When a BpmProcessDefinition has a timer in StartEvent then each time the timer answer [true] then a BpmProcessInstance of that process has to be created.
The OS Process compare all process definitions that are being monitored with created process instances and evaluates the timer to created another instance or not. Blocks receive two parameters when the evaluation is done: 1) lastExecutedTime - [aTimeStamp] with the last executed time. 2) currentTime - [aTimeStamp] which is the current time. In the example below aBpmProcessInstance is created each day.
Monitor Each BpmProcessDefinition timer is compared with the last BpmProcessInstance creationTime.