User manual

External Enclosures

8.0 EXTERNAL ENCLOSURES

8.1 Power Connection

Power for the OpenComms NIC-485 should be sourced from the sup-

plied wall-plug transformer. Use field-supplied wiring to connect the

outer terminals on the transformer to the screw connectors at TB3 on

the NIC-485. A field-supplied ground wire attaches to the center ter-

minal on the transformer and connects to the grounding stud in the

lower corner of the enclosure.

Figure 7 NIC485-ENCL1 internal view

8.2 Communication Connection

Communication with the OpenComm NIC-485 is generally estab-

lished by using the unit’s SiteScan interface port. The specifics on

location and wiring details can be found in the respective unit’s user

manual.

The unit’s communication port is EIA-422, which measures ~3-5VDC

between the positive and negative terminals. The connection is polar-

ity sensitive, so use a voltmeter to verify polarity. The connection is

positive-to-positive and, negative-tonegative-. The result when the

card and the unit are connected together, a voltmeter will measure ~

3-5 VDC. Once proper communication has been established, voltage

readings will fluctuate.

To SiteScan

connection

terminals on unit

Field-supplied

use 18AWG

Refer to specific unit installation

communication connection