Det-Tronics OPECL Infrared Hydrocarbon Gas Detector - Manual (Page 22)

20 95-8556 10.1
apERTURE KIT fOR ShORT RaNgE applICaTIONS
The Short Range Aperture Kit enables successful
application of the OPECL gas detector at distances
of approximately 5 to 30 meters. The kit is available
in Delrin plastic (included with OPECL receivers) or
optional stainless steel.
Two aperture sizes are provided:
• The 0.6" diameter (15 mm dia.) aperture is used for system
separation distances of approximately 5 to 15 meters.
• The 1.2" diameter (30 mm dia.) aperture is used for system
separation distances of approximately 15 to 30 meters.
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System separation distances greater than 30
meters should not require apertures.
procedure for System Commissioning Using the
apertures
1. Align the OPECL system using the Basic Alignment
procedure. At the completion of this alignment, the
output signal at the Receiver will indicate a fault
condition as a result of signal saturation (1.0 mA in
OPGD-Rx mode or 0.2 / 0.4 mA in PIR9400 mode).
For an EQP system, a saturation fault is indicated on
the EQP controller display and also on the S3 point
display screen.
2. Attach the aperture to the front of the OPECL
Transmitter module using the captive screws provided.
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The plastic model uses a one‑piece aperture
without holder. The stainless steel model uses a
holder with interchangeable aperture inserts.
Use the larger aperture for separation distances
from 15 to 30 meters and the smaller aperture for
distances from 5 to 15 meters. For distances around
15 meters, start with the larger aperture. An output
signal of 2.4 mA or higher indicates proper detector
operation (no fault condition). If the signal is still
saturated (1.0 mA in OPGD-Rx mode or 0.2 / 0.4 mA
in PIR9400 mode), the smaller aperture is required.
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System separation distances of 5 to 15 meters may
require the use of both apertures. Place the 0.6"
diameter aperture on the transmitter and the 1.2"
diameter aperture on the receiver if a saturated
signal exists.
3. Perform a zero calibration. After performing the zero
calibration, the Receiver module should display a normal
condition (green LED) and a steady 4 mA output.
RECOmmENDaTIONS fOR USINg ThE haRT fIElD
COmmUNICaTOR
• Ensure that the HART communicator is certified for
use in classified areas.
• The HART communication device must include
the OPECL device descriptor (DD) software menu.
The use of HART communication devices without
the proper DDs may establish generic mode HART
communication, but will not enable proper operation
with OPECL. Refer to the HART Appendix for
additional information.
• A minimum level of understanding with regard to the
operation and navigation of the HART communicator
is required. Please refer to the appropriate HART
communicator instruction manual for basic operating
instructions if required. Additional information on the
use of the HART communicator is provided within the
HART Appendix in this document.
• For proper HART communication to occur, it is
required that a 250-500 ohm resistive load be present
in the OPECL analog 4-20 mA signal loop output.
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During alignment adjustment, the HART field
communicator may occasionally display a
message stating “non‑zero status codes found.
Ignore the next 50 occurrences?” When this
occurs, enter “Yes”, and continue the Fine Alignment
procedure.
fINE alIgNmENT aDjUSTmENT USINg paRTIal
bEam blOCK TOOl
The Partial Beam Block Tool allows fine tuning of
Model OPECL alignment and should be used when
the application requires maximum signal strength and
low tolerance to potential output drift. Fine tuning the
OPECL alignment in this manner ensures that it will
operate with maximum immunity from zero drift and
false readings.
1. Perform the basic alignment procedure using the
Telescope Alignment Tool.
2. Perform a zero calibration on the OPECL receiver.
(Zero calibration should be repeated after each
alignment adjustment.)
3. Remove the brow from the front of the receiver.
4. Connect the handheld HART communicator
to the OPECL receiver module’s onboard HART
communication port.