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• Set the upstream pressure of the protective gas (it should be 0.2 ... 0.4 MPa upstream of
pressure regulator).
• Set the pressure regulator of the Ex px safety equipment to at least 0.2 MPa.
When measuring combustible gases with Ex px protection rating with leakage compensation,
you must ensure that the sample gas pressure applied to the analyzer is not more than 164 hPa
(164 mbar) above the atmospheric pressure and is always at least 50 Pa (recommended 5 hPa)
below the protective gas pressure.
If this condition cannot be guaranteed at all times, you must fit a differential pressure monitor
between the sample gas and purging gas as additional protection.
After carrying out the measures described above, you can start up the analyzer by
1. Opening the protective gas path and
2. Switching on the supply voltage
5.3.2
Pressure correction
There is an internal pressure sensor in the ULTRAMAT 6F for correcting the influence of
atmospheric pressure. This is connected to the ambient air by a pipe. To avoid explosive
atmosphere diffusing into the pressure sensor, this pipe must be connected to a hose which ends
in the non-hazardous area.
A higher sample gas pressure up to 1500 hPa can only be measured with an external pressure
sensor. Its signal must be fed into the analyzer in an intrinsically-safe manner. Its parts wetted
by the sample gas must meet the requirements of the measurement. Connection and
parameterization of an external pressure sensor are described in the associated Operating
Instructions.
In the OXYMAT 6F the influence of the sample gas pressure can be corrected by the internal
pressure sensor in a range up to 2000 hPa. A higher pressure up to approx. 3000 hPa can only
be measured with an external absolute pressure sensor.
The CALOMAT 6F/CALOMAT 62F is largely independent of the input pressure as a result of its
measuring procedure (thermal conductivity). It may nevertheless be necessary to compensate
the influence of pressure using an external pressure sensor. An external pressure sensor is also
required if the input pressure is greater than 1100 hPa absolute.
Note
Using external pressure sensors
If an external pressure sensor is used, the internal pressure sensor must be sealed if it is not
connected to the non-hazardous area.
5.3.3
Key switch
The Ex protection of the Ex p safety equipment can be deactivated (key inserted in the lock) using
a key switch (bypass switch). In this manner, the analyzer can also be connected electrically
without protective gas purging, e.g. for maintenance work. Some Ex p safety equipment offers
the possibility of effecting the key switch function with an operating function (key code).
Compact Operating Instructions in accordance with EN 61010-1 and EN 60079-0
Compact Operating Instructions, 09/2018, A5E45779389002-01
5.3 Additional measures for devices in hazardous areas
Commissioning
49
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