Endress+Hauser Deltatop DP71B, Operating Instructions Manual

Page: 42 / 52

Troubleshooting Deltatop DP71B, DP72B, DP73B
42 Hauser
6.2 Application errors
Error Possible cause; measure
No flow indicated Installation errors
• No contact between process and transmitter
-> Check whether the valves to the differential pressure transmitter are
open.
Configuration errors
• Configuration of the transmitter or flow calculator incorrect or missing
-> Check and adjust configuration
Zero point drift;
measured value fluctuations Planning error s
• High turndown
-> If necessary use different measuring cell or multiple transmitters ("split
range", see Technical Information TI441P)
Installation errors
• Gas or liquid in the impulse pipe/transmitter
-> Vent or drain impulse pipes and transmitter (
→
ä
40)
Calibration errors
• Low flow cut-off not activated
-> Activate low flow cut-off (see Operating Instructions of Deltabar)
• No zero point adjustment
-> Perform zero point adjustment (
→
ä
40)
• No compensation for gas measurements
-> Complete temperature and pressure compensation (
→
ä
36)
Wrong measuring value Planning errors
• Wrong pipe data; wrong flow data; wrong medium data
-> Compare values of the "Sizing sheet - data sheet" to the actual values
• Inappropriate pipe (disturbed flow caused by fixtures, weld seams,
protruding sealings, inlets and outlets, fittings etc.)
-> Remove obstacles disturbing the flow profile
• Relative humidity does not match the planning data
-> Make sure that the relative humidity matches the specifications on the
calculation sheet
• Wrong measuring range of the differential pressure transmitter
-> If necessary, use different measuring cell
• Pitot tube too long or too short
-> Check whether the length of the Pitot tube is equal to
"inner pipe di wall thickness"
Installation errors
• Wrong mounting position
-> Check mounting position (
→
ä
10,
→
ä
11)
• Wrong or imprecise alignment of the Pitot tube
-> Check alignment of the Pitot tube (
→
ä
15)
• Upstream or downstream length too short
-> Check upstream and downstream lengths (
→
ä
12)
• Leakage
-> Check complete measuring system for leakage
• Welding socket projects into the interior of the pipe
-> Mount the welding socket on the outside of the pipe
Calibration error
• Compensation for gas measurements wrong or missing
-> Correct temperature and pressure compensation (
→
ä
36)
• Wrong transmitter settings
-> Check configuration of the Deltabar differential pressure transmitter
(see Operating Instructions of Deltabar)
-> Check configuration of the Flow Manager
(see Operating Instructions of RMC621/RMS621)
Maintenance errors
• Pressure tap holes of the Pitot tube blocked by dirt
--> Clean Pitot tube