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From other RS-485 device:
- Connect (-) to (-)
- Connect (+) to (+)
- Connect Shield (SH)
Note
EPM 2200 MULTI-FUNCTION POWER METERING SYSTEM – USER GUIDE
-
+
to Shield (SH)
SH
For All RS485 Connections:
•
Use a shielded twisted pair cable 22 AWG (0.33 mm2) or larger, grounding the shield at
one end only.
•
Establish point-to-point configurations for each device on a RS485 bus: connect '+'
terminals to '+' terminals; connect '-' terminals to '-' terminals.
•
You may connect up to 31 meters on a single bus using RS485. Before assembling the
bus, each meter must be assigned a unique address: refer to Chapter 5 of the GE
Communicator EXT User's Manual for instructions.
•
Protect cables from sources of electrical noise.
•
Avoid both "Star" and "Tee" connections (see Figure 5.7).
•
No more than two cables should be connected at any one point on an RS485 network,
whether the connections are for devices, converters, or terminal strips.
•
Include all segments when calculating the total cable length of a network. If you are
not using an RS485 repeater, the maximum length for cable connecting all devices is
4000 feet (1219.20 meters).
•
Connect shield to RS485 Master and individual devices as shown in Figure 5.6. You
may also connect the shield to earth-ground at one point.
•
Termination Resistors (RT) may be needed on both ends of longer length transmission
lines. However, since the meter has some level of termination internally, Termination
Resistors may not be needed. When they are used, the value of the Termination
Resistors is determined by the electrical parameters of the cable.
Figure 5-4 shows a representation of an RS485 Daisy Chain connection.
CHAPTER 5: COMMUNICATION INSTALLATION
Twisted Pair, Shielded Cable
FIGURE 5–3: 2-wire RS485 Connection
EPM2200 Meter
RS485 Connection
-
+
SH
5–3
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