Det-Tronics PIR9400 PointWatch Infrared Hydrocarbon Gas Detector - Manual (Page 17)

15 95-8440 9.3
CALIBRATION
The PointWatch Detector is factory calibrated for
methane and, unlike catalytic detectors, does not
require routine calibration to ensure proper operation.
Guidelines for when calibration or bump tests should
be performed/ checked are listed in Table
3 .
NOTE
To check calibration, inhibit output loads as
necessary, then apply
50% LFL calibration gas to
the detector using the equipment provided in the
calibration kit. Ensure that the correct calibration
gas is used. Check the current output for the
appropriate response (
12 mA).
NOTE
Drift will be indicated by a constant zero offset in
one direction either above or below
4 mA. The
presence of background gas would be indicated
by a small but constantly changing output.
CaLIBRaTION EqUIPMENT
The following equipment is required to calibrate the
PointWatch Detector (calibration kits from Det-Tronics
contain all items below):
– 50% LFL calibration gas
– Calibration nozzle (for aluminum model)
– Regulator (minimum 2.5 liter/minute flow rate)
– Three feet of tubing.
CaLIBRaTION PROCEDURES
The procedures in this section explain calibration
sequences for both stand alone PointWatch Detector
applications (when a user supplied or no termination box
is used) and for applications where the detector is used
with the Det-Tronics supplied termination box (containing
a magnetic reed switch and LED). For applications where
the PointWatch Detector is used with the Infiniti U
9500
Transmitter or the Eagle System, refer to those instruction
manuals for the calibration procedure.
When the Model PIR 9400 Detector is used in a
stand-alone configuration or with transmitters and
controllers other than those supplied by Det-Tronics, the
current loop output must be monitored in order to calibrate
(for both inhibited and live current loop configurations).
When the detector is used with a Det-Tronics termination
box, the magnetic switch and LED in the termination
box are used to initiate and annunciate the calibration
sequence. The current loop output also indicates the
calibration sequence (for both inhibited and live current
loop configurations).
iMPoRtant CaLiBRation notES
• Ensure that the detector has been operating for at
least two hours before calibrating.
• Do not open the explosion-proof enclosure when
power is applied to the system unless the appropriate
permits have been procured.
• The calibration gas used must be the same as the gas
selected on the Gas Selection Switch. The factory
setting is for methane, so use methane to calibrate
if the Gas Selection Switch is set in position “
0 .” If
the Gas Selection Switch is set in any other position,
ensure that the correct gas is used to calibrate. See
Figure
14 . Only 50% LFL calibration gas can be
used to calibrate the PointWatch Detector.
• If the detector is being used in a stand alone
configuration, the use of an inhibited current loop
is recommended. Live current loop calibration was
designed primarily for use with the Infiniti U
9500
Transmitter or the EQP system. Accomplishing live
current loop calibration manually is possible but
not recommended. Instructions for live current
loop calibration are provided after the “Calibration
Procedure - Inhibited Current Output During
Calibration” procedure.
Table 3—Calibrate or Check
Function Calibrate Check
Startup X
Gas selection switch changed X
Non-standard gas X
(using linearization other than methane)
Replace any part X
Constant zero offset X
Periodic Functional Testing X
(at least once a year)