> how i define Signal Reference??
> how i can send a signal from a service task? can i work with two process in activiti explorer???
You can send a signal from Throw Event by specifying the same Signal Reference as Signal Catch Event.
If you want to a signal from a service task, you can use the following public api.
You specify Signal Reference as signalName.
RuntimeService.signalEventReceived(String signalName, String executionId);
・It is necessary to pay attention to the scope of the signal.
By default, signals are broadcast process engine wide.
If you need to deliver a signal to a specific process instance only, perform correlation manually and use signalEventReceived(String signalName, String executionId) and the appropriate query mechanisms(https://www.activiti.org/userguide/#bpmnSignalEventDefinitionQuery).
・(Reference document)Activiti User Guide 8.2.4. Signal Event Definitions