Rosemount TankRadar Rex DAU 2100, Service Manual

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3-19
Rosemount Tank Radar Rex
Chapter 3 Device Description
Service Manual
308012En, Ed.2
May 2013
3.2.1 Field Bus and Group Bus Communication
The Field Communication Unit has six communication ports, X1 to X6.
The standard configuration is six
TCM interface boards
with four
TRL/2 Field Bus (FB) ports and two TRL/2 Group Bus (GB) ports. As an
alternative, the FCM boards at the Group and Field Bus ports can be
replaced with
FCI boards
for RS-485 communication. The FCU
communication ports can be configured according to the following table:
The Field Communication Unit has six communication ports for the Field
bus and Group bus communication. The Group Bus ports can be used
independently of each other. For example, one Group Bus can be
connected to a PC with OPI software, and at the same time another
Group Bus may be connected to a plant host computer.
There are four Field Bus ports each of which can connect up to eight
units. A unit may consist of a Rex gauge, or a Rex gauge connected to a
DAU.
If the number of cables to a Field Communication Unit is higher than the
capacity of the connectors then standard Junction Boxes (fitted for use in
the environment in question) can be used to split the connections.
There is a steel plate to shield the bus ports from the rest of the
electronics in the FCU.
3.2.2 Input and Database Registers
The input register is a dynamic register which holds the values that the
FCU receives over the TRL/2 bus from connected slave units (RTGs,
DAUs). Level, temperature and other measured data is stored in the
input register, and are sent to the master on request.
The database contains information on program version, communication
protocol values, slave configuration, memory configuration etc. It is
divided into one write protected and one unprotected part. See Chapter
4.1.7 on how to remove the write protection.
X1 X2 X3 X4 X5 X6
FB FB FB FB GB GB
FB FB FB GB GB GB
FB FB GB GB GB GB