Process Variable

The Process Variable represents the measured value or parameter of a particular part of a process which is being monitored and controlled.

Usually, a process variable is linked to a PLC tag, where actual values are being referenced.

To create the process variable definition, go to Settings > Configuration > Process Variable:

Click Actions > Create; you will be presented with a pop up.

Complete the following fields:

Name (mandatory) - the text name of the process variable.
Unit of Measure - this will open a drop-down selection; the value entry comes from the UoM configuration.
Description - a text description of the process variable.
Constraint Min - the minimum numeric value, that prevents the submission of an activity, if not met. Usually, this is below the Lower Limit.
Constraint Max - the maximum numeric value, that prevents the submission of an activity, if exceeded. Usually, this is above the Upper Limit.
Display Order - defines the order in which the entry will be displayed in the selection.
Decimals - represents the precision of the number entered. If this value is set, TilliT will round the number entered to the nearest decimal place.
Target - the optimum numeric value which, if controlled, can guarantee compliance with the process operation. If both Upper Limit and Lower Limit are left blank, you must meet the Target precisely.
Upper Limit - the the maximum numeric value of a measured asset variable where, if exceeded, will have a potential effect on the process operation.
Lower Limit - the minimum numeric value of a measured asset variable where, if not met, will have a potential effect on the process operation.

Click the Save and Close button to finalise the entry.