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Single and dual input analyzers for pH/Redox (ORP)
AX416, AX436, AX460, AX466 & AX468
8 Simple Fault Finding
8.1 Error Messages
If erroneous or unexpected results are obtained, the fault may
be indicated in the Operating Page by an error message – see
Table 8.1. However, some faults may cause problems with
analyzer calibration or give discrepancies when compared with
independent laboratory measurements.
Error Message
A: FAULTY Pt100
Temperature compensator/associated
A: FAULTY Pt1000
connections for Sensor A are either open
A: FAULTY BALCO
circuit or short circuit.
B: FAULTY Pt100
Temperature compensator/associated
B: FAULTY Pt1000
connections for Sensor B are either open
B: FAULTY BALCO
circuit or short circuit.
Although the calibration has not failed, the
A: CAL LOW SLOPE
electrode pair associated with the sensor
B: CAL LOW SLOPE
indicated is becoming fatigued and
replacement is recommended.
The calibration of the sensor indicated has
A: PH CAL FAILED
failed. Check buffer values and repeat
B: PH CAL FAILED
buffering. If the fault persists, replace the
electrodes.
Wash Function
WASH INHIBITED
Function
A: OUT OF SAMPLE
1. The sensor indicated is not fully immersed
A: BROKEN CABLE
in sample.
(alternating display)
2.The cable associated with the sensor
B: OUT OF SAMPLE
indicated may be damaged.
B: BROKEN CABLE
(alternating display)
A: BROKEN CABLE
The cable associated with the sensor
B: BROKEN CABLE
indicated may be damaged.
1. The glass electrode associated with the
A: LOW GLASS IMP.
sensor indicated may be broken.
A: BROKEN CABLE
(alternating display)
2.The cable associated with the sensor
B: LOW GLASS IMP.
indicated may be damaged.
B: BROKEN CABLE
3.The connections associated with the
(alternating display)
sensor indicated may be faulty.
The reference electrode associated with the
A: CHECK REF.
sensor indicated may need cleaning or the
B: CHECK REF.
sensor may need replacing.
Table 8.1 Error Messages
62
Possible Cause
is set to
. Set
Off
Wash
to
– see Section 2.3.3, page 8.
On
8.2 Calibration Fail Message or No Response to
pH/Redox Changes
The majority of problems are associated with the electrodes and
cabling. Replace the electrodes as an initial check – refer to the
appropriate instruction manual. It is also important that all
program parameters have been entered correctly and have not
been altered inadvertently – see Section 7, page 56.
If the above checks do not resolve the fault:
1. Check that the analyzer responds to a millivolt input.
Connect a pH simulator, such as Model 2410, to the
transmitter input; +ve to glass and –ve to reference – see
Section 6.4, page 50 or 6.5. Select the
page and set the
Probe Type
the analyzer displays the correct values as set on the
simulator.
Note. A normal laboratory mV source is not suitable
for use as a pH simulator.
Failure to respond to the input indicates a fault with the
analyzer which must be returned to the Company for
repair. Correct response, but with incorrect readings,
usually indicates a calibration problem. Recalibrate the
analyzer as detailed in Section 7.
2. Use the pH simulator to carry out an impedance check on
the analyzer, i.e. glass to reference, glass to earth and
reference to earth – refer to simulator manual.
If the analyzer fails this test, check for moisture within the
transmitter and in particular the terminal compartment. It is
vital that all evidence of moisture is removed with the use
of a hot air drier.
3. Reconnect the electrode cable and connect the simulator
to the electrode end of the cable. Repeat the procedures
1) and 2) above. If the analyzer fails test 2), check for
moisture around the connections and check that the
insulation on the inner co-axial conductor is clean and that
the graphite layer has been removed.
8 Simple Fault Finding
CONFIG. SENSORS
to
or
. Check that
Redox
ORP
IM/AX4PH Rev. P
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