Most MES Objects have specific events that are fired during the life cycle of the object, such as object creation New which fires every time a new instance of the object is created. Events provide the ability to add custom scripting for your application based on certain events. As an example, the Material Lot object has an event every time a new lot number is generated. You could use this to modify how lot numbers are generated.

Events can be viewed and edited from the Production Model section of the Ignition Designer. Whenever an event is fired, an MESScriptEvent object is passed to the event. You can use this object to get information about the event and the object.

Event Types

There are two types of MES Object events, system events and custom events. System events are provided by default and cannot be deleted. Custom events can be created by right-clicking in the MES Events table and selecting New. Script can be added for both system and custom events in the Production Model section of the Ignition Designer to alter what happens when these events are triggered. 

Custom events can be created by right-clicking in the MES Events table in the Production Model section of the Ignition Designer and selecting 'New'. These events will only fire whenever they are called using the system.mes.executeMESEvent scripting function.

Adding Scripts to System Events

Scripts can be added to change the standard behavior of system events and add functionality when custom events are triggered. This is also done in the Production Model section of the Ignition Designer by right-clicking on the event and selecting 'Edit'.

 event.runDefaultHandler()

to the custom script.

#Get the object associated with the event 
obj = event.getMESObject()
 
#Read the parameter passed in to the event
kind = event.getParameters().get('Kind')
 
#Based on the kind parameter value, add the appropriate custom property to the MES object.
if kind == 'Bulk':
	obj.addCustomProperty('Avg Width', 'Float4', 'Average Part Width', 'mm', True, False)
elif kind == 'Single':
	obj.addCustomProperty('Actual Width', 'Float4', 'Actual Part Width', 'mm', True, False)

system.mes.saveMESObject(obj)

MESScriptEvent Object

Whenever an event occurs, an MESScriptEvent object is passed to the script window. The following object functions are provided to allow you to access the MES Object itself as well as execute any default behavior.

MESObjectEventParameters Object

This object is used with the MESScriptEvent object to pass parameters to the MES object event and holds name value pairs where the name is a string and value is any value type of object. This object is typically used when executing user MES object events to allow passing values to the event script. The system.mes.object.parameters.create() script function can also be used to create a new instance of this object. The following object functions are available:

#Create a new parameter collection instance.
params = system.mes.object.parameters.create()
 
#Add parameters to it.
params.put('Kind', 'Dressing')
params.put('Priority', 'High')
 
#Print the parameter values
print params.get('Kind')
print params.get('Priority')
print params.get('Type')

Dressing
High
None

#Create a new parameter collection instance.
params = system.mes.object.parameters.create()
 
#Add parameters to it.
params.put('Kind', 'Dressing')
params.put('Priority', 'High')

#Create a new parameter collection instance.
params = system.mes.object.parameters.create()
 
#Add parameters to it.
params.put('Kind', 'Dressing')
params.put('Priority', 'High')

#Print the parameter values.
print params.size()

2