External Boolean Module
If you want to disable a module under certain circumstances, you can link its Enable input to an External Boolean module that you can switch to off.
External Boolean modules have no inputs; they are controlled via communications.
This register allows you to assign a priority level to the events produced when the output register is written. When EvPriority is zero, no event is written.
All External Boolean modules have a single switch register which can be manually switched on or off via communications.
All events produced by an External Boolean module are written into this register. Possible events and their associated priority numbers are shown in the table below.
|Event priority group||Priority||Description|
|Setup Change||10||Setup register or labels have changed.|
|Output Value Written||*||The Switch output is written.|
|* The priority of this event is determined by the value in the EvPriority setup register.|
The Event output register stores the following information for each ION event: time stamp, priority, cause, effect, and any values or conditions associated with the cause and effect.
Responses to special conditions
The following table summarizes how the External Boolean module behaves under certain conditions.
|Condition||Response of output registers|
|When the device is started or powered-up (either the first time, or after a shut-down).||The Switch output register retains the value it held at shutdown.|