![background image](http://html1.mh-extra.com/html/national-instruments/ni-9870/ni-9870_getting-started-manual_3576038009.webp)
You must connect an external power supply to the NI 9870. This
power supply provides the power for the RS232 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 9870.
Caution
To ensure the specified EMC performance,
do not connect the power input to a DC mains supply
or to any supply requiring a connecting cable longer
than 30 m (100 ft). A DC mains supply is a local DC
electricity supply network in the infrastructure of a
certain site or building.
NI 9870 Getting Started Guide
|
© National Instruments Corporation
|
9