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National Instruments Corporation
3
NI cDAQ Chassis Calibration Procedure
Initial Setup
Refer to the
DAQ Getting Started
guides for instructions on installing the software, hardware, and
configuring the NI cDAQ chassis. NI cDAQ-9188 users should refer to the
NI cDAQ-9188 Ethernet
Chassis Quick Start
.
Verification
This section provides instructions for verifying the counter on an NI cDAQ chassis.
1.
Connect the counter to the C Series digital I/O module. Refer to Figure 1 for a connection diagram
of the NI 9401 and NI 9402.
a.
Connect the positive input of the counter to DIO 0 on the C Series module.
b.
Connect the negative input of the counter to COM or GND on the C Series module.
Figure 1.
NI 9401 and NI 9402 Pin Assignments
2.
Create and configure a counter output channel according to Table 2.
3.
Start the generation of a square wave.
4.
Configure the counter to measure frequency and use a 1 M
Ω
impedance.
5.
Take a measurement of the square wave.
6.
Compare the counter reading to the limits in Table 3.
Table 2.
Counter Output Configuration
Frequency
Scaled
Units
Idle
State
Initial
Delay
DAQmx Timing
Instance
Generation
Mode
Samples to
Write
5000000
Seconds
Low
0
Implicit
Continuous
Pulses
1000
Table 3.
NI cDAQ Chassis Counter Limits
Set Point (MHz)
Lower Limit (MHz)
Upper Limit (MHz)
5
4.99975
5.00025
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
DIO 3
GND
DIO 2
GND
DIO 0
NI 9402
NI 9401
GND
DIO 1
GND
