Det-Tronics PIR9400 PointWatch Infrared Hydrocarbon Gas Detector - Manual (Page 20)

18 95-8440 9.3
8. After successful calibration, close the valve on the
calibration gas canister, remove the flexible tube
from the calibration nozzle and replace the nozzle
cap. If the calibration wind shield was used, remove
it from the PointWatch Detector. The detector will
return to normal operation after the gas level has
returned below
5% LFL.
iMPoRtant
The calibration ports must be capped to prevent
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 - Live Current Output During
Calibration
Sequence Summary: During calibration with a live current
loop output, the current output drops to
2.2 mA during
the zero calibration then rises to reflect the actual gas
level for the span calibration. At the end of calibration,
the current level locks to indicate that the calibration is
complete. These current levels and their significance are
summarized as follows:
4.0 mA Zero gas level (0% LFL), initial state - normal
operation, no gas present
2.2 mA Zero calibration in progress
12.0 mA Span calibration lock-in
1.6 mA Calibration fault - reset unit.
iMPoRtant
LiVE CuRREnt outPut CaLiBRation notES
• If the PIR 9400 is being used in a stand alone
configuration, the use of an inactive 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 difficult because
precision timing is required.
• Inhibit alarm outputs before performing this
calibration procedure. Alarm levels will be exceeded
using the live current output calibration procedure.
• All calibration notes listed at the beginning of the
“Calibration Procedures” section also apply to this
procedure. Review those notes prior to proceeding.
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. 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 and the current output
will drop to 2.2 mA. After the zero is stable (typically
1 minute), the LED will start to flash and the current
level changes to 2.0 mA. When the LED goes
off for the first flash, immediately reactivate the
calibration switch for one second only. This places
the current loop output in the live mode.
– The current level rises to 4.0 mA and the LED
begins flashing.
If unsuccessful at entering live calibration mode,
abort calibration by momentarily reactivating
the magnetic calibration switch or pressing the
calibrate pushbutton. Repeat steps 1 - 3.
Proceed to step 4 .
If calibration mode was inadvertently exited:
– The LED will turn off
– The current output will remain at 4.0 mA (normal
operation).
This occurs when the Cal switch is activated for too
long when the LED begins flashing. Repeat all of
step 3 and proceed.
If zero calibration fails:
– The LED will turn off
– The current output will drop to 1.6 mA.
Reset the detector by cycling power to the detector
or by holding the Cal Magnet near the Cal Switch
in the PIRTB (if used) for one second. Begin
calibration again at step 1 .