How to capture value from variable in ST

Hi,

I want to capture a value from variable A (e.g Temperature) when certain conditions are met and write this value to another variable B. Variable B should only contain captured value until the next time conditions are met and value is written.

Variable B indicates that when a certain condition occurred the temp was xx.

I am using OpenPCS and programming in ST.

Thanks in advance.

Regards,

If you want to capture the variable as long as condition is true:

or if you want to capture the variable only the moment condition turns TRUE:

Another way to capture only when the condition becomes true would be to use a rising trigger function block (R_TRIG). The .Q value of this block is true for one scan only after the condition becomes true: