GA130001441_002_C0
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7.
Parameters
7.1
Switching Function Parameters (PArA SP)
In this parameter group you can configure the switching functions. The COMBIVAC CM 51
provides the following switching function parameters:
SP1-Lo
SP1-Hi
SP2-Lo
SP2-Hi
7.1.1
Basic Terms
Switching functions
The COMBIVAC CM 51 contains in all 6 switching function relays, i.e. the switching functions
1 and 2 are available for each measurement channel. These switch depending on the
measured pressure. The contacts of the relays are floating and may be used for switching
purposes through the connection marked Relay Output (
Chapter 5.3.9 Relay Output
(Relay Output), Page 23).
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 19, page 34).
