the Excitation Level
Each excitation channel of the SCXI-1121 has two different current or
voltage levels. You can set a given channel to one of the following levels:
• In the current mode—0.150 mA or 0.450 mA
• In the voltage mode—3.333 V or 10 V
After selecting the excitation mode of the desired operation—voltage or
current, refer to Table 7 to set the SCXI-1121 for the level of operation. The
SCXI-1121 ships with the voltage mode set to 3.333 V.
Verification Procedure
The verification procedure determines how well the SCXI-1121 is meeting
its test limits. You can use this information to select the appropriate
calibration interval for your application.
Verifying Analog Input Offsets
Complete the following steps to verify the analog input offsets:
1. Refer to Table 12 in the Test Limits section for all acceptable settings
for the SCXI-1121. NI recommends verifying all ranges and gains, but
you can save time by checking only those ranges used in your
application.
Table 7. Excitation Level Jumper Settings
Excitation
Channel Jumpers
3.333 V or
0.150 mA
(Factory Setting) 10 V or 0.450 mA
0W16 and
W26
1W24 and
W25
2W36 and
W37
3W48 and
W49
W16
1 2 3
1
2
3
W26
W16
1 2 3
1
2
3
W26
W24
1 2 3
W25
1 2 3
W24
1 2 3
W25
1 2 3
W36
1 2 3
W37
1 2 3
W36
1 2 3
W37
1 2 3
W48
1 2 3
W49
1 2 3
W48
1 2 3
W49
1 2 3

©National Instruments Corporation 11 SCXI-1121 Calibration Procedure
2. Set the channel gain on all channels to the gain you want to test,
starting with the smallest gain available for the SCXI-1121. Refer to
Table 12 for available gains.
3. Set the channel filter for all channels on the SCXI-1121 to 10 kHz.
4. 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 13 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–.
5. Set the DMM to voltage mode, and connect it to the output of the same
channel to which the calibrator was connected in step 4. Refer to
Table 14 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 CH 0+. The negative output for channel 0 is pin 4, which is
labeled CH 0–.
6. Set the calibrator voltage to the value specified by the Test Point entry
listed in Table 12.
7. Read the resulting output voltage on the DMM. If the output voltage
result falls between the Upper Limit and the Lower Limit values, the
SCXI-1121 passed the test.
8. Repeat steps 4 through 7 for the remaining test points.
9. Repeat steps 4 through 8 for the remaining analog input channels.
10. Repeat steps 2 through 9 for the remaining gain and filter values
specified in Table 12.
You have completed verifying the analog input offsets. If any of your
measurements fall outside the test limits listed in Table 12, adjust the
SCXI-1121 as described in the Adjusting Analog Input Offsets section.
Verifying Voltage Excitation Limits
Complete the following steps to verify the voltage excitation limits:
1. Connect a 120 Ω resistor to the output of the excitation channel you are
testing, starting with excitation channel 0.
If you have a terminal block such as the SCXI-1320, the excitation
channel connections are marked on the terminal block. If you do not
have a terminal block, refer to Table 13 for connection information.
2. Configure the excitation channel to the 3.333 V level.
3. Set the DMM to voltage mode, and connect the DMM leads to the
excitation output as closely as possible to the resistor body.

SCXI-1121 Calibration Procedure 12 ni.com
4. Compare the DMM reading to the limits for excitation shown in
Table 8. If the reading falls between the Upper Limit and the Lower
Limit values, the SCXI-1121 passed the test.
5. Configure the excitation channel to the 10 V level, replace the 120 Ω
resistor with the 800 Ωresistor, and repeat steps 3 and 4.
6. Repeat steps 2 through 5 for all remaining channels.
You have completed verifying the voltage excitation limits. If any of your
measurements fall outside the test limits listed in Table 8, adjust the
SCXI-1121 as described in the Adjusting Voltage Excitation section.
Verifying Current Excitation Limits
Complete the following steps to verify current excitation limits:
1. Remove the resistor from the excitation channel if you have not
already done so.
2. Configure the channel to the 0.150 mA excitation level.
3. Set the DMM to current mode, and connect it to the excitation channel
output, starting with excitation channel 0.
If you do not have a terminal block, refer to Figure 3 for connection
information.
4. Compare the DMM reading to the limits for excitation shown in
Table 9. If the reading falls between the Upper Limit and Lower Limit
values, the SCXI-1121 passed the test.
5. Configure the channel for 0.450 mA excitation level and repeat
steps 2 and 4.
6. Repeat steps 2 through 5 for all remaining channels.
Table 8. SCXI-1121 Voltage Excitation Limits
Test Point (V) Upper Limit (V) Lower Limit (V)
3.333 3.334333 3.331667
10 10.020000 9.980000
Table 9. SCXI-1121 Current Excitation Limits
Test Poin t ( m A ) Upper Limit (mA) Lower Limit (mA)
0.150 0.150060 0.149940
0.450 0.450900 0.449100

