National Instruments Module SCXI-1503 Manual

CALIBRATION PROCEDURE
SCXI -1503
This document contains information for verifying and adjusting the SCXI-1503 module using
NI-DAQmx 8.1 or later. For more information about calibration, visit ni.com/calibration.
Contents
Software Requirements........................................................................................................................ 1
Documentation Requirements.............................................................................................................. 2
Calibration Interval .............................................................................................................................. 2
Test Equipment .................................................................................................................................... 3
Test Conditions .................................................................................................................................... 3
Calibration Procedures......................................................................................................................... 4
Initial Setup.................................................................................................................................. 5
Self-Calibration............................................................................................................................ 8
MAX .................................................................................................................................... 8
Verification .................................................................................................................................. 8
Verifying the Analog Input.................................................................................................. 8
Verifying the Excitation Current ......................................................................................... 11
Adjustment................................................................................................................................... 11
Adjusting the Analog Input.................................................................................................. 12
Adjusting the Excitation Current ......................................................................................... 14
Where to Go for Support ..................................................................................................................... 15
Software Requirements
Calibrating the SCXI-1503 requires installing NI-DAQmx 8.1 or later on the calibration system.
You can download NI-DAQmx from ni.com/downloads. NI-DAQmx 8.1 or later supports
self-calibration and external calibration in the LabVIEW, LabWindows/CVI, C/C++, C#, and
Visual Basic .NET application development environments (ADEs). When you install NI-DAQmx 8.1 or
later, you only need to install support for the ADE that you intend to use.
™
ni.com/manuals
DeutschFrançais

SCXI-1503 Calibration Procedure 2 ni.com
Documentation Requirements
For information about NI-DAQmx, and the SCXI-1503 module and SCXI-1306 terminal block, consult
the following documents:
•SCXI Quick Start Guide—provides instructions for installing and configuring SCXI chassis and
modules.
•SCXI-1503 User Manual (includes specifications)—includes detailed information and published
specifications for the SCXI-1503.
•SCXI-1306 Terminal Block Installation Guide—includes detailed information and published
specifications for the SCXI-1306.
•NI-DAQmx Help—includes information about creating applications that use NI-DAQmx.
•NI-DAQmx C Reference Help—includes information about the functions in the driver.
You can find the latest versions of the documentation at ni.com/manuals.
Calibration Interval
National Instruments recommends a calibration interval of one year for the SCXI-1503. You should
adjust the recommended calibration interval based on the measurement accuracy demands of your
application.

©National Instruments 3 SCXI-1503 Calibration Procedure
Test Equipment
National Instruments recommends using the equipment in Table 1 for adjusting and verifying the
SCXI-1503.
Test Conditions
The following setup and environmental conditions are required to ensure the SCXI-1503 meets
published specifications.
• Keep connections to the module as short as possible. Long cables and wires act as antennae, which
can pick up extra noise that affects measurements.
• Verify that all connections to the calibration system are secure.
• Maintain an ambient temperature of 25 ±10 °C. The SCXI-1503 module temperature will be
greater than the ambient temperature. If you plan to operate the SCXI-1503 at a specific
temperature outside this range, calibrate the module at that temperature.
• Keep relative humidity below 80%.
Table 1. Recommended Equipment
Equipment
Recommended
Model
Parameter
Measured Minimum Requirements
Calibrator Fluke 5500A* Analog Input If this instrument is
unavailable, use a
calibrator that is accurate to
10 ppm (5 digits).
DMM PXI-4071 Excitation Current
Analog Input
If this instrument is
unavailable, use a
multiranging 7½ digit
DMM.
SCXI Chassis SCXI-1000 — —
DAQ Device NI PCI(e)/PXI(e) E, M
or X Series Device
—16-bit DAQ device
that is supported by
NI-DAQmx 8.1 or later.
Terminal Block Connection
Accessory
SCXI-1306 — —
Rear Connection Accessory SCXI-1349 — —
Terminal Accessory, 50-pin CB-50 — —
Ribbon Cable, 50-Pin NB1 — —
Cable between SCXI-1349
and E Series DAQ devices
SH68-68-EP — —
Cable between SCXI-1349
and M Series or X Series
DAQ devices
SHC68-68-EPM — —
* If using the Fluke 5500A calibrator, you must have the Fluke Fl5xmcal driver installed on the test computer.

SCXI-1503 Calibration Procedure 4 ni.com
• Allow a warm-up time of at least 30 minutes to ensure that the measurement circuitry is at a stable
operating temperature.
• Use shielded copper wire for all cable connections to the SCXI-1306 terminal block. Use
twisted-pair wire to eliminate noise and thermal offsets.
• Ensure that the SCXI chassis empty slots contain front and rear filler panels.
• Plug the SCXI chassis, computer, and the instrument standard into the same power strip to avoid
ground loops.
Calibration Procedures
The calibration process includes the following steps:
1. Initial Setup—Install the module and configure it in Measurement & Automation Explorer (MAX).
2. Self-Calibration—Adjust the self-calibration constants of the module.
3. Verification—Verify the existing operation of the module. This step confirms whether the module
is operating within the published specifications prior to adjustment.
4. Adjustment—Adjust the calibration constants of the module. The adjustment procedure
automatically stores the calibration date on the EEPROM. Go to ni.com/calibration for
information about returning a module to NI for a factory calibration.
5. Reverification—Repeat the verification procedure to ensure that the module is operating within the
published specifications after adjustment.
These procedures are described in more detail in the following sections.

