6-3
Rosemount Tank Radar REX
Chapter 6 The Field Communication
Installation Manual
308014EN, Edition 4
May 2013

6.2.2 RS 485 communication

Each FCM interface board can be replaced with FCI interface 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.

6.3 Write Inhibit/Enable Switch

There is a write inhibit switch in the FCU that can be used to prevent
unauthorized changes in the FCU database. It can be locked in the write
inhibit position by securing a locking plate with a wire through the clevis
pins.

Figure 6-3. Write inhibit/enable switch.

230 V
115 V
Reset switch
Write inhibit
Write
enable
FCU_WriteEnableInhibit.eps