Modbus Rtu Wiring - Honeywell 3400 Installation Instructions Manual

E-MON CLASS 3400 METER

6.10 Modbus RTU Wiring

The E-Mon Class 3400 Modbus meter communicates with building automation
equipment over a 2-wire (3-conductor) RS-485 network using Modbus RTU
protocol. The meters are networked in a daisy-chain configuration (Section 6.7)
with BELDEN 1120A cable or equivalent. The cable rating of 600V allows the RS-
485 network to be connected to 480-volt meters. Up to 52 meters can be installed
on a network string. The maximum combined length of all daisy-chained cables
must not exceed 4000 feet.
The meter-to-network connection is through the 3-screw terminal which is
located on the Main Power Board of the meter.
RS-485
TERMINAL
The meter is shipped with a Modbus ID number of 01. This must be changed if the
network has more than one meter installed. The change must be done before the
meter is introduced into the network. The meter can be numbered from 1 to 247.
There can be no duplicate numbers on a network, so caution must be taken when
assigning a meter ID number prior to its installation on the RS-485 network.
SEE SECTIONS 10 AND 11 FOR INSTRUCTIONS ON CHANGING I.D. AND IP
ADDRESSES.
62-0398—02
Fig. 15. Modbus RTU Wiring.
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