SATEC EM920 Operation Manual - Manual (Page 27)

Chapter 2 Operating the EM920
Communicating with the EM920
EM920 Power Quality and Revenue Meter 27
trigger the Data recorder for fast profiling of RMS voltages
and currents during a fault.
See Configuring the Fault Recorder in Chapter 5 for more
information on operation of the Fault recorder.
Communicating with the EM920
Communication with the EM920 is provided either via the
embedded optical IR and RS-485 ports, or via the expansion
communication ports. See the EM920 Installation Manual for
a full list of available communication options and connection
diagrams.
Optical Port
The EM920 has an ANSI-compatible optical infrared port for
local meter reading via a hand-held unit or a portable PC.
The IR port is identified in the EM920 as port COM1. It is
factory preset to 19200 bps, 8-bits/No-parity data format,
and the Modbus RTU protocol.
You can change the default baud rate or protocol for the IR
port from the front display or via PAS (see
Setting Up Serial
Communication Ports in Chapter 5).
Serial Communications
The EM920 has an embedded RS-485 serial port, and the
second configurable RS-232/RS-485 port can be provided
with an expansion Ethernet module. See the EM920
Installation Manual for the serial port connections.
The embedded RS-485 port is identified in the meter as port
COM3, and the expansion RS-232/RS-485 serial port is
identified as port COM4.
The expansion port is provided with two green RX and TX
LEDs that blink when the port receives or transmits data.
You can check the present serial port settings via the Device
Info display (see
Device Info Display in Chapter 3).
Both serial ports are factory preset to 19200 bps, 8-bits/No-
parity data format, and the Modbus RTU protocol. See
Setting
Up Serial Communication Ports on how to change the factory-
set options for your serial ports.
Ethernet Connection
An expansion 10/100Base-T Ethernet module provides a
direct connection to the Ethernet.
The port has two indication LEDs that operate as follows:
LED Color Status Description
LINK Green Lights The good link is detected (slightly blinks
when the port receives or transmits data)
ACT Yellow Blinks Activity on the port - the port receives or
transmits data