HMM Series Heat Meters Installation Instructions TG201136 Issue 3, 23/07/2012 5
Installation Instructions
HMM Series
3 InStallatIon
(continued)
5
Connect M-Bus
(continued)
Meter 1
Meter n
RS232/M-Bus
Converter
(e.g. TWP3)
RS232
M-Bus
Green
Green
White
White
9 Way D
socket
9 Way D plug
6
2 RX
3 TX
5 GND
RTS7
CTS8
4 (held high)
1
RX
TX
GND
RX
TX
GND
M+
M-
TX
RX
RTS/TXEN
CTS/RXEN
RS485
RS232
The Trend RS232/M-Bus converters, TWP3, TWP20, have straight through RS232 connections as shown, but some converters
may require a RX/TX crossover connection. The Trend TWP converters may also be connected by a straight 9 Way D socket
to 9 Way D plug cable.
The meter connection is polarity independent. Use standard 2-wire telephone cable to wire the bus.
Note that the cabling for an M-Bus system requires no specified cable routing or network (e.g. star, series, etc.)
c Either IQ3/XNC with M-Bus Driver
d Or EMIC/MBA
The EMIC/MBA can connect to a maximum of between 8 and 32 meters depending on its version.
The adjacent diagram shows the physical connections. The Supervisor, IQ3 controller, EINC, and EMIC are connected to the
Ethernet bus. The EMIC is connected to its meters using the M-BUS).
The HMM meter takes the measurements and these are read by the EMIC using M-BUS protocol. The EMIC stores this data
in memory and calculates further measurements. Trend system devices can then read the measurements from the EMIC using
Trend network communications.
The EMIC is a member of the internetwork, and its firmware simulates a Lan with each meter represented as a virtual outstation
(e.g. a virtual IQ Controller). A supervisor (e.g 963) can connect to the EMIC by way of a vCNC (virtual Comunications Node
Controller) in an EINC (or 3xtend/EINC L, or IQ3).
In the above diagram, the Supervisor connects to the EINC’s Lan using a supervisor mode vCNC. The INCs, Internetwork Node
Controllers (EINC’s, EMIC’s, and IQ3’s) construct an internetwork. The supervisor can communicate across the internetwork
to obtain the meter readings from a vOS (virtual outstation). A vOS can send Sensor High and Low alarms to the supervisor
either through the EINC’s vCNC in supervisor mode if the supervisor is permanently connected or through a EINC vCNC set
to alarm mode if the supervisor is not permanently connected.
The IQ3 controller is able to send Inter-Contoller Communications to the EMIC (e.g. to obtain meter readings). The IC Comms
cannot be attribute comms so are limited to simple Data To and Data From comms.