9023744 - 3rd edition - October 2005
Page 15 of 40
Start-Up
Start-Up
● Switch on supply voltage.
Note: switching on the supply voltage may trigger an alarm at the central unit
(see page 8, para. 3).
● Allow transmitter with Ex-sensor to warm-up in this condition for 10 minutes
(sensor warm-up time).
Calibrating Transmitter Polytron Ex
● Use special key to open flap in front of adjusters.
1 Set sliding switch to position »1« = cal.
● The measurement signal of the 4 to 20 mA loop oscillates between 2.5 mA and
5 mA with approx. 1 Hz, thus preventing alarm triggering.
● A further digit appears in the display making it possible to take more precise
readings.
Zero Adjustment
Without calibration adapter:
— Ensure that the transmitter is in clean ambient surroundings, i.e. that there are no
combustible gases or vapours present,
or
— with calibration adapter:
● Supply clean air at a rate of approx. 0.5 L/min via the calibration adapter.
2 Wait for the display to stabilize (max. 3 minutes). Set potentiometer such that the
display indicates 00.0.
Sensitivity Adjustment
— Using commercially available test gas:
● Depending on the Ex-sensor used supply the recommended calibration gas con-
centration (see table below) at a flow rate of approx. 0.5 L/min via the calibration
adapter.
Recommended concentrations:
— The calibration gas must be a mixture of the gas component to be monitored in
air. Mixtures with nitrogen are not suitable!
Once measured value display has stabilized (after max. 3 minutes):
3 Adjust sensitivity on potentiometer such that display indicates the calibration gas
concentration.
Ex-sensor Full scale value Calibration gas concentration
Ex-sensor PR M 100 % LEL 10 to 50 % LEL
Ex-sensor LC M 10 % LEL 3 to 7 % LEL
02023744_1.eps
1
02123744_1_en.eps
1
zero gas
02223744_1_en.eps
3
Test gas
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