©National Instruments 5 SCXI-1503 Calibration Procedure
Initial Setup
Refer to the DAQ Getting Started Guides and the SCXI Quick Start guide for information about how to
install the software and hardware, and how to configure the module in MAX. Figure 1 shows a typical
SCXI setup for calibration using an NI PCI(e) DAQ device.
Figure 1. Typical Setup for Verification and Adjustment Using an NI PCI(e) DAQ Device
1 SCXI-1306 Terminal Block
2 SCXI-1503 Module
3 SCXI-1000 Chassis
4 SCXI-1349 Adapter
5 SH68-68 EP Cable (for E Series DAQ Device)
SHC68-68 EPM Cable (for M or X Series DAQ Device)
6 Test Computer, with NI PCI(e) DAQ Device
7DMM
8Calibrator
9 Calibrator to SCXI-1306 Wiring
10 CB-50 to DMM Wiring
11 CB-50 Terminal Accessory
12 NB1 Ribbon Cable
+10.0000208 V
+10.0000001 V DC
,
DCV ACVOHM DCI ACI FREQ
Local




Auto
Cal
Auto
Zero
Trig
Recall
State
NPLC
Offset
Comp
NRdg/
Trig
Store
State
On
Off
7.000
kHz
7
10
SCXI 1100
2468 1012 14 16 18 20 20 24 26 28 30 32 34 36 38 40 42 44 46 48 50
13 5 7 911131517 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49
1
2
8
®
5
4
3
2
1
ADDRESS
3
9
4
6
11
12
5

SCXI-1503 Calibration Procedure 6 ni.com
Figure 2 shows a typical SCXI setup for calibration using the NI PXI(e) DAQ device.
Figure 2. Typical Setup for Verification and Adjustment Using an NI PXI(e) DAQ Device
1. Power off the SCXI-1000 chassis.
2. Insert the SCXI-1503 into any available SCXI-1000 chassis slot.
Note If you are using an NI PCI(e) DAQ device, connect the SCXI-1349 to the NI PCI(e) DAQ
device using an SHC68-68 cable.
Note If you are using an NI PXI(e) DAQ device rather than an NI PCI(e) DAQ device, refer to
Figure 2 to make your connections.
1 SCXI-1306 Terminal Block
2 SCXI-1503 Module
3 SCXI-1000 Chassis
4 SCXI-1349 Adapter
5 SHC68-68 EPM Cable
6 PXI Chassis
7DMM
8 Calibrator
9 Calibrator to SCXI-1306 Wiring
10 CB-50 to DMM Wiring
11 CB-50 Terminal Accessory
12 NB1 Ribbon Cable
+10.0000208 V
+10.0000001 V DC
,
DCVACV OHMDCIACIFREQ
Local




Auto
Cal
Auto
Zero
Trig
Recall
State
NPLC
Offset
Comp
NRdg/
Trig
Store
State
On
Off
7.000
kHz
SCXI 1100
2468101214 16 18 20 20 24 26 28 30 32 34 36 38 40 42 44 46 48 50
13 5 7 911 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49
1
2
7
5
8
3
9
10
4
11
NI PXIe-1062Q
5
4
3
2
1
ADDRESS
12
6
NATIONAL
INSTRUMENTS

©National Instruments 7 SCXI-1503 Calibration Procedure
3. Ensure that all of the SCXI-1306 configuration switches are switched to the off position, as shown
in Figure 3.
Figure 3. SCXI-1306 Switch Diagram
4. Install the SCXI-1306 on the SCXI-1503 DUT.
5. Power on the SCXI-1000 chassis.
1 Configuration Switches (shown in Off position) 2 Switch Legends 3 Ground Lug
1 2 1 1 2 1
ON = Closed
IEX+/AI+ IEX–/AI–
Ch X
IEX+
AI+
AI–
IEX–
IEX+
AI+
AI–
IEX–
CH 0CH 1 CH 2CH 3 CH 4CH 5 CH 6CH 7
CH 9CH 8
CH 11CH 10
CH 13CH 12
CH 15CH 14
1 2 34 5 6 7 81 2 34 5 6 7 8
CH 4 CH 5 CH 6 CH 7CH 0 CH 1 CH 2 CH 3CH 12 CH 13CH 14 CH 15
CH 8CH 9 CH 10 CH 11
ON ON
SW 1 SW 2 ON ON SW 3SW 4
1
1 2 34 5 6 7 81 2 34 5 6 7 8
3
1 2 34 5 6 7 8
CH 0 CH 1 CH 2 CH 3
ON

