Dräger SE Ex HT M, Instructions For Use Manual, Page: 45 / 60

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Start-Up
Sensitivity adjustment
When using commercial gases for calibration:
●
Depending on the sensing head used, apply span gas with the recommended gas
concentration (refer to the table below) via calibration adapter to the sensor, flow
rate approx. 0.5 L/min.
Recommended span gas concentrations:
The span gas should contain the target gas (gas to be monitored) in a mixture with
air.
Gases mixed with nitrogen are not suitable as span gas!
When the reading has stabilized (after approx. 3 minutes):
Central Controller Polytron SE Ex:
4
Set the analogue indicator with the sensitivity potentiometer to the value corre-
sponding to the span gas concentration.
Sensing head Polytron SE Ex PR M and SE Ex HT M: 0 to 4.7 V correspond to a
measuring range of 0 to 100 %LEL; so 1 %LEL correspond to 47 mV.
Sensing head Polytron SE Ex LC M: 0 to 4.7 V correspond to a measuring range
of 0 to 10 %LEL; so 1 %LEL correspond to 470 mV.
Examples:
Sensing head Polytron SE Ex PR M to be calibrated with 45 %LEL:
Adjust to 45 x 47 mV = 2115 mV = 2.115 V.
Sensing head Polytron SE Ex LC M to be calibrated with 5 %LEL:
Adjust to 5 x 470 mV = 2350 mV = 2.35 V.
Central Controller REGARD Ex:
●
By means of the menu »10-1 SPAN« type in the span gas concentration.
Please refer to the Instructions for Use REGARD Ex.
A calibration chamber can be used for calibration with solvent vapours. This cham-
ber is used to vaporize a certain quantity of solvent, so as to obtain for example
50 %LEL.
Setting is the same as for span gas.
The use of the calibration chamber pre-supposes appropriate training and
knowledge on the part of the personnel concerned.
Pay attention to Instructions for Use of calibration chamber.
Sensing Head Polytron ... full scale deflection span gas concentration
SE Ex PR M 100 %LEL 40 ... 60 %LEL
SE Ex HT M 100 %LEL 40 ... 60 %LEL
SE Ex LC M 10 %LEL 4 ... 7 %LEL
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7_06.eps
mV
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