Troubleshooting Flow Charts - YOKOGAWA Dpharp vigilantplant EJA110A User Manual

9.5.2 Troubleshooting Flow Charts

The following sorts of symptoms indicate that transmitter
may not be operating properly.
Example : • There is no output signal.
• Output signal does not change even though
process variable is known to be varying.
• Output value is inconsistent with value
inferred for process variable.
Connect BRAIN TERMINAL and check self-diagnostics.
Does the self-diagnostic
indicate problem location?
NO
Is power supply
polarity correct?
YES
Are power
supply voltage and load
resistance correct?
YES
Are valves opened or
closed correctly?
YES
Is there any pressure leak?
NO
Is there
continuity through the
transmitter loop wiring?
Do the loop numbers
match?
YES
Contact Yokogawa service personnel.
YES
Refer to error message summary in
Subsection 8.5.2 to take actions.
NO
Refer to Section 6.3 to check/correct
polarity at each terminal from power
supply to the terminal box.
NO
Refer to Section 6.6 for rated voltage
and load resistance.
NO
Fully close equalizing valve, and fully
open high pressure and low pressure
valves.
YES
Fix pressure leaks, paying particular
attention to connections for impulse
piping,pressure-detector section, etc.
NO
Find/correct broken conductor or
wiring error.
F0907.EPS
Output travels beyond 0% or 100%.
Connect BRAIN TERMINAL and check self-diagnostics.
Does the self-
diagnostic indicate problem
location?
NO
Is power supply
polarity correct?
YES
Are valves opened or
closed correctly?
YES
Is there any pressure leak?
NO
Is impulse piping
to high pressure and low
pressure side correct?
YES
Is zero point
adjusted correctly?
YES
Contact Yokogawa service personnel.
9-7
9. MAINTENANCE
YES
Refer to error message summary in
Subsection 8.5.2 to take actions.
NO
Refer to Section 6.3 to check/correct
polarity at each terminal from power
supply to the terminal box.
NO
Fully close equalizing valve, and fully
open high pressure and low pressure
valves.
YES
Fix pressure leaks, paying particular
attention to connections for impulse
piping, pressure-detector section, etc.
NO
Refer to individual model user manuals
and connect piping as appropriate for
the measurement purpose.
NO
Adjust the zero point.
IM 01C21B01-01E
F0908.EPS