X20 system modules • Counter modules • X20DC2395
820
X20 system User's Manual 3.10
4.11.14.12.6.4 Comparator functions
The ABR and AB encoders and the up/down counter have a comparator function. It always works the same and
is described here globally for all three.
The comparators are implemented in software form. They do not work actively but rather passively, i.e. the com-
parison is only carried out when an event is received. The event received is forwarded along the TRUE or FALSE
branch depending on the status of the comparator condition. An event function like this generally also offers a latch
for the TRUE and FALSE branch to save the value used for the comparator at the time of the event.
Comparator modes
Comparator functions can be operated in 4 different modes.
•
Off
Events are ignored.
•
Single
The event function is executed once and then disables itself automatically. To re-enable it, the "event
function mode" must be changed, preferably to "off" and then to the desired mode. This setting allows a
hardware latch to be simulated.
•
State change
The event function only responds when the comparator status has changed, i.e. from false to true (or vice
versa). Only the first event for each status is processed, e.g. the first "true" of a sequence of events with the
comparator condition "true". After the event function is enabled, the first incoming event is used to determine
the starting status and therefore not forwarded. This setting allows a hardware comparator to be simulated.
•
Continuous
Each incoming event is forwarded to the true or false branch depending on the comparator condition. This
setting allows event filters to be created.
Configure event ID for comparator
Name:
Counter function 1: CfO_Counter1event0IDwr to CfO_Counter1event1IDwr
Counter function 2: CfO_Counter2event0IDwr to CfO_Counter2event1IDwr
This register holds the event ID that should trigger the counter event function. For a list of all possible event IDs,
see 4.11.14.12.5.1 "List of event IDs"
Data type
Value
Information
INT
192 to 7,233
ID of counter event function
