Offset Events allow you to specify a sequence of events that always occur in a certain order and at a certain time.
Offset Events provide you with a way to expedite any rescheduling that occurs for the sequenced events by reducing the number of calendar entries you have to make for each time the sequence is scheduled to one (1). Needless to say this also minimizes the possibility for error.
Important: Offset events only support one level of offset. You cannot create an offset of an offset.
In the next example, the Kiln_Start event, which is
an offset of Kiln_On cannot have an event that is scheduled
relative to when it occurs. For example, Kiln_Preheat has to occur
relative to Kiln_On (20 minutes prior). It cannot be configured to
occur 10 minutes after Kiln_Start.
Simply said, if you are a programmer—offsets cannot be nested.
For the sake of the example, say your factory has a Kiln. To start this Kiln, you must perform the following events in the following order:
Kiln_Start. Turn on Kiln
Kiln_Preheat. Preheat Kiln (10 minutes later)
Kiln_On_Full. Kiln on Full (20 minutes later)
There are at least three methods to configure your schedule. However, the first is inefficient; the second is problematic; the third is the best choice. See the example below.
Important: Events with offset that wrap around the end of the day are not supported.
You schedule an event for 11:59 PM on March 1 and an offset event of two minutes. The offset event will be scheduled for 12:01 AM on March 1, NOT 12:01 AM on March 2.
Method 1. (Inefficient)
You could easily configure three scheduled events to occur.
7:00 – Kiln_Start
7:10 – Kiln_Preheat
7:30 – Kiln_On_Full
However, if you decide to start the Kiln 30 minutes earlier tomorrow, you need to reschedule three events. Or if you decide that the preheat cycle can be decreased to 10 minutes, you need to move all Kiln_On_Full events back 10 minutes in all of our schedules.
Method 2. (Problematic)
One possible offset configuration is, in the Offset tab of the Event Properties dialog box, to configure the event:
Kiln_Preheat to happen 10 minutes later
Kiln_On_Full to be 30 minutes after Kiln_Start
This way when you schedule Kiln_Start the other two events are automatically scheduled.
The problem with this strategy is that you need the Kilns to be on at 7:30. If the preheat cycle is decreased by 10 minutes you still need to change your schedules to move Kiln_Start forward .
Method 3. (Best method)
The correct solution is illustrated below. In the Offset tab of the Event Properties dialog box, configure the event:
Kiln_On that has no actions.
Kiln_Start to occur 30 minutes prior to KILN_ON
Kiln_Preheat to occur 20 minutes prior to KILN_ON
Kiln_On_Full to happen at the same time as KILN_ON.
Now if you need the kilns to be ready at 7:30 you simply place the Kiln_On event at 7:30.