13 o, 14 t – Detcon IR-642 User Manual

Page 21

adjust screw located beneath the metallic face plate. The adjustment location is marked “CONTRAST”. See f igure 7

for location.

3.13 O

PTICAL

ENSOR

EPLACEMENT

ROCEDURE

Should the optical gas sensor element (part number 370-365878-111 or 370-287724-232) require replacement, use the fol-

lowing procedure:

1 - (A) If the sensor is mounted in a classif ied area, system power to the transmitter must f irst be removed before

proceeding further.

(B) If in an unclassif ied area, remove front enclosure cover and unplug transmitter module.

2 - Remove lower half of sensor housing using an alan wrench (3 screws).

3 - Remove existing optical sensor and replace with new optical sensor (part number 370-365878-111 or 370-287724-

232).

4 - Re-install lower half of sensor housing.

5 - Restore system power (if classif ied) or plug in transmitter module and replace enclosure cover (if unclassif ied).

6 - As the unit reports “WARMING UP” message, use the magnetic programming tool and swipe across PGM1 or

PGM2. This will take the unit into a one-time gain setting mode which takes 1 minute to complete.

7 - Perform a new zero calibration followed by a new span calibration (see section 3.7).

3.14 T

ROUBLE

HOOTING

UIDE

Calibration Faults (CalFault.2)

Calibration Faults (Zero or Span) can be cleared by successfully repeating the calibration attempt. Refer to the appropriate sec-

tion in the Operator Manual and follow procedure.

Clearing Faults (Memory Error, LampFault.2, and Signal Faults.XX)

If a Fault Diagnostic occurs (Memory Error, Lamp Fault, or Signal Fault.XX) it may be a permanent problem or temporary. If

it is a temporary fault, it may be cleared using the following 1) and 2) actions. If it can not be cleared then it is a permanent

problem and advanced troubleshooting may be necessary.

1) Unplug and replug transmitters to cycle power. Determine if fault has cleared.

2) Re-initialize unit by unplugging and re-plugging transmitter and then immediately swiping your magnet over PGM1. The

unit will go into an initializing mode and reset the optical gain settings. Observe unit as the gain setting (GN) is counted down

and Ia or Ir is counted up to 2700. Record the gain set value last reported as Ia or Ir reaches 2700. Next record the final Ia and

Ir values which are displayed next. Finally record the temperature which is displayed last. Determine if fault has cleared.

Normal Readings are defined below and should be recorded to discuss with Detcon Technical Service Staff:

Gain Set:55-130

Ir:

2000-2700

Ia:

1800-2700

Temp:

32C 40C (approximately 10C higher than ambient temperature)

3) Contact Detcon for service and repair if above mentioned troubleshooting actions have not solved problem.

Zero Fault

Zero Fault is an indication that the zero level has drifted below –10% of range.

Zero Fault can be cleared by re-calibrating zero in target gas “free” air.

Non-readable display

1. If display has blue background when hot, install sunshade to reduce temperature.

2. If poor contrast, adjust contrast pot accordingly.

Nothing Displayed – Transmitter not responding

1. Verify condulet has no accumulated water or abnormal corrosion.

Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.21

This manual is related to the following products:

IR-640