Gonnheimer Elektronic F870S, User Manual

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F870S 2 Pressurized enclosure system F870S Page 7
Gönnheimer Elektronic GmbH Tel.: +49 (6321) 49919-0 Fax: +49 (6321) 49919-41
2.3.2 Enlarged, free programmable range of operation
In comparison to common Ex p control systems, the FS870S offers an increased and free
programmable range of operation (characteristic pressure / flow curve).
The conventional systems are characterized by a fixed pressure / flow curve (see e.g.
FS850S) with an offset, caused by the opening pressure of the passive mechanical outlet
valve. This typical opening pressure (2... 4 mbar at standard systems) is required to mini-
mize the system leakage rate during normal operation.
Fixed curves by control
devices with flow meas-
urement with plate orifice
Figure 3: Range of operation
The input and output sided PID-control loops allow the FS870S to perform in the whole
range of operation (see figure 2).