©National Instruments Corporation 13 SCXI-1121 Calibration Procedure
You have completed verifying the current excitation limits. If any of your
measurements fall outside the limits listed in Table 9, adjust the SCXI-1121
as described in the Adjusting Current Excitation section.
Adjustment Procedure
The adjustment procedure adjusts the analog input offsets, the voltage
excitation limits, and the current excitation limits.
Adjusting Analog Input Offsets
Complete the following steps to adjust the offset null value:
1. Set the channel gain on the channel you are adjusting to a gain of 1.
Set the filter value to 4 Hz.
2. Connect the calibrator to the analog input channel you want to adjust.
Refer to Table 13 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. Set the DMM to voltage mode, and connect it to the output of the same
channel to which the calibrator was connected in step 2. Refer to
Table 14 to determine the pins on the 50-pin rear connector that
corresponds to the positive and negative outputs for the specified
channel. For example, the positive output for channel 0 is pin 3, which
is labeled CH 0+. The negative output for channel 0 is pin 4, which is
labeled CH 0–.
4. Set the calibrator voltage to 0.0 V.
5. Adjust the output null potentiometer of the channel until the DMM
reading is 0.0 ±3.0 mV. Refer to Figure 3 for the potentiometer
location and Table 10 for the potentiometer reference designator.
6. Set the channel gain to a gain of 1000.0 on the channel you are
adjusting. Refer to Tables 3, 4, and 5 for more information.
Table 10. Calibration Potentiometers Reference Designators
Input Channel Number Input Null Output Null
0R02 R03
1R16 R04
2R26 R05
3R36 R06

SCXI-1121 Calibration Procedure 14 ni.com
7. Adjust the input null potentiometer of channel 0 until the DMM
reading is 0.0 ±6.0 mV. Refer to Figure 3 for the potentiometer
location and Table 10 for the potentiometer reference designator.
8. Repeat steps 1 through 7 for the remaining analog inputs.
You have completed adjusting the analog input offsets.
Adjusting Voltage Excitation
When you adjust the excitation channels, always start with the voltage
excitation and then proceed to the current excitation. Use the voltage
excitation reference as the voltage reference for the current excitation.
Complete the following steps to adjust the voltage excitation:
1. Connect the 120 Ω resistor across the output of the excitation channel
you are adjusting.
2. Configure the excitation channel to 3.333 V excitation level.
3. Set the DMM to voltage mode, and connect the DMM leads to the
excitation outputs as closely as possible to the resistor body.
4. Adjust the excitation voltage potentiometer until the voltage reading
falls between 3.334333 V and 3.331667 V. Refer to Figure 3 for the
potentiometer location and Table 11 for the potentiometer reference
designator.
Note This step calibrates the 10 V excitation level at the same time, but the accuracy
achieved is limited to ±0.2%. To achieve better accuracy at the 10 V level, follow steps 1
through 4 but set the excitation level to 10 V instead of 3.333 V. If you do so, the 3.333 V
level of this channel will then be calibrated to ±0.2% instead of to ±0.04%. In the factory,
the SCXI-1121 is calibrated for 3.333 V.
5. Repeat steps 1 through 4 for all remaining channels.
You have completed adjusting the voltage excitation channels.
Table 11. Excitation Calibration Potentiometer Reference Designators
Input Channel
Number
Excitation Channel
Voltage Mode Current Mode
0R10 R7
1R20 R17
2R30 R27
3R40 R37

