GE Grid Solutions Multilin 9450 - 5.7 Linking Multiple EPM Meters in Series; 5.8 Remote Communication Overview

CHAPTER 5: COMMUNICATION WIRING LINKING MULTIPLE EPM METERS IN SERIES
EPM 9450/9650 ADVANCED POWER QUALITY METERING SYSTEM – INSTRUCTION MANUAL 5–11
As the table above shows, all I/O modules are shipped pre-programmed with a baud rate
of 57600 and addresses. For programming instructions, refer to the GE Communicator
Instruction Manual.
See the next page for the external displays’ VA Ratings.
If you are using a PSIO (for 125V AC/DC input) your maximum VA is 12.
5.7 Linking Multiple EPM Meters in Series
You may connect a total of 31 EPM meters in series on a single bus using RS485. The cable
length may not exceed 4000 feet (1219 meters). Before assembling the bus, each EPM
meter must be assigned a unique address. See the GE Communicator Instruction Manual
for instructions.
• Connect the + and - terminals of each EPM meter. Use jumpers on any RS485
Master connected at the end of the chain.
• Connect the shield to the (S) terminal on each EPM meter and to the Ground on the
RS485 Master. This connection is used to reference the EPM meter’s port to the
same potential as the source. It is not an earth-ground connection. You must also
connect the shield to earth-ground at one point.
• Provide termination resistors at each end, connected to the (+) and (-) lines. RT is
approximately 120 Ohms, but this value may vary based on length of cable run,
gauge or the impedance of the wire. See RT EXPLANATION in Section 5.3 .
Figure 5-9: Linking Multiple EPM Meters in Series
You can use an RS485 repeater to network several links of instruments.
NOTE
Note
• A maximum number of 31 EPM meters may be connected to one repeater.
• A maximum number of 31 repeaters may be included on the same network.
5.8 Remote Communication Overview
EPM Display VA Ratings
P40N
PLUS
LED Display 3.8VA
P60N LCD Display 5VA
Twisted pair, shielded (SH) cable
R
T
+ - SH
R
T
+ - SH
+ - SH
+ - SH
Slave device 1
Slave device 2
Last Slave device N Master device
Earth Connection, preferably at
single location
Twisted pair, shielded (SH) cable Twisted pair, shielded (SH) cable