Troubleshooting Flowcharts - YOKOGAWA DPharp EJXC80A User Manual

6.7.2 Troubleshooting Flowcharts
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 communicator and check self-diagnostics.
Does the self-diagnostic
indicate problem location?
NO
Refer to error message summary in
Subsection 6.7.3 or in each
communication manual to take actions.
Is power supply
polarity correct?
YES Check/correct polarity at each terminal
from power supply to the terminal box.
Are power
supply voltage and load
resistance correct?
Check rated voltage and load
YES
resistance.
Are valves opened or
closed correctly?
Fully close equalizing valve, and fully
YES
open high pressure and low pressure
valves.
Is there any pressure leak?
NO
Fix pressure leaks, paying particular
attention to connections for impulse
piping,pressure-detector section, etc.
Is there
continuity through the
transmitter loop wiring?
Do the loop numbers
match?
Find/correct broken conductor or
YES
wiring error.
Contact Yokogawa service personnel.
YES
NO
NO
NO
YES
NO
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<6. Maintenance>
Output travels beyond 0% or 100%.
Connect BRAIN TERMINAL and check self-diagnostics.
Does the self-
diagnostic indicate problem
location?
NO Refer to error message summary in each
communication manual to take actions.
Is power supply
polarity correct?
YES
Check/correct polarity at each terminal
from power supply to the terminal box.
Are valves opened or
closed correctly?
Fully open the low pressure valve.
YES
Is there any pressure leak?
NO
Fix pressure leaks, paying particular
attention to connections for impulse
piping, pressure-detector section, etc.
Is zero point
adjusted correctly?
YES
Adjust the zero point.
Contact Yokogawa service personnel.
6-7
YES
NO
NO
YES
NO
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