SCXI-1503 Calibration Procedure 8 ni.com
Self-Calibration
The SCXI-1503 includes precise internal circuits and references used during self-calibration to adjust
for any errors caused by short-term fluctuations in the environment.
Note Allow a 30 minute warm-up period before you begin self-calibration.
You can initiate self-calibration from MAX.
MAX
To initiate self-calibration from MAX, complete the following steps:
1. Launch MAX.
2. Select My System»Devices and Interfaces»NI-DAQmx Devices.
Note NI-DAQmx Devices is not displayed when using NI-DAQmx 9.0 or later.
3. Select the DAQ device you are using to digitize the SCXI-1503.
4. Initiate self-calibration in one of the following ways:
•ClickSelf-Calibrate in the upper right corner of the window. If the Self-Calibrate button is
not displayed, click the »button.
• Right-click the module and select Self-Calibrate from the context menu.
5. Select the chassis containing the module you want to calibrate.
6. Select the module that you want to calibrate.
7. Initialize a self-calibration of the module you want to calibrate.
Verification
This section provides instructions for verifying the following SCXI-1503 specifications:
• Analog input.
• Excitation current.
Note Limits in Table 2 are based on the March 2007 edition of the SCXI-1503 User Manual, which
includes the specifications. Refer to ni.com/manuals to determine if there is a more recent edition
of the specifications. If a more recent edition of the specifications is available, recalculate the limits
based upon the latest specifications.
Verifying the Analog Input
Complete the following steps to verify the analog input of the SCXI-1503:
1. Connect the calibrator ± output to all of the SCXI-1306 AI± input channels.
Note Ensure that all switches on the SCXI-1306 are in the off position as shown in Figure 3.
2. Insert the NB1 ribbon cable into the breakout connector on the SCXI-1349.
3. Insert the SCXI-1349 into the SCXI-1503 rear connector.
4. Insert the other end of the NB1 ribbon cable into the CB-50 ribbon cable connector.

©National Instruments 9 SCXI-1503 Calibration Procedure
5. Connect the DMM V+ to pin 3 and DMM V- to pin 4 of the CB-50 terminal accessory. Refer to
Figure 4 for pin locations.
Figure 4. CB-50 Terminal Accessory Wiring Diagram for Connection to DMM
6. Configure an AI voltage channel with an input range of ±10 V for channel ai0 on the
NI PCI(e)/PXI(e) DAQ device.
7. Use DAQmx properties to read the AI dev scaling coefficients of the DAQ device. E Series have
two scaling coefficients while M Series and X Series have four scaling coefficients. Record the
first two scaling coefficients and save the values as a0and a1.
Note The DAQ device scaling coefficients, a0and a1, are the same for each channel on the SCXI
module since the DAQ device multiplexes all SCXI channels to channel ai0 on the DAQ device.
8. Clear the task.
1 To DMM V+
2 To DMM V-
3 NB1 Ribbon Cable Connector
4 CB-50 Top View
5 CB-50 Side View
5048464442403836343230282624222018161412108642
494745434139373533312927252321191715131197531
3
5
2
4
5
1
5
2
1

SCXI-1503 Calibration Procedure 10 ni.com
9. Configure the calibrator to output a DC voltage. Table 2 shows the test point values.
10. Create an AI voltage channel with an input range of ±10 V for one channel on the SCXI-1503.
11. Configure the SCXI-1503 input channel for a finite acquisition with a sample rate of 1000 Hz and
1000 samples per channel.
12. Use DAQmx properties to set a gain of 1.
13. Use DAQmx properties to read the DAQ device scaling coefficients. E Series have two scaling
coefficients while M Series and X Series have four scaling coefficients. Record the first two scaling
coefficients and save the values as b0and b1.
14. Start the task to set the channel MUX to the specified channel.
15. Use the saved device scaling coefficients from the DAQ device, a0and a1from step 7, and the
combined DAQ device and SCXI-1503 module, b0and b1from step 13, to compute the device
scaling coefficients for just the SCXI-1503, c0and c1.
16. Configure the DMM to measure voltage at the CB-50 outputs and take a measurement.
Table 2. Test Point and Limit
SCXI-1503 Gain Test Point Level (V) Lower Limit (V) Upper Limit (V)
1 9 8.991680513 9.008319487
65.993900513 6.006099487
32.996120513 3.003879487
0-0.001659487 0.001659487
-3 -3.003879487 -2.996120513
-6 -6.006099487 -5.993900513
-9 -9.008319487 -8.991680513
100 0.09 0.089898305 0.090101695
0.06 0.059920505 0.060079495
0.03 0.029942705 0.030057295
0-0.0000350949 0.0000350949
-0.03 -0.030057295 -0.029942705
-0.06 -0.060079495 -0.059920505
-0.09 -0.090101695 -0.089898305
c0b0b1
a1
-----– a0 =
c1b1
a1
-----=