Emerson Edition 4 Manuel D’Utilisation

Page de 166
4-3
Rosemount Tank Radar REX
Chapter 4 The Data Acquisition Unit
Installation Manual
308014EN, Edition 4
May 2013
4.3
Connecting the Data Acquisition Unit, DAU 2100
Instructions for connection of the Data Acquisition Unit is given on the 
inside of its cover.
4.3.1
Power Supply
The Data Acquisition Unit receives its power via the local line from the 
associated Radar Tank Gauge. If the distance between the Transmitter 
Head and the Data Acquisition Unit is longer than 2.0 m, a junction box 
must be used to connect an extension cable. This extension cable must 
not be longer than 50 m. For safety reasons the ends of the unused 
wires must be properly insulated and terminated. The junction box can 
either be customer supplied or supplied by Rosemount Tank Gauging as 
an option, see chapter 8. 
4.3.2
Temperature Sensors
Under the lid of the Data Acquisition Unit there are instructions printed as 
to how to connect the sensors and transducers. 
Figure 4-3.
The X21 terminal for temperature sensor connec-
tions.
Either Pt 100 (spot element) or Cu 100 (averaging sensor) temperature 
sensors can be used. If the sensors are connected with common return 
wires then jumpers must be connected in the Data Acquisition Unit 
terminals. 
Intrinsically safe connection of the temperature sensors, the RTDs, is 
made with n + 2 wires for an n-element spot or averaging sensor. There 
are spot elements with three wires for each element. The DAUs can 
connect up to 14 RTDs (Resistance Temperature Detectors) on the X21 
terminal on the motherboard. 
Connect Reference 
Resistor to terminals 
43, 44 and 45.
Connect 
temperature 
sensors.
DAU_T
empsens_Connect.eps