NI 9871 Operating Instructions
8
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You must connect an external power supply to the NI 9871.
This power supply provides the power for the RS485/RS422
transceivers on the module. You can use the included female
four-position pigtail to connect to an external voltage source.
Figure 1 lists the connections between an external voltage source
(of +8 V to +28 V) and the NI 9871.
Figure 1.
Four-Position External Power Connector
1
V
S
UP
2
V
S
UP
3
COM
4
COM
1
3
4
2
