Response Of Outputs To Errors - Endress+Hauser CNGmass DCI Operating Instructions Manual

Troubleshooting
!
Failsafe mode of outputs and totalizers
Process/system error is present
"
Caution!
System or process errors defined as "Notice messages" have no effect whatsoever on the inputs and outputs.
See also the information on → ä 29.
MODBUS RS485 In the event of faults, the value "NaN" (not a number) is transmitted instead of the current
measured value.
Current output MIN. CURRENT
The current output will be set to the lower value of the signal on alarm level depending on
the setting selected in the CURRENT SPAN (È "Description of Device Parameters"
manual).
MAX. CURRENT
The current output will be set to the upper value of the signal on alarm level depending on
the setting selected in the CURRENT SPAN (È "Description of Device Parameters"
manual).
HOLD VALUE
Measured value display on the basis of the last saved value preceding occurrence of the
fault.
ACTUAL VALUE
Measured value display on the basis of the current flow measurement. The fault is ignored.
Pulse output FALLBACK VALUE
Signal output → no pulses
HOLD VALUE
Last valid value (preceding occurrence of the fault) is output.
ACTUAL VALUE
Fault is ignored, i.e. normal measured value output on the basis of ongoing flow
measurement.
Frequency output FALLBACK VALUE
Signal output → 0 Hz
FAILSAFE VALUE
Output of the frequency specified in the FAILSAFE VALUE function.
HOLD VALUE
Last valid value (preceding occurrence of the fault) is output.
ACTUAL VALUE
Fault is ignored, i.e. normal measured value output on the basis of ongoing flow
measurement.
Totalizer STOP
The totalizers are paused until the fault is rectified.
ACTUAL VALUE
The fault is ignored. The totalizer continues to count in accordance with the current flow
value.
HOLD VALUE
The totalizers continue to count the flow in accordance with the last valid flow value
(before the error occurred).
76
10.5

Response of outputs to errors

Note!
The failsafe mode of totalizers, current, pulse and frequency outputs can be customized by means
of various functions in the function matrix.
Detailed information È "Description of Device Parameters" manual.
You can use positive zero return to set the signals of the current, pulse and status outputs to their
fallback value, for example when measuring has to be interrupted while a pipe is being cleaned. This
function takes priority over all other device functions. Simulations, for example, are suppressed.
CNGmass DCI MODBUS RS485
Positive zero return is activated
–
Output signal corresponds to "zero flow"
Output signal corresponds to "zero flow"
Output signal corresponds to "zero flow"
Totalizer stops
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