E-Mon E34-6003200R*KIT - Manual (Page 22)

CLASS 3400 METER
62-0391-01 22
6.8.3 Connecting Class 3400 Meters to the RS-232 Key using
RS-485
On the rear panel of the RS-232 key, there are three jacks labeled as channels A, B
and C. These are RS-485 serial communications ports used to connect the meters.
Each of these channels can be connected to as many as 64 individual meters over a
total cable distance of 4,000 feet. The channels are independent and must not be
connected to each other .
*Do not use any pre-made telephone cables.
1. Plug the 4-wire RJ-11 cable/plug assembly into Channel A (or B, or C) on the
RS-232 key. Connect the other end of this cable to the meter via the RS-485
port, at the bottom right of the Class 3400 meter main power board. “DATA Link”
supplied with each RS-232 key should be utilized to connect key to meters.
Additional “DATA Link” terminal blocks can be purchased as necessary.
NOTE: The total combined cable length must not be more than 4000 feet.
2. Each meter has one yellow (TX) and one green (RX) LED located on the right
side of meter board just below the ribbon cable. If the system is properly wired,
these two LEDs will be OFF. These LEDs will flash when the computer and
meter are communicating.
Local Computer
A local computer installed in the building can communicate with the RS-485 network
utilizing E-Mon’s RS-232 conversion key. The RS-232 key is connected to the RS-485
terminals in the closest meter using a cable with an RJ-11 plug terminating the end
that is plugged into the key and is open wiring on the other end for attachment to the
meter’s 3-screw RS-485 terminal block.
Fig. 11. RS-485 Wiring.
RJ−11
PLUG
FRONT VIEW
M33196
1 - NC
2 - GND
3 - HIGH
4 - LOW
GND (GREEN)
HIGH (BLACK)
LOW (RED)
2 3 4