Endress+Hauser PROMAG 33 - Trouble-shooting, Maintenance and Repairs; Response of the measuring system on faults or alarm

7 Trouble-shooting, Maintenance and Repairs
7.1 Response of the measuring system on faults or alarm
The Promag 33 distinguishes between two kinds of error:
• System error (failure): instrument failure, power failure
• Process error (alarm): empty pipe, measuring range exceeded
Errors which occur during normal operation are indicated on the display
(see page 90).
The error response of the outputs is described in the following table.
Positive Zero Return not activated
Current output Pulse / Frequency output Relay outputs 1 / 2
No
System / process
error present
Measurement OK Measurement OK
Switching response
→ see page 60, 61
System or
process error
present
Failsafe mode selectable
(see page 51):
MIN. CURRENT
0–20 mA → 0mA
4–20 mA → 2mA
MAX. CURRENT
0/4–20 mA (25 mA) → 25 mA
0/4–20 mA → 22 mA
HOLD VALUE
Last valid measured value is held.
ACTUAL VALUE
Normal measured value output
despite fault.
Failsafe mode selectable
(see page 57):
FALLBACK VALUE
Signal → 0Hz
Totalizer stops operating.
LAST VALUE
Last valid measured value is held.
The totalizer operates with this
value.
ACTUAL VALUE
Normal measured value is given
despite fault, also with totalizer.
Switching response
→ see page 60, 61
Positive Zero Return activated
Current output Pulse / Frequency output Relay outputs 1 / 2
No
system and process
errors present
For 0–20 mA → 0mA
For 4–20 mA → 4mA
Signal at the fallback value:
→ no signal output (0 Hz)
Relays 1 and 2 are live,
i.e. energised
System error only
present
Process error only
present
System and
process error
present
Promag 33 7 Trouble-shooting, Maintenance and Repairs
Endress+Hauser 85