13
After the end of the purge phase, the non-Ex units in the enclosure are switched on. The
overpressure in the enclosure then constantly monitored for adherence to the setpoint value
(factory setting: 2.0 mbar) and also for transgressing of the MIN value (factory setting: 0.8 mbar)
and exceeding of the MAX value (factory setting: 15.0 mbar). Normal operation is indicated by the
message.
Gehäusedruck
xxx.x mbar
Cabinet pressure
is
xx.x mbar
Fig. 3: General function
T1:
T1: When the mains voltage and the compressed air supply are applied, the functional test (self-
check) begins, followed by the purge process of the EEx-p enclosure with a quantity fo air
corresponding to at least five times the enclosure volume.
T2: The purge process has ended. The specified internal enclosure pressure (see Chapter 5
“Parametrizing the Controller“; here 2 mbar) is attained. The units inside the EEx-p enclosure
are activated.
T3: Normal operation begins. The internal enclosure pressure (see Chapter 5 “Parametrizing the
Controller“; here 2 mbar) is regulated at the setpoint value.
in the display.
Fig.3: General function