MAN0585.P65
Issue 01 - 11/99
2987M5023
32
2. USING THE MINIGAS MK5
The AutoZero facility is available only during the first 60 seconds
after instrument switch on. Any attempt to AutoZero after the
60-second time limit is ignored. However, a software option
(Long Oxygen AutoZero) is available to allow the oxygen
instantaneous reading to be AutoZeroed at any time.
The limits within which the instrument can be AutoZeroed can
either be specified when ordering, or the following standard
limits are used:
Oxygen
19.9 to 21.9% VOL
Explosive
-7 to +5% LEL,
or -0.3 to +0.2% VOL
Carbon monoxide
-15 to +8ppm
Hydrogen sulphide
-7 to +4ppm
Chlorine
-1.0 to +0.5ppm
Sulphur dioxide
-2.0 to +2.0ppm
Carbon dioxide
-0.1% to +0.1% VOL
If a reading has drifted too far from its zero point, then the
Minigas Mk5 will not AutoZero that reading but will give an error
bleep (see Section 2.18). If this occurs, first ensure that the
instrument is monitoring clean, fresh air and try to AutoZero
again. If it is still not possible to AutoZero, the instrument should
be recalibrated (see Section 6).
2.9
RESETTING PEAK READINGS
The flow diagram (Figure 1) shows a Peak Reset box. If the
instrument has the peak value option configured, all four peak
gas readings can be reset at any time when in PEAK (
)
display by applying a long press to the I/O button. The peak
readings are then reset to the present instantaneous readings.
