Limits in the Runtime

For binary variables zenon reacts on reaching the status (positive edge). For numerical variables the control system reacts on reaching or violating the defined maximum (equal or bigger) and reaching or violating the defined minimum (equal or smaller). Thsi is called a limit violation.

Info

A binary variable has two limits, a Min limit and a Max limit. Care that: Enter the Min limit as limit 1, and the Max limit as limit 2.

At the calculation of limits of numerical variables, the raw value of the variable (signal resolution) for the use in zenon is always calculated in a linear way unless it is defined differently with function 'non linear value adjustment".

Example: A temperature sensor sends its value to the control. The corresponding byte variable has a signal resolution of 0...255. In zenon the corresponding variable has a meassuring range from 0..100. Hence:

PLC	Control system
0	0
127	50
255	100

If a limit is violated, when zenon is started, the reaction is executed immediately on starting the Runtime.

Exception:If the reaction should be an entry in the alarm or CEL list, the system first checks whether the entry already exists from the previous session. If this is true the entry is not done again! So double entries are avoided. All other reactions are nevertheless executed.

Attention

Only one limit of a variable can be active at a time.

More information on measuring range and signal resolution can be found in the properties help.