GDS Corp GASMAX CX, Operation And Maintenance Manual

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GASMAX CX + GDS-IR Operation & Maintenance Manual, Revision 1.0
Page 19
6 MAINTENANCE
GASMAX CX
Normal maintenance for the GASMAX CX primarily involves periodic calibration on standard intervals. GDS
Corp recommends calibration at least every three months, or more often if temperature extremes,
vibration, the presence of incompatible gases or other environmental factors may accelerate the
deterioration of the sensor element. Calibration should also include inspections for clogged or wet sensor
heads, cracked or damaged enclosures and water incursion inside conduit or junction boxes.
GDS ‐ IR INFRARED SENSOR
When power is applied to the GDS ‐ IR, it enters a one ‐ minute warm ‐ up period. The output current will be
0.8 mA during the warm up time period. At the end of the warm ‐ up period with no faults present, the
GDS ‐ IR automatically enters normal operating mode and outputs 4.0 mA. If a fault is present after warm ‐
up, the detector current output will indicate a fault.
In the normal operating mode, the 4 ‐ 20 mA signal level
corresponds to the detected gas concentration. In the event
of an overrange gas release, the GDS ‐ IR will indicate an
overrange condition up to approximately 23mA. Excessive
gas will not harm the sensor and the output will return to
normal once the gas dissipates. In the event that the internal
microprocessor detects a fault condition, the output will be
set to a specific mA reading that corresponds to the type of
fault detected.
The GDS ‐ IR should be checked regularly for damage, water
ingress or hydrophobic filter clogging due to excessive dust
or dirt. If the hydrophobic filter has become contaminated
by dust, dirt or moisture, unscrew the sensor head cover,
remove the set screw and gently slide the filter down to
remove (See Fig. 7 ‐ 1). Carefully clean the filter with
compressed air and reinstall. The GDS ‐ IR can operate
without the hydrophobic filter installed if the atmosphere
contains little dust or moisture. There are no user ‐
serviceable components.
CLEANING THE GDS ‐ IR OPTICS
If necessary, the GDS ‐ IR can be partially disassembled to allow cleaning of the optical windows covering
the IR source and IR receiver. To disassemble the GDS ‐ IR, perform the following steps (See below):
1. Unscrew the outer cover in a counter ‐ clockwise direction (looking up from underneath)
2. Locate the small set screw that holds the hydrophobic filter in place. Carefully remove the screw
using a flat ‐ blade screwdriver.
3. Gently slide the hydrophobic filter down and set aside.
4. Place one Allen wrench in the hole marked “A” to hold the top section of the optical waveguide in
place. Place another through the hole marked “B” in the lower section of the optical waveguide.
Sensor Output:
0.0 mA Unit Fault
0.2 mA Reference channel fault
0.4 mA Analytical channel fault
0.8 mA Unit warm up
1.0 mA Optics fault
1.2 mA Zero drift fault
1.6 mA Calibration fault
2.0 mA Unit spanning
2.2 mA Unit zeroing
4.0 mA Zero gas level (0%LEL)
5.6 mA (10%LEL)
8.0 mA (25%LEL)
12 mA (50%LEL)
16 mA (75%LEL)
20 mA Full scale (100% LEL)
20.1- 23 mA Over-range (> 100% LEL)