17
Error Codes during Automatic Calibration
. The only special error code that may
appear during automatic calibration is
"nogo"
(no go). This code, which denotes that automatic
calibration cannot proceed, may appear in the following circumstances:
i)
More than 30 seconds elapse between the
"go"
display and the introduction of
calibration gas. If this is the case, wait for an additional period up to 60 seconds,
with gas flowing through the instrument. The
"nogo"
display will be replaced by
"CAL"
when the sensors are calibrated.
ii)
A sensor is outside the normal range for automatic calibration. If this is the case,
typically after replacing a sensor, the
"nogo"
display will alternate with a display
indicative of the sensor which cannot be calibrated. Thus,
"nogo"
alternating with
"GAS 2"
indicates that the catalytic combustion sensor is outside the range for
automatic calibration. Similarly,
"nogo"
alternating with
"CO"
indicates that the
CO sensor is outside the range for automatic calibration. If this result is obtained,
the monitor must be calibrated manually.
FYI:
It is possible for a monitor to be manually calibrated and yet not calibrate with A-
CAL. This indicates a sensor sensitivity is less than a preset limit in the software
and means that the sensor should be replaced.
iii) A sensor is not sufficiently stable for calibration to proceed normally or the gas
composition is varying with time. This last condition may hold if the calibration
system has not been purged (e.g., first calibration of the day). If this is the case,
wait for an additional period of up to 60 seconds with gas flowing through the
instrument. If response is stable, the monitor will be calibrated and
"CAL"
will
appear on the display. If the instability persists, the
"nogo"
display will persist. The
instrument must then be tested manually and the cause of the malfunction corrected.
CAUTION:
Do not use a calibration gas of a different composition than Bascom-Turner's
calibration gas (Part No. MC-620 or MH-620), or pure methane or “system
gas” for automatic calibration. If some calibration gas other than those
stipulated here is to be used, calibration should be carried out manually.
