Saab TankRadar L/2
25
US Version. Seventh edition, June 1995
Installation Manual
6
Description of the Field Communication Unit,
FCU 2160
The Field Communication Unit continuously polls data from the
Radar Tank Gauges and the Data Acquisition Units and stores it in
a buffer memory. The Field Communication Unit is the master on
the Field Bus but acts as a slave on the Group Bus.
Note:
No explosion protection is provided, so the Field Communication
Unit must be installed in a non-hazardous area.
6.1
Communication Ports
The Field Communication Unit has six communication ports, X1
to X6. The ports can be individually configured as either Group
Bus or Field Bus ports. There can be maximum four Group Buses
or four Field Buses at the same time. Maximum configuration can
be 2+4, 3+3 or 4+2 buses of each kind. However, ports X5 and X6
are never configured as Field Bus ports, while the X1 and X2 ports
are never configured as Group Bus ports.
As standard the Field Communication Unit is delivered with six
FCM interface boards for four Field Bus ports and two Group Bus
ports.
The table below shows the maximum configurations of an ex-
tended FCU:
Ports:
X1
X2
X3
X4
X5
X6
Alternative 4+2:
FB
FB
FB
FB
GB
GB
Alternative 3+3:
FB
FB
FB
GB
GB
GB
Alternative 2+4:
FB
FB
GB
GB
GB
GB
There are also two jumper connectors delivered with each unit.
These can be connected to the X5 and/or X6 for RS-232C Group
Bus communication. See figure 6.1.
Any of the FCM interface boards can be replaced with FCI inter-
face boards for RS-485 communication.
Note:
The wire terminals 1 and 3 respectively 2 and 4 on FCM board
connector are parallel connected. See installation drawing.
X1
X2
X3
X4
X5
X6
TRL/2 Bus Interface
boards, FCM boards
Jumper for
RS-232C
Figure 6.1 shows the
bus ports on the
Field Communica-
tion Unit.
