Envent 330S-Ex, User Manual

Page: 37 / 71

Envent Engineering Ltd. Page 32 Revision 1
CALIBRATION PROCEDURES
H
2
S Gas Calibration
Depending on the application, the 330S-Ex and 330SDS-Ex H
2
S analyzer will
require more or fewer periodic calibrations. There is no specific time as to
how often the H
2
S analyzer should be calibrated. It will depend on the
application, importance of accuracy for the application, and how dirty or clean
the environment and sample are. The following is the calibration procedure
for the 330S-Ex and 330SDS-Ex H
2
S analyzer:
1. Source a calibration gas of H
2
S in balance of N2 regulated to 15 psi
(check expiry date). H
2
S concentration to be approximately 2/3 of full-
scale range or close to the H
2
S alarm set point.
2. Press the bypass button and verify the "Bypass" LED illuminates (alarms
will be held in the non- alarm state).
3. Turn off all gas supplies to the analyzer and check that a sufficient
amount of H
2
S sensing tape is installed.
4. Press the "Menu/Set" button until "Mtr Run" is displayed. Press the right
arrow [ →], the H
2
S sensing tape will advance for approximately 10
seconds.
5. Press the "Menu/Set" button until "mV" is displayed ("###mV"). If the mV
reading is 1000mV (+100mV), proceed to the next step, otherwise re-
zero sensor (Refer to "Re-zero Sensor Procedure" on page 33).
6. Connect calibration gas to calibration port and turn the 3-way calibration
valve 180°. The valve handle should be pointing towards where the gas
bottle tubing is connected to (Calibration Inlet).
7. Turn on sample inlet valve, ensure that the sample regulator is supplying
15psig to the eductor (make sure there is suction from the eductor
block). Adjust the flow meter to 2.0. Wait until the H
2
S reading has
stabilized (10 to 15 minutes).
8. With calibration gas applied, if H
2
S reading is satisfactory (+2% of
analyzer full range) skip to step 16, if H
2
S reading is not satisfactory a
gain adjustment is required, continue to step 9.
9. Press the "Menu/Set" button until the gain setting is displayed ("###
Gain").
10. Calculate the new gain. New gain value should be within approximately
25% of the gain installed at the factory.