Rae QRAE PLUS PGM-2000, Руководство по эксплуатации и техническому обслуживанию

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MAINTENANCE
7-3
The following guidelines should be followed when
changing components:
1. Do not change the sensors or sampling pump, unless the
related information in Chapters 2, 4, and 8 are fully
understood and the diagnostic procedure is performed.
2. Turn off the unit and unplug the charger before changing a
battery. The battery pack screws can be tighten or loosen
with a quarter.
3. The unit continuously draws power from the battery pack,
even when off, so the battery back must be detached before
trying to change sensors or the pump.
4. When changing the sensor or the dip switch setting, detach
the battery first and then open the sensor cover only, do not
open the housing top (refer to Figure 11.)
5. The four screws that tighten the housing top are under the
unit (refer to Figure 11.) Remove the housing top only when
changing pump is necessary. Before closing the housing
top, do not forget to reconnect the tubing and the buzzer
wire. A pair of needle nose pliers is helpful to reconnect the
tubing and wire.
6. Identify the location of a specific sensor and pay attention to
the sensor pin orientation when removing and plugging in
sensors.
7. The NO and NH
3
toxic sensors require a special 300 mV
bias voltage to operate. There is a “dip switch” located on
the PCB next to the Tox 1 and 2 sensor positions. When
either an NO or NH
3
toxic sensor is plugged into a toxic
sensor socket, it is necessary to turn “OFF” the “dip switch”
for enabling the bias voltage. It is very important to set the
bias switch to the correct position when installing the toxic
sensors. The default setting of bias off (switch on) meets
the requirements of most sensors.