ABB AX410 User Manual

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ABB AX410 User Manual Manual pdf 70 page image

Single and Dual Input Analyzers for Low Level ConductivityAX410, AX411, AX413, AX416, AX418, AX450, AX455 & AX456 8 SIMPLE FAULT FINDING68 IM/AX4CO Issue 118 SIMPLE FAULT FINDING8.1 Error MessagesIf erroneous or unexpected results are obtained the fault may beindicated by an error message - see Table 8.1. However, somefaults may cause problems with analyzer calibration or givediscrepancies when compared with independent laboratorymeasurements.8.2 No Response to Conductivity ChangesThe majority of problems are associated with the conductivitycell which must be cleaned as an initial check. It is alsoimportant that all program parameters have been set correctlyand have not been altered inadvertently - see section 5, page19.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 asuitable resistance box directly to the analyzer input - seesection 7.2, page 61. Select the CONFIG. SENSORSpage and and set Temp.Comp. to None - see section 5.3,page 21. Check the analyzer displays the correct valuesas set on the resistance box - see Table 8.2 or use theexpression:R =Where: R = resistanceK = cell constantG = conductivityFailure to respond to the input indicates a fault with theanalyzer which must be returned to the Company forrepair. A response, but with incorrect readings, usuallyindicates an electrical calibration problem. Re-calibrate theanalyzer as detailed in Section 7.3.2. If the response in a) is correct, reconnect the conductivitycell cable and connect the resistance box to the cell end.Check the analyzer displays the correct values as set onthe resistance box in this configuration. If the analyzerpasses check a) but fails check b), check the cableconnections and condition. If the response for bothchecks is correct, replace the conductivity cell.Error Message Possible CauseA: FAULTY Pt100A: FAULTY Pt1000Temperature compensator/associatedconnections for Sensor A are either opencircuit or short circuit.B: FAULTY Pt100B: FAULTY Pt1000Temperature compensator/associatedconnections for Sensor B are either opencircuit or short circuit.BELOW COMP RANGE If Temp. Comp. is set to NH3 (see section5.3, page 21), the indicated conductivityvalue flashes if the measured conductivityof the sample falls below the accuratetemperature compensation range.If accurate readings are required belowthis value, set Temp. Comp. to UPW.BEFORE CAT. HIGH The pre-set conductivity value before thecation resin column has been exceeded -see appendix A.3 on page 75.BEFORE CAT. LOW The conductivity value before the cationresin column has fallen below theacceptable value for reliable readingswhen inferred pH is selected - seeappendix A.3 on page 75.AFTER CAT. HIGH The conductivity value after the cationresin column has exceeded theprogrammed limit - see appendix A.3 onpage 75.Infr. pH invalid The calculated (inferred) pH is either:outside the range 7.00 to 10.00pH if NH3temperature compensation (for a NH3dosed sample) is selected (see section5.3, page 21)oroutside the range 7.00 to 11.00pH if NaOHtemperature compensation (for a NaOHdosed sample) is selected (see section5.3, page 21)Note. In the latter case, the calculationbecomes invalid if the after-cationconductivity value, multiplied by 3, isgreater than the before-cation value.Table 8.1 Error MessagesCell Constant (K)ConductivityμS cm -1 (G)0.05 0.1 1.0Resistance (R)0.055 909.091kΩ - -0.1 500kΩ 1MΩ -0.5 100kΩ 200kΩ -1 50kΩ 100kΩ 1MΩ5 10kΩ 20kΩ 200kΩ10 5kΩ 10kΩ 100kΩ50 1kΩ 2kΩ 20kΩ100 500Ω 1kΩ 10kΩ500 100Ω 200Ω 2kΩ1000 - 100Ω 1kΩ5,000 - - 200Ω10,000 - - 100ΩTable 8.2 Conductivity Readings for Resistance InputsK x 106G