SA_001_2019-07_10.00 Transmitter PASCAL Ci4
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2.4 Troubleshooting
In the event of a critical device malfunction, an alarm current of < 3.6 mA or > 21 mA is
permanently issued at the output.
The alarm current can be deactivated by a manual restart only.
3
Requirements for the Operator
The operator has to consider the following requirements to ensure that the safe function is
not jeopardised.
3.1 Unsafe Operating Conditions
Avoid the following functions while using the devices as part of a protection system:
HART multi-drop operation in fixed current mode
Pressure or current simulation
Adjustment of the current output
Communicating with the device via HART or the display module does not affect the safe
function, providing no parameters are changed that affect the current signal.
The value at the current output is no longer proportional to the pressure when using the
table function, for example, to map the tank shape when measuring the level. A fault in the
support points of the table leads to a faulty signal current. There is a linear interpolation of
the measurement between these support points. This reduces the accuracy between the
support points.
When using the table function in SIL application, the operator should therefore take appro-
priate measures to ensure the correctness and sufficient accuracy of the table.
3.1.1
Ci4 LEVEL
For devices with operating software for level applications please pay attention to the fol-
lowing points:
Set the height offset first and t
hen scale the current output (parameters „value for 4 mA“
and „value for 20 mA“). This is because the scaling of the current output is based on the
height offset.
Ensure that the hydrostatic pressure of a completely filled tank does not exceed the nomi-
nal range of the device.
Ensure that the value for 4 mA does not represent a level that lies below the process con-
nection of the device.
