Det-Tronics OPECL Infrared Hydrocarbon Gas Detector - Manual (Page 25)

23 95-8556 10.1
calibRation
CalIbRaTION OvERvIEW
Although routine calibration of the OPECL is normally
not required, the device supports non-intrusive field zero
calibration capability. Span calibration is not required.
zero Calibration
Zero Calibration is a one-step process consisting of clean
air (zero) condition adjustment only, which is performed
automatically by the device. This procedure adjusts
the "clean air" signal output only, and is normally used if
the 4 milliampere signal level has drifted. The cause of
drift is typically due to the presence of background gas
during calibration. Ensure that the optical path is clear
of hydrocarbons prior to calibration initiation to ensure
an accurate zero (clean air) condition.
ImpORTaNT CalIbRaTION NOTES
noTe
ensure that the detector has been operating for at
least two hours before calibrating.
noTe
Always ensure that the oPeCL optics are totally
free of all hydrocarbons before initiating calibration.
CalIbRaTION INITIaTION
Calibration may be initiated by any of the following
means:
• The onboard magnetic calibration switch
• Digital communication via MODBUS communication
(consult factory for details)
• Remote calibration line.
• EQP Point Display
Calibration Using magnetic Switch
The Open Path Eclipse receiver provides an onboard
magnetic calibration/reset switch for non-intrusive
calibration capability. The magnetic switch is actuated
by holding a calibration magnet at the specified location
on the device bulkhead. See Figure 2 for switch
location. An onboard tri-color LED provides status
indication during calibration.
For zero calibration, the magnetic switch must be
actuated for 2 seconds to initiate calibration (signaled
by a solid red LED). Upon initiation, the OPECL
automatically performs the zero calibration adjustment,
and then signals with a green LED when this operation
is complete.
Digital Communication Calibration
MODBUS communication may be utilized to initiate
OPECL calibration (consult factory).
DETaIlED CalIbRaTION pROCEDURE USINg
magNETIC SWITCh
zero Calibration
1. Apply magnet for 2 seconds minimum to initiate
calibration. (Hold the calibration magnet against the
side of the receiver at the location shown in Figure 2.)
A. The onboard LED turns to steady red.
B. The current output decreases to 1 mA in
OPGD-Rx mode or 2.2 mA in PIR9400 mode.
2. When zero calibration is complete:
A. The onboard LED changes from steady red to
steady green.
B. Calibration is complete and current output returns
to 4 mA.
When calibrating an EQP model, calibration status is
indicated on the EQP Point Display screen.
maintEnancE
WarnIng
Do not open cover when an explosive gas
atmosphere may be present.
noTe
Refer to the Model oPeCL Safety Manual
(number 95‑8665) for specific requirements
and recommendations applicable to the proper
installation, operation, and maintenance of all
SIL‑Certified oPeCL IR gas detectors.
ROUTINE INSpECTION
The OPECL detector should be inspected periodically to
ensure that external obstructions such as plastic bags,
mud, snow, or other materials do not block the path and
thereby impair the performance of the device.