Edwards PGC201, Instruction Manual

Page: 39 / 68

D0300040001EN - Parameters
Page 29
Parameters
Switching function parameters (

)
In this parameter group you can configure the switching functions. The PGC201 provides the
following switching function parameters:
Basic terms
Switching functions
The PGC201 contains 6 switching function relays, that is, 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 (see
Relay output (relay output) ).
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 (SP1
Lo
, SP2
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 (SP1
Hi
, SP2
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
(see
Figure 13 ).


Switching function 1 low switching threshold


Switching function 1 high switching threshold


Switching function 2 low switching threshold


Switching function 2 high switching threshold