GE Industrial Solutions EPM1500 Single Point Submetering System - Manual (Page 34)

4–2 EPM 1500 SUB-METER– INSTRUCTION MANUAL
CHAPTER 4: COMMUNICATIONS
Note The EPM 1500 optical port is disabled for units with 2-wire RS485 connections.
4.1.2 RS232 Wiring for Modbus
The wiring for Modbus communications for RS232 is indicated below.
4.1.3 Modbus Commands
The EPM 1500 is capable of acting as a remote slave unit to a Modbus master device via
modem, RS232, RS485, or PLC. Up to 32 EPM 1500 meters (or other RS485 devices) can be
daisy-chained together on a single LAN.
The EPM 1500 communicates at a default baud rate of 19200, with no parity and 1 stop bit.
The default Modbus address is 100. Changes to the default baud rate or address can be
accomplished through the configuration file upload.
The following Modbus commands are supported by the EPM 1500:
• 03: Read R4 type register(s)
• 06: Write single register; address “0” is used as the broadcast address
• 16: Write multiple registers; address “0” is used as the broadcast address
4.1.4 Fixed Modbus Values
The EPM 1500 provides fixed register values indicating the meter's serial number, the
meter's version number, and the Modbus addresses.
4.1.5 Modbus Data Register (R4 Type) Groups
The EPM 1500 has divided the supported register map (see following pages) into the
following register groups for various fixed and dynamic data values:
• Setup Information
• Interval
• Average Interval Data
• Instantaneous Data
• Three-Phase Data
• Real Time Data
• Meter Configuration Data
The EPM 1500 provides access to stored-interval data channels via Modbus command. The
data items as defined in the following register map are based on default data channels
that include the following 3-phase-totaled values (interval average) per meter:
Color Function DB-9 Pinout
Black TX 2
Red RX 3
Green GND 5