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GA09037_002_C0
– 09/2016
7.
Parameters
7.1
Switching Function Parameters (PArA SP)
In this parameter group you can configure the switching functions. The multichannel gauge
provides the following switching function parameters:
SP1-Lo
SP1-Hi
SP2-Lo (only with deselected ready function)
SP2-Hi (only with deselected ready function)
7.1.1
Basic Terms
Switching functions
The DISPLAY TWO contains four relays with change-over contacts, from which two for
switching functions and two are available as ready function. The relays for the ready
functions can be used alternatively also for switching functions.
The DISPLAY THREE contains six relays with change-over contacts, from which three for
switching functions and three are available as ready function. The relays for the ready
functions can be used alternatively also for switching functions.
The contacts of the relays are floating and may be used for switching purposes through the
connection marked Relay Output (
5.3.5 Relay, page 19).
Threshold values
The switching behaviour of individual relays is defined in each case through two parameters:
the lower threshold and the upper threshold value of the switching function.
Lower threshold value SPx-Lo
The lower threshold value governs switching on of the assigned switching function. When
the pressure drops below the lower threshold value, then the relay is energised. The
common contact of the relay is then connected to the normally open contact.
Upper threshold value SPx-Hi
The upper threshold value governs switching off of the assigned switching function. When
the pressure exceeds the upper switching threshold, then the relay is de-energised. The
common contact of the relay is then connected to the normally closed contact.
Hysteresis
In the pressure range between the two thresholds, the current relay status is maintained.
Within this range the relay will not switch over and the relay status depends on the history
(
Figure 18, page 29).
