Endress+Hauser PROMAG 33, Operating Manual

Page: 88 / 126

Type of error Remedy ( Step 1
➔
2
➔
... )
↓ ↓
The display is pulsing or unsta-
ble, e.g. due to piston, hose or
diaphragm pumps or those
pumps with similar charac-
teristics. Carry out the following settings in the operating matrix:
1 Function DISPLAY DAMPING >10 seconds page 68
2 Function TIME CONSTANT > 5 seconds page 51
3 Function LOW FLOW CUTOFF = 0 page 72
4 Function NOISE SUPPRESSION = OFF page 72
5 Function MEASURING MODE = BIDIRECTIONAL page 75
6 Function AMPLIFIER MODE = MODE 2 page 76
If this does not produce satisfactory results, then, a pulse
damper must be installed between the pump and the
Promag.
Is there is a difference
between the internal totalizer
of Promag and the external
counter? This error occurs especially with back flows in the piping as
the pulse output cannot “subtract” such flows.
The following solutions are available:
Solution 1:
Negative flows are ignored, i.e. the display of the Promag
or external counter show identical values
→
set function
“MEASURING MODE” to “UNIDIRECTIONAL”
(see page 75).
Solution 2:
Flows in both directions are registered. This requires an
external counter or other evaluating unit to add or subtract
the appropriate pulses (forward/reverse).
Proceed as follows:
1 Fct. MEASURING MODE
→
BIDIRECTIONAL page 75
2 Fct. RELAY 2 FUNCTION
→
FLOW DIRECTION page 62
3 Connect the pulse output (Terminals 20/21 with HART;
Terminals 26/27 with RS 485) to the input of the external
counter.
4 Connect relay 2 (Terminal 24/25) to the flow direction
input of the external counter.
5 Negative flow direction
→
The external counter is to be
set so that the appropriate pulses are subtracted for
negative flow (relay 2 is then de-energised).
6 Positive flow direction
→
The external counter is to be
set so that the appropriate pulses are added with positive
flow (relay 2 is then energised).
Is a low flow indicated despite
standstill of the fluid and filled
measuring tube? 1 Check ground and potential equalisation
→
see page 28
2 Check to see if air bubbles are in the fluid.
3 Activate “LOW FLOW CUTOFF” function, i.e. enter or
increase the switch point value
→
see page 72
Is a measured value shown
despite an empty pipe? 1 Carry out an empty or full pipe adjustment and then
switch on the empty pipe detection function
→
see
page 73 ff.
2 Check the following terminal connections:
•
Electronics: EPD cable
→
see page 96 (No. 5c)
•
Remote version: EPD cable
→
see page 26
(Terminals 36 and 37)
3 Fill the measuring tube.
The current output cannot be
set to “0–20 mA”. In the function group COMMUNICATION, the function
“PROTOCOL” must be set to “OFF”
→
see page 69
continued on next page
7 Trouble-shooting, Maintenance and Repairs Promag 33
88 Hauser