Det-Tronics PIR9400 PointWatch Infrared Hydrocarbon Gas Detector User Manual

Page 20

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

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

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

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

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

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

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