©National Instruments Corporation 15 SCXI-1121 Calibration Procedure
Adjusting Current Excitation
Complete the following steps to adjust the current excitation:
1. Remove the resistor from the excitation channel if you have not
already done so.
2. Configure the channel for 0.150 mA current excitation level.
3. Set the DMM to current mode, and connect it to the excitation channel
output you want to adjust.
4. Adjust the excitation current potentiometer until the current reading
falls between 0.150060 mA and 0.149940 mA. Refer to Figure 3 for
the potentiometer location and Table 11 for the potentiometer
reference designator.
Note This step calibrates the 450 µA level at the same time, but the accuracy achieved is
limited to ±0.2%. To achieve better accuracy at the 450 μA level, follow steps 1 through 4
but set the excitation level to 450 µA instead of 150 µA. If you do so, the 150 µA level of
this channel will then be calibrated to ±0.2% instead of to ±0.04%. In the factory, the
SCXI-1121 is calibrated for 150 µA.
5. Repeat steps 1 through 4 for all remaining channels.
You have completed adjusting the current excitation channels.
Verifying Adjusted Values
After completing the adjustments, it is important to verify the analog
input operation, the voltage excitation, and the current excitation again by
repeating the steps listed in the Verification Procedure. Verifying the
adjusted values ensures that the SCXI-1121 is operating within its test
limits after adjustments.
Note If the SCXI-1121 fails after calibration, return it to NI for repair or replacement. For
more information about how to contact NI for repair or replacement, refer to the Technical
Support Information document.

SCXI-1121 Calibration Procedure 16 ni.com
Test Limits
Table 12 contains test limits for the SCXI-1121. If the module was
calibrated within the last year, the output should fall between the Upper
Limit and Lower Limit values.
Table 12. SCXI-1121 Test Limits
Gain Test Po int (V)
4 Hz Filter Setting 10 kHz Filter Setting
Upper
Limit (V)
Lower
Limit (V)
Upper
Limit (V)
Lower
Limit (V)
0.01*225.0000 2.269765 2.230236 2.346618 2.303382
0.01*0.0000 0.005144 –0.05144 0.006510 –0.006510
0.01*–225.0000 –2.230236 –2.269765 –2.303382 –2.346618
0.02*225.0000 4.534387 4.465613 3.750713 3.689287
0.02*0.0000 0.005146 –0.005146 0.006540 –0.006540
0.02*–225.0000 –4.465613 –4.534387 –3.689287 –3.750713
0.05*90.0000 4.534387 4.465614 4.686836 4.613164
0.05*0.0000 0.005146 –0.005146 0.006620 –0.006620
0.05*–90.0000 –4.465614 –4.534387 –4.613164 –4.686836
0.01*45.0000 4.534387 4.465613 4.686936 4.613064
0.01*0.0000 0.005146 –0.005146 0.006720 –0.006720
0.01*–45.0000 –4.465613 –4.534387 – 4.613064 –4.686936
0.02*22.5000 4.534387 4.465613 4.687516 4.612484
0.02*0.0000 0.005146 –0.005146 –0.007300 –0.007300
0.02*–22.5000 –4.465613 –4.534387 –4.612484 –4.687516
0.05*9.0000 4.534388 4.465613 4.686911 4.613089
0.05*0.0000 0.005147 –0.005147 0.006695 –0.006695
0.05*–9.0000 –4.465613 –4.534388 –4.613089 –4.686911
14.5000 4.534295 4.465705 4.535671 4.464329
10.0000 0.005144 –0.005144 0.006520 –0.006520
1–4.5000 –4.465705 –4.534295 –4.464329 –4.535671
22.2500 4.534292 4.465708 4.535693 4.464307
20.0000 0.005141 –0.005141 0.006542 –0.006542
2–2.2500 –4.465708 –4.534292 –4.464307 –4.535693

