Emerson MONITORING OpenComms Manuel D’Utilisation

Power for the OpenComms Network card should be sourced from the 

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

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

on the Network Interface card. A field-supplied ground wire attaches 

to the center terminal on the transformer and connects to the ground-

ing stud in the lower corner of the enclosure.
Figure 9

Communications to the OpenComm Network Card 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 communications 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.