Endress+Hauser Proline Prowirl 72, Operating Instructions Manual

Page: 52 / 114

9 Trouble-shooting Proline Prowirl 72
52 E Hauser
9.4 Response of outputs to errors
!
Note!
The failsafe mode of totalizers and current, pulse and frequency outputs can be configured by means
of various functions in the function matrix.
Positive zero return and error response:
You can use positive zero return to set the signals of the current, pulse and frequency outputs to
their fallback value, for example when operation has to be interrupted while a pipe is being cleaned.
This function has priority over all other device functions; simulations are suppressed, for example.
Response of outputs and totalizers to errors
Process/system error present Positive zero return activated
"
Caution!
System or process errors defined as “notice messages” have no effect whatsoever on the inputs and outputs. Please refer
also to the information on Page 30 ff.
Current
output MIN. CURRENT
Depends on the setting selected in the CURRENT RANGE
function. If the current range is:
4...20 mA HART NAMUR
→
output current = 3.6 mA
4...20 mA HART US
→
output current = 3.75 mA
MAX. CURRENT
22.6 mA
HOLD VALUE
Measured value output is based on the last measured value
saved before the error occurred.
ACTUAL VALUE
Measured value output is based on the current flow
measurement. The fault is ignored.
Output signal corresponds to zero flow
Pulse output FALLBACK VALUE
Signal output
→
output 0 pulse
HOLD VALUE
Measured value output is based on the last valid flow data
before the error occurred.
ACTUAL VALUE
Measured value output is based on the current flow
measurement. The fault is ignored.
Output signal corresponds to zero flow
Status output In the event of a fault or power supply failure:
Status output
→
not conductive
No effect on the status output
Totalizer STOP
The totalizer stops at the last value before the alarm condition
occurred.
HOLD VALUE
The totalizer continues to count the flow on the basis of the
last valid flow data (before the fault occurred).
ACTUAL VALUE
The totalizer continues to count the flow on the basis of the
current flow data. The fault is ignored.
Totalizer stops