Item - Step Master Slave

Please refer to Adding a New Item for specific information on how to add an ITEM and how to change its properties.

Description

The Step Master Slave ITEM is the main ITEM when setting up a Step Control that is to run in "Slave" mode to another Step Master ITEM.

The "Slave" Step Control is to be contained within one TASK, each TASK having only one Step Control. The "Master" Step Control would be in its own TASK. Each "Slave" Step Control would in turn be in its own individual TASK.

Each "Slave" Step Control is to have only one Step Master Slave ITEM.

The Step Master Slave ITEM will search the TASK it is in and find all of the other Step ITEMS. It will search each ITEM in its own TASK in order from first to last. The first Step ITEM found will become the first step, the second Step ITEM found will become the second Step and so on.

When the "Slave" Step Control is run, it will get the relevant information from each respective Step and from the "Master" Step Control.

Remember to ensure that all of the Step ITEMS are placed before the Step Master ITEM. This will mean that as the TASK is updated the Step Items , and their respective supporting ITEMS, will be updated first so that when it is the Step Master 's turn to be updated it will have access to the very latest information from the Step ITEMS and their supporting ITEMS. For more information on the sequence in which ITEMS are updated refer to Overview Operation. Also for best results position the "Master" Step Control TASK before the associated "Slave" Step Control TASKs.

Properties
Class Name A unique name for this item. The class name is display only and cannot be changed.
Name Enter a meaningful name for this Item so that you, and other people, will easily recognize what it is for.
Enabled No - The ITEM is not enabled and will not update when its TASK updates

Yes - The ITEM is enabled and will update when its TASK updates.
Step Master Select the ITEM that is the Step Master.
PV Input Select the ITEM that is getting the PV.
Step 1 PV Start Select either option:

No = When the Step Control starts the starting Set Value will be "Step 1 SV Start" listed below.

Yes = When the Step Control starts the starting Set Value will be the set to the value of the current PV.
Step 1 SV Start Set the Set Value that will be used as the starting Set Value for the Step Control.

Note: Only used when "Step 1 PV Start" above is set to "No".

SV Output Select the MicroScan Output Tag for the Set Value.
On PC Restart Step Control OFF - Stops the Step Control when the PC Restarts.

Step Control Resume - Resume s the operation of the Step Control to what it was the last time the TASK was updated when the PC restarts.
Dev Alarm Output Select the MicroScan Output Tag for the Deviation Alarm.

The Deviation Alarm will alarm if it is enabled within the current Step and if the PV has been outside the limits for the time specified by the "Dev Alarm Delay".

The "(Gua) Dev Hi" and "(Gua Dev Lo" limits and the "Dev Alarm Delay" values are specified in the current Step.

  

Notes

  1. All properties that reference other ITEMS do so for flexibility. The other ITEMS may be fixed values using the Math Value ITEM, or they may be variable by using say the In Input Tag ITEM which could be reading data from the "MicroScan Image Interface" that can be changed by an operator via the Mimic program.

 

 Back to Items Index

 Back to Contents