3.33
When an auto-cal is initiated the values of these parameters are set to zero. As auto-cal
progresses the values are updated. If auto-cal fails because a response time was exceeded
then all subsequent values will still be set at zero. The test at which it failed will have the
appropriate maximum value, as set by the user in codes 49 - 57, in it.
3.10.8 Auto Calibration Alarms
The following alarms are available in auto-calibration:
Analogue output frozen 45
Analyser in auto-calibration 46
Zero gas flow failure 63
Span gas flow failure 64
Sample gas flow failure 65 (if fitted)
Gas limits exceeded 66
All of these alarms can be allocated to relays. See Section 3.9.1 for allocation procedure.
The auto-calibration alarms 63, 64 and 66 will be cleared by either a manual zero or a manual
span calibration, irrespective of whether or not it has been successful.
3.10.8.1 Analogue Output Frozen - 45
See Section 3.10.5 for description. This alarm is cleared automatically at the conclusion of
auto-calibration.
3.10.8.2 Analyser in Auto-Calibration - 46
Goes active as soon as auto-calibration starts and is cleared automatically at the conclusion of
the sequence. May be used as an indication that the analyser is not measuring the sample
gas.
3.10.8.3 Zero Gas Flow Failure - 63
Indicates that the analyser has not detected a change in oxygen reading within a preset time
interval after switching on the zero gas.
This may be due to:
1. No zero gas or low flow.
2. Preset time intervals too short. Perform a manual calibration and measure DV lag and
90% point on a chart recorder.
The time out period for the DV lag is in Parameter 49 and for the 90% point in parameter 50.
This alarm is cleared by performing a manual calibration or by a successful auto-calibration.