Calibrating the Sensing Head
Polytron SE Ex
To achieve the state of thermal balance, the sensing
head needs to be in operation for at least 30 minutes
(warm-up time) before starting the calibration proce-
dure.
Zero Adjustment
Without calibration adapter:
Make sure that the sensing head is in clean air (free
of combustible gases and vapours),
or, with calibration adapter:
Apply zero gas (clean air or nitrogen) to the sensor
via calibration adapter, flow rate approx. 0.5 L/min.
Controller Unit Polytron with Channel Module
Polytron SE Ex:
1, 2 For channel mod-
ules without ana-
logue indicator or
with bar graph dis-
play connect volt-
meter
1 MOhm) to
(R
i
the sockets.
Sensing head Polytron SE Ex PR M1/2/3 DD, SE
Ex PR NPT1 DD and Polytron SE Ex HT M DD:
0 to 4.7 V correspond to a measuring range of
0 to 100 %LEL; so 1 %LEL = 47 mV.
Sensing head Polytron SE Ex LC M1/2/3 DD and
Polytron SE Ex LC NPT1 DD: 0 to 4.7 V corre-
spond to a measuring range of 0 to 10 %LEL; so
1 %LEL = 470 mV.
3
Use zero potentiometer to set indicator to 0 %LEL
(0 mV at voltmeter).
Controller Unit REGARD with Channel Module
REGARD Ex:
By means of menu »10-0 ZERO« set zero signal.
Please refer to the Instructions for Use REGARD Ex.
mV
=
1
2
3
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 sen-
sor, flow rate approx. 0.5 L/min.
Recommended span gas concentrations::
Sensing head
Polytron...
SE Ex PR M1/2/3 DD
SE Ex PR NPT1 DD
SE Ex HT M DD
SE Ex LC M1/2/3 DD
SE Ex LC NPT1 DD
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 min-
utes):
Controller Unit Polytron with Channel Module
Polytron SE Ex:
4
Set the analogue
indicator with the
sensitivity potenti-
ometer to the val-
ue corresponding
to the span gas
concentration.
Sensing heads Polytron SE Ex PR M1/2/3 DD, SE Ex
NPT1 DD and Polytron SE Ex HT M DD: 0 to 4.7 V
correspond to a measuring range of 0 to 100 %LEL;
so 1 %LEL = 47 mV.
Sensing heads Polytron SE Ex LC M1/2/3 DD and
Polytron SE Ex LC NPT1 DD: 0 to 4.7 V correspond to
a measuring range of 0 to 10 %LEL; so
1 %LEL = 470 mV.
Examples:
Sensing head Polytron SE Ex PR M1/2/3 DD to be
calibrated with 45 %LEL:
Adjust to 45 47 mV = 2115 mV = 2.115 V.
Sensing head Polytron SE Ex LC M1/2/3 DD to be
calibrated with 5 %LEL:
Adjust to 5 470 mV = 2350 mV = 2.35 V.
span gas
full scale
concentra-
deflection
tion
100 %LEL
40...60 %LEL
100 %LEL
40...60 %LEL
100 %LEL
40...60 %LEL
10 %LEL
4...7 %LEL
10 %LEL
4...7 %LEL
CAUTION
mV
=
4
37