National Instruments Eight-slot USB Chassis NI cDAQ-9172 Manual

CALIBRATION PROCEDURE
cDAQ Chassis and Controllers
This document contains information for calibrating NI CompactDAQ (cDAQ-913x/917x/
918x/919x) chassis and controllers. For more information about calibration, visit ni.com/
calibration.
Software Requirements
Calibrating cDAQ chassis and controllers requires the installation of NI-DAQmx on the
calibration system. NI recommends using the latest NI-DAQmx driver. Refer to the
NI-DAQmx Readme to ensure support for the chassis or controller you want to calibrate, as
well as for the C Series digital module you are using. You can download NI-DAQmx from
ni.com/downloads. NI-DAQmx supports many 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 cDAQ chassis and controllers,
C Series modules, and the NI-DAQmx driver. All documents are available on ni.com/manuals;
help files install with the software.
Quick start for your cDAQ chassis or controller
The quick start provides instructions for installing and configuring your cDAQ
chassis or controller and C Series module.1
User manual for your cDAQ chassis or controller
The user manual provides information about your cDAQ chassis or controller.2
1The NI cDAQ-9172 User Guide and Specifications provides instructions for installing and
configuring your cDAQ-9172 and C Series module.
2The NI cDAQ-9172 User Guide and Specifications provides information about the cDAQ-9172
chassis.

Specifications for your cDAQ chassis or controller
The specifications provides detailed specifications for your cDAQ chassis or
controller.3
Getting started guide for your C Series module
The getting started guide for your C Series module provides information about
wiring to your C Series digital module.
NI-DAQmx Readme
Provides operating system and application software support in NI-DAQmx.
NI-DAQmx Help
Provides information about creating applications that use the NI-DAQmx driver.
NI-DAQmx C Reference Help
Provides reference information for NI-DAQmx C functions and NI-DAQmx
C properties.
Calibration Interval
NI recommends a calibration interval of one year for cDAQ chassis and controllers. Adjust the
recommended calibration interval based on the measurement accuracy demands of your
application.
Test Equipment
The following table lists the equipment required for calibrating your chassis or controller. If
you do not have the recommended instruments, use the minimum requirements to select
substitute equipment.
Table 1. Recommended Test Equipment
Equipment Recommended Models Minimum Requirements
Counter Keysight 53131A/53220A Counter accuracy to ±5 ppm
C Series Digital Module NI 9401 or NI 9402 —
3The NI cDAQ-9172 User Guide and Specifications provides detailed specifications for the
cDAQ-9172 chassis.
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Table 1. Recommended Test Equipment (Continued)
Equipment Recommended Models Minimum Requirements
(NI 9401) Front-Mounted
Terminal Block
NI 9924 or NI 9934 Terminal block for 25-pin DSUB
modules
(NI 9401) BNC-to-Leads
Cable
— BNC male-to-leads cable with a
length suitable for the application
(NI 9402) BNC Cable NI part number 781887-01 BNC male-to-BNC male cable with
a length suitable for the application
Test Conditions
The following setup and environmental conditions are required to ensure the cDAQ chassis or
controller meets published specifications:
• Keep connections to the C Series digital module as short as possible. Long cables and
wires act as antennas, picking up extra noise that can affect measurements.
• Maintain an ambient temperature of 23 °C ± 5 °C. The cDAQ chassis/controller
temperature will be greater than the ambient temperature.
• Keep relative humidity below 90%.
• Allow a warm up time of at least 10 minutes to ensure that the cDAQ chassis/controller is
at a stable operating temperature.
• Consult the user documentation for the counter for the recommended warm up time (at
least 45 minutes) to ensure that the counter circuitry is at a stable operating temperature.
Calibration Procedure
The calibration process includes the following steps:
1. Initial Setup—Set up the chassis or controller, install the module, and configure them in
Measurement & Automation Explorer (NI MAX).
2. Counter Verification—Verify the existing operation of the chassis or controller. This step
confirms whether the cDAQ chassis or controller is operating within the published
specifications.
Initial Setup
Refer to the quick start for your cDAQ chassis or controller for instructions on installing the
application and NI-DAQmx driver software, setting up your chassis or controller, installing
your C Series digital module, and confirming the system is operating properly.4 If you are
4For the cDAQ-9172, refer to the NI cDAQ-9172 User Guide and Specifications for installation
information.
cDAQ Chassis and Controllers Calibration Procedure | © National Instruments | 3

using the NI 9401 for verification, refer to the NI 9924 User Guide and Specifications for
installation information.
Note (cDAQ-9172) You must install the C Series digital module in slot 5 or 6 of
the chassis.
Counter Verification
CompactDAQ chassis and controllers have only one timebase to verify, so only Counter 0
needs to be checked. It is not possible to adjust this timebase, so only verification can be
performed. Complete the following steps to verify the counter on the cDAQ chassis or
controller.
1. Connect the external counter to the C Series digital module.
•(NI 9401) Connect the positive input of CHANNEL 1 to DIO 3 (pin 19) and the
negative input to COM (pin 1) using a BNC-to-leads cable, as shown in the
following figure.
Figure 1. NI 9401 and NI 9924 Signal Connections to the External Counter
SH
21
8
2
15
5
18
14
16
17
19
20
22
23
25
11
24
CHANNEL 1 CHANNEL 2
CHANNEL 3
1
3
4
6
7
9
10
12
13
COM
NC
COM
COM
NC
COM
COM
NC
COM
COM
NC
COM
COM
DIO0
NC
DIO1
DIO2
NC
DIO3
DIO4
NC
DIO5
DIO6
NC
DIO7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
•(NI 9402) Connect CHANNEL 1 to the DIO 0 BNC with a standard BNC cable, as
shown in the following figure.
4| ni.com | cDAQ Chassis and Controllers Calibration Procedure

Figure 2. NI 9402 Signal Connections to the External Counter
DIO 3
GND
DIO 2
GND
DIO 0
GND
DIO 1
GND
CHANNEL 1 CHANNEL 2
CHANNEL 3
2. Call DAQmxCreateTask to configure Counter 0 with the following parameters:
•Frequency = 5000000
•Scaled Units = Seconds
•Idle State = Low
•Initial Delay = 0
•DAQmx Timing Instance = Implicit
•Generation Mode = Continuous Pulses
•Samples to Write = 1000
3. Call DAQmxStartTask to start the generation of a square wave
4. Configure the external counter to measure frequency and use a 1 MΩ impedance.
5. Take a measurement of the square wave using the external counter.
6. Compare the counter reading to the limits in the following table.
Table 2. cDAQ Counter Limits
Set Point (MHz) Lower Limit (MHz) Upper Limit (MHz)
5 4.99975 5.00025
7. Call DAQmxStopTask to stop the generation.
8. Call DAQmxClearTask to clear the generation.
9. Disconnect the external counter from the C Series module.
The counter on the cDAQ chassis/controller is now verified.
If the cDAQ chassis or controller does not fall within the desired specifications, return it to NI
for repair. Refer to Where to Go for Support for assistance in returning the chassis or controller
to NI.
cDAQ Chassis and Controllers Calibration Procedure | © National Instruments | 5

Where to Go for Support
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.
National Instruments corporate headquarters is located at 11500 North Mopac Expressway,
Austin, Texas, 78759-3504. National Instruments also has offices located around the world to
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373718B-01 May 4, 2017