Simple Fault Finding; Error Messages; No Response To Conductivity Changes - ABB AX410 User Manual

Single and Dual Input Analyzers for Low Level Conductivity
AX410, AX411, AX413, AX416, AX418, AX450, AX455 & AX456

8 SIMPLE FAULT FINDING

8.1 Error Messages

If erroneous or unexpected results are obtained the fault may be
indicated 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
circuit or short circuit.
B: FAULTY Pt100 Temperature compensator/associated
B: FAULTY Pt1000 connections for Sensor B are either open
circuit or short circuit.
BELOW COMP RANGE If
Temp. Comp.
5.3, page 21), the indicated conductivity
value flashes if the measured conductivity
of the sample falls below the accurate
temperature compensation range.
If accurate readings are required below
this value, set
BEFORE CAT. HIGH
The pre-set conductivity value before the
cation resin column has been exceeded -
see appendix A.3 on page 75.
BEFORE CAT. LOW
The conductivity value before the cation
resin column has fallen below the
acceptable value for reliable readings
when inferred pH is selected - see
appendix A.3 on page 75.
AFTER CAT. HIGH The conductivity value after the cation
resin column has exceeded the
programmed limit - see appendix A.3 on
page 75.
Infr. pH invalid The calculated (inferred) pH is either:
outside the range 7.00 to 10.00pH if
temperature compensation (for a
dosed sample) is selected (see section
5.3, page 21)
or
outside the range 7.00 to 11.00pH if
temperature compensation (for a
dosed sample) is selected (see section
5.3, page 21)
Note. In the latter case, the calculation
becomes invalid if the after-cation
conductivity value, multiplied by 3, is
greater than the before-cation value.
Table 8.1 Error Messages
68
Possible Cause
is set to (see section
NH3
to .
Temp. Comp. UPW
NH3
NH3
NaOH
NaOH

8.2 No Response to Conductivity Changes

The majority of problems are associated with the conductivity
cell which must be cleaned as an initial check. It is also
important that all program parameters have been set correctly
and have not been altered inadvertently - see section 5, page
19.
If the above checks do not resolve the fault:
1. Check the analyzer responds to a resistance input.
Disconnect the conductivity cell cable and connect a
suitable resistance box directly to the analyzer input - see
section 7.2, page 61. Select the CONFIG. SENSORS
page and and set Temp.Comp. to None - see section 5.3,
page 21. Check the analyzer displays the correct values
as set on the resistance box - see Table 8.2 or use the
expression:
K x 10 6
R =
G
Where: R = resistance
K = cell constant
G = conductivity
Conductivity 0.05
-1
µS cm (G)
0.055 909.091kΩ
0.1 500kΩ
0.5 100kΩ
1 50kΩ
5 10kΩ
10 5kΩ
50 1kΩ
100 500Ω
500 100Ω
1000 -
5,000 -
10,000 -
Table 8.2 Conductivity Readings for Resistance Inputs
Failure to respond to the input indicates a fault with the
analyzer which must be returned to the Company for
repair. A response, but with incorrect readings, usually
indicates an electrical calibration problem. Re-calibrate the
analyzer as detailed in Section 7.3.
2. If the response in a) is correct, reconnect the conductivity
cell cable and connect the resistance box to the cell end.
Check the analyzer displays the correct values as set on
the resistance box in this configuration. If the analyzer
passes check a) but fails check b), check the cable
connections and condition. If the response for both
checks is correct, replace the conductivity cell.
8 SIMPLE FAULT FINDING
Cell Constant (K)
0.1 1.0
Resistance (R)
- -
1MΩ -
200kΩ -
100kΩ 1MΩ
20kΩ 200kΩ
10kΩ 100kΩ
2kΩ 20kΩ
1kΩ 10kΩ
200Ω 2kΩ
100Ω 1kΩ
- 200Ω
- 100Ω
IM/AX4CO Issue 11