OPERATING MODES
The OPECL has four operating modes: warm-up,
normal, alignment and calibrate.
Warm-up
Warm-up mode is entered upon application of 24 Vdc
operating power. During warm-up, the 4-20 mA current
loop output will indicate warm-up, the indicating LED is
amber, and the alarm outputs are disabled. The warm-
up mode lasts nominally two minutes after power-up.
Normal
After warm-up mode is completed, the device
automatically enters the Normal mode, and all analog
and alarm outputs are enabled.
Alignment
The OPECL modules must be properly aligned before
normal operation is attained. There are two alignment
procedures:
1. Basic Alignment requires the OPECL Alignment Kit.
2. Fine Alignment requires the OPECL Alignment Kit
and a handheld HART Communicator.
Calibrate
After alignment is completed, zero calibration is
required. Span calibration of the OPECL is normally not
required; however, the user has the option to verify
proper calibration or to perform calibration procedures if
necessary. Refer to the "Calibration" section in this
manual for details.
4 TO 20 MA CURRENT LOOP OUTPUT
OPECL provides a linear current loop output that is
proportional to the detected gas level. Fault and
calibration status are also indicated by this output.
The factory default for full-scale 5 LFL-meters output is
20 mA. MODBUS interfaces also have the ability to
calibrate the 4 mA and 20 mA levels.
FAULT INDICATION
Faults and status conditions are indicated using the 4-
20 mA analog signal output. Refer to Table 3.
Signaling modes include two predefined and one user
defined mode. PIR9400 mode (default) provides
compatibility with the DEC R8471J Gas Controller.
OPGD-Rx mode is available as well as a user defined
mode for third party compatibility.
5
95-8556
2.1
Default
Configurable Options
Gas Type
Methane
Methane, Ethane,
Propane, Butane,
Propylene, Special
Measurement Range
0-5
0-2, 0-5
(LFL-M)
Low Alarm Threshold
1
0.25 to 3
(LFL-M)
High Alarm Threshold
2
1 to 3
(LFL-M)
Beam Block Delay
60 Seconds
3600 Seconds
Fault Mode
PIR9400
OPGD-Rx, User Defined
Table 2—Factory Default Settings
Status 4-20
mA
Level (±0.1)
PIR9400
OPGD-Rx
Normal Gas: –0.5 to 5 LFL-M
2.4 to 20.0
20.0
Warmup - Standard range model
1.0
1.0
Warmup - Long range model
1.0
1.0
Zero Calibration
2.2
1.0
Calibration Fault
1.6
1.0
Beam Block
1.0
2.0
Back-up Lamp Active*
2.4
3.0
Calibrate Active at Startup
0.6
1.0
EE Error
1.2
1.0
Ref. ADC Saturated
0.2
1.0
Active ADC Saturated
0.4
1.0
24 VDC Fault
0.8
1.0
Zero Drift
2.4
1.0
Flash CRC Error
1.2
1.0
RAM Error
1.2
1.0
Over Range
20.4
20.4
Table 3—Detector Status Conditions Indicated by Current Level
*Device is still functional. Gas overrides this indication.