©National Instruments Corporation 17 SCXI-1121 Calibration Procedure
50.9000 4.534293 4.465707 4.535706 4.464294
50.0000 0.005142 –0.005142 0.006555 –0.006555
5–0.9000 –4.465707 –4.534293 –4.464294 –4.535706
10 0.4500 4.534387 4.465613 4.535771 4.464229
10 0.0000 0.005236 –0.005236 0.006620 –0.006620
10 –0.4500 –4.465613 –4.534387 –4.464229 –4.535771
20 0.2250 4.534456 4.465544 4.535979 4.464021
20 0.0000 0.005305 –0.005305 0.006828 –0.006828
20 –0.2250 –4.465544 –4.534456 –4.464021 –4.535979
50 0.0900 4.534694 4.465306 4.536146 4.463854
50 0.0000 0.005543 –0.005543 0.006995 –0.006995
50 –0.0900 –4.465306 –4.534694 –4.463854 –4.536146
100 0.0450 4.535095 4.464905 4.536551 4.463449
100 0.0000 0.005944 –0.005944 0.007400 –0.007400
100 –0.0450 –4.464905 –4.535095 –4.463449 –4.536551
200 0.0225 4.535892 4.464108 4.537797 4.462203
200 0.0000 0.006741 –0.006741 0.008646 –0.008646
200 0.0225 –4.464108 –4.535892 –4.462203 –4.537797
250 0.0180 4.536294 4.463706 4.538614 4.461387
250 0.0000 0.007143 –0.007143 0.009463 –0.009463
250 –0.0180 –4.463706 –4.536294 –4.461387 –4.538614
500 0.0090 4.538303 4.461698 4.540951 4.459049
500 0.0000 0.009152 –0.009152 0.011800 –0.011800
500 –0.0090 –4.461698 –4.538303 –4.459049 –4.540951
1000 0.0045 4.542321 4.457679 4.546501 4.453499
1000 0.0000 0.013170 –0.013170 0.017350 –0.017350
1000 –0.0045 –4.457679 –4.542321 –4.453499 –4.546501
2000 0.00225 4.551389 4.448611 4.558631 4.441369
Table 12. SCXI-1121 Test Limits (Continued)
Gain Test Po int (V)
4 Hz Filter Setting 10 kHz Filter Setting
Upper
Limit (V)
Lower
Limit (V)
Upper
Limit (V)
Lower
Limit (V)

SCXI-1121 Calibration Procedure 18 ni.com
2000 0.00000 0.022238 –0.022238 0.029480 –0.029480
2000 –0.00225 – 4.448611 –4.551389 –4.441369 –4.558631
*Value available only when used with the SCXI-1327 high-voltage terminal block
Table 12. SCXI-1121 Test Limits (Continued)
Gain Test Po int (V)
4 Hz Filter Setting 10 kHz Filter Setting
Upper
Limit (V)
Lower
Limit (V)
Upper
Limit (V)
Lower
Limit (V)

©National Instruments Corporation 19 SCXI-1121 Calibration Procedure
SCXI-1121 Front and Rear Panel Diagrams
Table 13 shows the pin assignments for the SCXI-1121 front panel
connector. Table 14 shows the pin assignments for the SCXI-1121 rear
signal connector.

SCXI-1121 Calibration Procedure 20 ni.com
Table 13. Front Connector Pin Assignments
Front Connector Diagram Pin Number Column A Column B Column C
NC—No Connection
32 CH0+ NC CH0–
31 NC NC NC
30 EX0+ NC EX0–
29 NC NC NC
28 EGND0 NC NC
27 NC NC NC
26 CH1+ NC CH1–
25 NC NC NC
24 EX1+ NC EX1–
23 NC NC NC
22 EGND1 NC NC
21 NC NC NC
20 CH2+ NC CH2–
19 NC NC NC
18 EX2+ NC EX2–
17 NC NC NC
16 EGND2 NC NC
15 NC NC NC
14 CH3+ NC CH3–
13 NC NC NC
12 EX3+ NC EX3–
11 NC NC NC
10 EGND3 NC NC
9NC NC NC
8NC NC RSVD
7NC NC NC
6SCAL NC RSVD
5NC NC NC
4+5V NC MTEMP
3NC NC NC
2CGND NC DTEMP
1NC NC NC
Column
A B C
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
7
6
5
4
3
2
1