GDS-68XP Operation & Maintenance Manual, Revision 3.4
Page 11
Type
Target Gas
Min Span
Max Span
Temp Range
Warm-Up
15
Hydrogen Sulfide
0-10 ppm
0-5000 ppm
0°C to + 50°C
2 to 4 hours
30
Mercaptan
0-15 ppm
0-30 ppm
0°C to + 40°C
4 to 8 hours
31
THT
0-15 ppm
0-30 ppm
0°C to + 40°C
12 to 24 hours
40
Odorants
0-15 ppm
0-50 ppm
0°C to + 50°C
2 to 4 hours
41
Spotleak
0-15 ppm
0-50 ppm
0°C to + 50°C
2 to 4 hours
Figure 3-1: Toxic Sensor Characteristics
SEQUENCE
Switch
Sequence
Time
Purge / Hold
Time
Total Cycle Time
(Approximate)
0
On-Demand Sequence
1 hour
1
12-15 min
40 min
1 hour
2
12-15 min
105 min
2 hours
3
12-15 min
165 min
3 hours
4
12-15 min
225 min
4 hours
5
12-15 min
285 min
5 hours
6
12-15 min
345 min
6 hours
7
12-15 min
465 min
8 hours
Figure 3-2: Sequence Timing
RECOMMENDED MINIMUM SAMPLE SEQUENCE TIMES
GAS TYPE
MINIMUM
COMMENTS
15
HYDROGEN SULFIDE, LOW RANGE (< 50 PPM)
1 HOUR
FOR MAXIMUM SENSOR LIFE, USE LONGEST
POSSIBLE SEQUENCE
15
HYDROGEN SULFIDE (> 500 PPM)
2 HOURS
FOR MAXIMUM SENSOR LIFE, USE LONGEST
POSSIBLE SEQUENCE
31
TETRAHYDROTHIOPHENE, 0-50 MG/M3
2 HOURS
TWO HOURS IS REQUIRED FOR COMPLETE
SENSOR RECOVERY FROM METHANE
30
MERCAPTAN, 0-50 MG/M3 OR 0-3 LB/MCF
4 HOURS
FOUR HOURS IS REQUIRED FOR COMPLETE
SENSOR RECOVERY FROM METHANE
40,
41
GENERAL ODORANTS, INCLUDING SPOTLEAK
2 HOURS
TWO HOURS IS REQUIRED FOR COMPLETE
SENSOR RECOVERY FROM METHANE
Figure 3-3: Recommended Minimum Sequence Times
