Det-Tronics PIR9400 PointWatch Infrared Hydrocarbon Gas Detector - Manual (Page 18)

16 95-8440 9.3
• The calibration sequence is initiated by momentarily
connecting the calibration lead to the negative
lead (common) of the power supply using the Cal
Magnet or an external switch. If the Det-Tronics
PIRTB with magnetic Cal Switch is being used, this
is accomplished by holding the Cal Magnet near the
side of the PIRTB for one second. The location of the
Cal Switch is shown in Figure
17. An alternate way of
accomplishing this is to install a pushbutton switch
between the yellow lead and the power supply
common (–), as shown in Figure
15 . Use of the Cal
Magnet to activate the Cal Switch in the PIRTB will
be referred to throughout the following procedures.
If an alternate method of initiating calibration is used,
substitute that method in all places in which the Cal
Magnet/Cal Switch activation are referenced.
• The calibration sequence can be exited at any time
during the span calibration by holding the Cal Magnet
near the Cal Switch in the PIRTB for one second.
• At all times other than when calibration is being
performed, all calibration nozzles must be capped.
This prevents dirt and water from entering the direct
path into the optics. Failure to protect the optics can
result in a fouled optics fault. If a permanent gas
delivery system is used, the delivery tube must be
plugged when not in use.
Calibration Procedure-
Inhibited Current Output During Calibration
See Table 4 for an overview of the calibration sequence.
1. Be sure that only clean air is present at the sensor.
(The microprocessor begins taking zero readings
immediately upon entering the Calibrate mode.)
If the possibility of background gases exists,
purge the sensor with clean air to ensure accurate
calibration.
2. There are two methods of applying the calibration
gas. For windy situations, a calibration wind shield
can be slipped over the sensor to capture the
calibration gas for accurate readings. Once in place,
tighten the velcro strap and connect the flexible
tubing to the nozzle. Otherwise, calibration gas
can be applied directly to the sensor through the
calibration nozzle.
3. Initiate calibration by either momentarily activating
the Calibrate pushbutton shown in Figure 15 or by
holding the Cal Magnet near the Cal Switch in the
PIRTB (if used) for one second.
– The LED will go on steady (if used)
– The current output will drop to 2.2 mA.
Description Current LED Operator action
Normal operation/no gas present 4.0 mA Off If the possibility of background gases exists, purge the
sensor with clean air to ensure accurate calibration.
Initiate calibration 2.2 mA On steady Use calibration magnet, calibrate pushbutton or manually
connect cal lead to power supply common for one second.
Zero calibration complete 2.0 mA Flashing Apply 50% LFL calibration gas.
Span calibration complete * 1.8 mA Off Shut off and remove calibration gas and cap the calibration
nozzle (or replace it with the allen head plug).
Calibration fault indication 1.6 mA Off See Troubleshooting Table 5.
* Span calibration can be aborted by using the calibration magnet, the calibrate pushbutton or manually connecting the cal lead
to power supply common for one second. The device will revert to live operation using data from the last calibration.
Table 4—Calibration Sequence, Inhibited Current Output