Technical data

42 Electricity meters | 2CMC480022C0003
Communication adapters
Description
The Serial Communication Adapter (SCA) enables serial
data communication between the electricity meter and an
Automatic Meter Reading system (AMR).
The adapter for ABB DIN rail mounted electricity meters
The electricity meter has an infrared port for remote reading of
its measured data and identity, using the M-Bus protocol.
The SCA is an interface between the infrared port and the
external communication.
•InstallationonaDINrail
•Compactsize
•Easyinstallation
Installation
The SCA is installed on the left hand side of the meter. The
infrared port on ABB meter must face the infrared port on the
right side of the SCA. It is important that the electricity meter
and the adapter are installed side by side and that the infrared
ports are aligned.
M-Bus loop
enters
M-Bus loop
continues
1 2 3 4
1 2 3 4
M-Bus M-Bus
Connecting 2-wire M-Bus
1 2 3 4
1 2 3 4
RS232 for PC
connection
RS232 for modem
connection
GND GND
RXD TXD
DTR DTR
TXD RXD
SCA Two-wire M-Bus
The M-Bus adapter can be ordered for two-wire M-Bus
usage.
To connect the M-Bus loop, terminals 1-2 or 3-4 can be used.
The loop continues on the other two free terminals. The
M-Bus two-wire connection is polarity insensitive. The two-
wire connection is mainly used when several M-Bus slaves are
to be connected into a M-Bus loop.
The adapter is powered directly by the M-Bus and does not
require an additional power source. The M-Bus adapter
consumes 3 mA i.e. two standard M-Bus loads.
SCA RS232
The RS232 M-Bus connection is used when connecting a
M-Bus slave directly to a Master (e.g. PC/modem) without an
M-Bus interface.
The table below shows how to connect a M-Bus master com-
puter (PC). To connect to a M-Bus repeater (MODEM) switch
RXD <> TXD in table 1.
Terminal no Function 9-pole 25-pole
connector connector
1 GND -- 5 7
2 TXD <- 3 2
3 DTR >- 4 20
4 RXD -> 2 3
Connecting M-Bus Master (PC) with R232 port to the ABB adapter.