Oldham MX62, Installation And Utilisation Manual

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5. Maintenance
Maintenance of gas detection systems includes inspection, servicing, calibration
and adjustment.
Inspection
and
servicing
by specialists comprise verification of key buttons,
LEDs and relay contacts, operational check of alarm thresholds with test gas to
ensure correct triggering of alarms, checking of the LCD display as well as cali-
bration and adjustment of transducers. These maintenance works should be car-
ried out half-yearly.
Calibration
of the transducers means verification of the zero point with the aid
of zero gas as well as of sensitivity and response time through test gas. Any de-
viation on the display must be followed by
adjustment
of the unit with zero and
test gas. Intervals of calibration and adjustment should always be timed to avoid
any deviation from the measuring range by more than 5 %. Even with lower de-
viations, intervals should not exceed four months.
5.1. Calibration and Adjustment
The system WinPro® provides four different methods of calibration that depend
on the transducer to be calibrated as well as the prevail-ing conditions on site.
5.1.1. Direct Calibration at the Transducer
Many transducers with a standardized output of 4-20mA (transmit-
ters) are directly adjusted, for example with the potentiometers fitted
inside the transducers. This calibration is carried out via the function
for calibration of the maintenance mode to avoid triggering of relays.
5.1.2. Remote Calibration for Standard Transducers
To adjust transducers difficult to reach from the system WinPro®
and without RS 485 connection, the 4-20mA can be aligned. This
remote calibration is done by means of the PC software ConFigPro.