Yokogawa Integral Oxygen Analyzer ZR202 - Manual (Page 172)

<12. Troubleshooting>
12-2
IM 11M12A01-02E 8th Edition : Jan.13,2012-00
12.1.2 Remedies When an Error Occurs
12.1.2.1 Error1: Cell Voltage Failure
Error1 occurs when the cell (sensor) voltage input to the converter falls below -50 mV
(corresponding to about 200 vol% O
2
). The following are considered to be the causes for the cell
voltage falling below -50 mV:
(1) Poor contact in terminal connections between the converter and detector
(2) Breakage in wiring cable between the converter and the detector
(3) Damage or deterioration of the sensor assembly
(4) Continuity failure between the sensor assembly electrode and the contact
(5) Wiring failure inside the detector
(6) Abnormality in electrical circuits in the converter
<Locating the failure and countermeasures>
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F12.1.2E.ai
Turn off power to the converter.
Is there any breakage
or poor contact in the wiring to the
converter terminals?
Is there any breakage
or poor contact in the wiring to the
detector terminals?
Is the sensor extremely
dirty, corroded or broken?
Is there any
disconnection or poor continuity
in the wiring between the
detector and
converter?
Is an error indicated
on the display?
End. Carry out calibration.
Replace the damaged
portions.
 Examine the wiring connection to converter terminals
"CELL+" and "CELL-" Also, check the wiring
connection in the repeater terminal box if it is used.
 Examine the wiring connection status to
detector terminals 1 and 2. Also, check that
terminals and cable conductors are not corroded.
Replace the damaged
portions.
 Remove the sensor assembly from the detector
and check for the presence of corrosion that may
cause a poor contact between the electrode and
the contact; also, check for dirt. A sensor assembly
in which no abnormality is found may be used again.
However, be sure to use a new metal O-ring and
contact even in such a case.
Replace the sensor
assembly.
See Section 11.1.2 for the
replacement procedure.
 Remove the wiring conductors from detector
terminals 1 and 2 and short out the removed
conductors. Measure the resistance of these
wiring conductors on the converter side.
The resistance value is normal if it indicates
10 Ω or less.
Replace the wiring cable.
 Turn on the power to the converter and temporarily
place the analyzer in the operating status.
Replace the sensor
assembly and temporarily
place the analyzer in the
operating status.
See Section 11.1.2 for the replacement
procedure.
The analyzer operates normally.
A failure in the detector or
the converter is suspected.
Contact Yokogawa.