Detcon 1000_H2S - Manual (Page 21)

Model 1000 H2S Echem
Model 1000 H2S Echem Instruction Manual Rev. 2.8 Page 17 of 30
Material Requirements
 Detcon Part Number 327-000000-000 MicroSafe™ Programming Magnet.
 Detcon Part Number 942-001123-000 Zero Air cal gas. (Ambient air can be used, if it can be verified that
no target gas is present).
 Span gas cylinder containing H
2
S gas in background N2 (nitrogen) as per the following range table. If
available, span gas cylinders in background Methane (natural gas) or air can also be used.
6.1.1 Zero Calibration
Zero Calibration should be performed quarterly in the field. The AutoZero function is used to zero the sensor.
The dilution airflow (with sample turned off) can be used to zero calibrate the sensor. Alternately, a zero air or
N
2
cylinder connected to the calibration port can be used.
1) Turn the sample flow mass control off, leaving only the airflow to provide the zero gas. Allow the unit 5
minutes to stabilize.
2) Enter the calibration menu by holding the programming magnet stationary over “PGM 1” (see above) for 3
seconds until the display reads “1-ZERO 2-SPAN”, and remove the magnet. Note that the “CAL” LED
comes on.
3) Enter the zero menu by holding the magnet stationary over “PGM 1” for 3 seconds until the display reads:
“AUTOZERO”, and remove the magnet. The sensor will enter the auto zero mode. When complete the
sensor will display “ZERO COMPLETE” for 5 seconds and then return to the normal operation menu,
“0.00PPM H2S”.
4) Re-open the sample flow mass control and re-establish the target sample flow rate per the arrow indicator
on the H
2
S sample rotameter.
6.1.2 Span Calibration
Table 3 Sample Flow Rate
DM-624 Range
(ppm)
Sample Flow
(cc/min)
Air Flow
(cc/min)
Span Gas Flow
(cc/min)
H
2
S Cal Gas
(ppm)
0-10 200 Labeled “S
”
500 250 Labeled “C
”
10
0-20 200 Labeled “S
”
500 250 Labeled “C
”
10
0-25 200 Labeled “S
”
500 250 Labeled “C
”
10
0-50 200 Labeled “S
”
500 250 Labeled “C
”
10 or 25
0-100 200 Labeled “S
”
500 250 Labeled “C
”
25 or 50
0-150 200 Labeled “S
”
500 250 Labeled “C
”
25 or 50
0-500 80 Labeled “S
”
1000 100 Labeled “C
”
100
0-1000 200 Labeled “S
”
500 250 Labeled “C
”
100 or 250
0-5000 200 Labeled “S
”
800 250 Labeled “C
”
1000 or 2500
0-10,000 80 Labeled “S
”
800 100 Labeled “C
”
2,500 or 5,000
0-5% 200 Labeled “S
”
1000 250 Labeled “C
”
1% or 2.5%
CAUTION: Verification of the correct calibration gas level setting and calibration span gas
concentration is required before “span” calibration. These two numbers must be equal.
Span Calibration consists of entering the calibration function and following the menu-displayed instructions.
The display will ask for the application of span gas in a specific concentration. The concentration must be
equal to the calibration gas level setting. See Table 3 Sample Flow Rate above for recommended cal gas
concentrations. Other concentrations may be used as long as they fall between 10% and 90% of range.
However, any alternate span gas concentration value must be programmed via the calibration gas level menu
before proceeding with span calibration. Follow the instructions below for span calibration.