GDS IR/LPI User manual

AUTHORIZED DISTRIBUTOR - GasDetectorsUSA.com - Houston, Texas USA
Quickstart Guide
GDS-IR / LPI Infrared Sensor with
Loop-powered Indicator
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IMPORTANT - Before installing the GDS-IR / LPI, make sure
there are no toxic or combustible gases are present.
Factors such as air movement, prevailing winds, convection, gas
density and emission sources should be taken into account when
determining sensor location. As with all sensors, the GDS-IR / LPI
should be protected from falling or directed water, snow, shock,
vibration and dirt.
The GDS-IR / LPI sensor may be mounted horizontally or
vertically (preferred). If horizontal, make sure the GDS-IR is
protected from dripping water. The Loop Powered Indicator LCD
can be rotated 90 degrees by opening the display cover, pulling
firmly on the display electronics, rotating the display and re-
installing (see Fig 2).
Use conduit and installation practices approved for the
appropriate area classification. When installed correctly, the GDS-
IR / LPI is suitable for use in areas rated Class 1, Div 1, Groups B,
C & D.
Unscrew the cover from the LPI junction box. Firmly grasp the
display module and pull forward. The display module should
readily pop free from the mounting posts (see Figure 2).
NOTE: It is NOT necessary to remove any screws to
disassemble the Loop Powered Indicator
Connect the +DC power wire to TB1-1. Connect the DC power
common to TB1-2. The allowable DC voltage is +18 to +30 VDC
(See Figure 3).
The GDS-IR 4-20mA output signal is available at TB1-5.
Terminals 3 and 4 should remain shorted on the field wiring side .
NOTE: The GDS-54 Loop Powered Indicator is wired to TB1 via a
‘plug-in’ two position terminal strip. The terminal strip may contain
an optional built-in bypass zener diode that allows the display
module to be removed from the circuit without interrupting the
primary 4-20mA current loop.
NOTE: The GDS-54 Loop Powered Indicator does not provide
calibration capability for the GDS-IR 4-20mA output. If calibration,
adjustment, alarm relays or MODBUS® serial interface is
required, see the GDS Corp GASMAX II / GDS-IR gas monitor. Fig 2. Loop Powered Indicator Module
INSTALLATION
POWER & 4-20mA WIRING
GDS-54 “PLUG-IN”
DISPLAY MODULE
NEMA 7 ENCLOSURE
(SIDE VIEW)
MOUNTING POST
(4 PLCS)
TERMINAL
STRIP TB1
Auto-Zero
Magnetic
Switch
GDS-IR
Infrared
Detector
Field Wiring Input
Fig 1. GDS-IR / LPI
Loop-
Powered
Indicator
Calibration Port
Note: Unit can be configured
for top conduit entry (shown) or
side conduit entry (standard).
- 832-615-3588

Fig 3. GDS-IR / LPI FIELD WIRING
Apply power to the GDS-IR / LPI and allow the
instrument to stabilize for at least one (1) hour.
IMPORTANT - Ensure there is no combustible
gas present during the auto-zero procedure.
Apply a flow of nitrogen or known ‘zero air’ if
necessary. Setting zero with background target
gas will cause erroneous readings.
Using a magnetic wand, activate the auto-zero switch
located behind the RED conduit end-cap on the Loop
Powered Display enclosure. Hold the wand in place
for at least 10 seconds, but not more than 20
seconds. The GDS-IR should momentarily output
2.2mA to indicate a successful auto-zero. The LPI
numeric display may dim or disappear momentarily.
Adjust the ZERO setting on the LPI until the display
reads “00.0”.
Apply a 0.5 to 1.0 LPM flow of 50% LEL methane
calibration gas to the GDS-IR via the 1/4” inlet
located on the bottom of the instrument. When
stabilized, adjust the SPAN setting on the LPI to read
“50.0”.
Remove the calibration gas and recheck for zero.
The instrument is now ready for operation.
INITIAL STARTUP & AUTO ZERO
During normal operation*, the output of the GDS-IR
current loop continuously indicates the concentration
of combustible hydrocarbon gas present in the
ambient atmosphere. In the event of instrument
malfunctions or calibration activities, the output
current value can be used to determine status as
shown:
OPERATION
TB1
1
2
3
4
5
6
GDS-IR
LPI
+18-32VDC
COMMON
4-20mA OUT
+
-
Red
Black
Blue
White
Auto Zero
0.0mA Instrument Fault 2.2mA Unit Zeroing
0.2mA Ref Channel Fault 4.0mA Zero Gas
0.4mA Analytic Ch Fault 5.6mA 10% LEL*
0.8mA Unit Warm-Up 8.0mA 25% LEL*
1.0mA Optics Fault 12mA 50% LEL*
1.2mA Zero Drift Fault 16mA 75% LEL*
1.6mA Calibration Fault 20mA 100% LEL*
2.0mA Unit Spanning 20 - 23mA Over-range
CLEANING
To inspect or clean the optics path, unscrew the
barrel of the GDS-IR. Remove the slotted setscrew
and hydroscopic filter. Loosen the small hex
setscrew on the center assembly and remove the
assembly by rotating the long barrel CW and the top
fitting CCW. Clean the upper and lower optics
windows using lint-free cloth. Reassemble in
reverse order.
After cleaning, always perform the auto-zero
operation as described above.
Note: The Loop Powered
Indicator will NOT operate
unless the 4-20mA current
loop output (TB1-5) is
connected to COMMON at the
receiving instrument input