FCN 4.05 015 UNSTABLE SIGNALS DURING SELF CALIBRATION [T]
General description of conditions for occurring:
The self calibration failed because at least one of the measured flow signals varied too much. A new self calibration that was done 5 minutes later did also fail because at least one of the measured flow signals varied too much.
Technical description of conditions for occurring:
The following conditions occurred twice, and there was 5 minutes between the two attempts:
The calibration of the measuring system was successful.
The zero flow signals were measured for 15s.
Variance of the flow signals were calculated.
Flow channel 1 variance SRR(34) > 146.5 OR
Flow channel 2 variance SRR(35) > 146.5
( The measuring of zero flow signals was continued for 15s.Variance of flow signals were calculated from 30s data.Flow channel 1 variance SRR(34) > 293.0 OR Flow channel 2 variance SRR(35) > 293.0 )
OR ( New zero flow signals were measured for 15s.Variance of flow signals were calculated from 15s data. Flow channel 1 variance SRR(34) > 146.5 OR Flow channel 2 variance SRR(35) > 146.5 )
OR The following conditions occurred twice, and there was 5 minutes between the two attempts:
The calibration of the measuring system was successful.
The calibration of the offset flow was successful.
Wait for 15s.
The differential flow signals were measured for 15s.
Variance of the differential flow signal was calculated.
Differential flow variance SRR(36) > 585.9.
( The measuring of differential flow signals was continued for 15s. Variance of the differential flow signal was calculated from 30s data. Differential flow variance SRR(36) > 1171.9.
OR ( New measurement of differential flow.Variance of the differential flow signal was calculated from 15s data. Differential flow variance SRR(36) > 585.9. )
The same flow went through both the flow channels while the differential flow was measured.
The unit of the variances is 0.0064*(ml/min)*(ml/min)
Note! VFC channel 2 takes care of flow channel 1!
Some possible explanations why the error has occurred:
* Air is flowing through flow channel 1.
* The ultra sonic transducer in the bubble trap 1 is broken.
* TAVA: The taration valve is leaking.
* DIVA: The direct valve is leaking.
* BYVA: The bypass valve is leaking.
* FLOW CELL: The flow cell is dirty.
* FLOW CELL: The flow cell is broken.
* FLOW OUTPUT PUMP RESTRICTOR: The restrictor is dirty.
* FLOW OUTPUT PUMP: The pump is not working properly.
* The flow system before bubble trap 1 causes an unstable level in bubble trap 1.
* FLOW OUTPUT PUMP PRESSURE TRANSDUCER: Not working properly.
* FM CPU BOARD: The signal TMO0 is not buffered according to the change order 10827.
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