PLC can be rebooted in two ways.
- The first one is warm restart. Warm restart will use last saved values of variables on the start of the progarm. All variables are automatically saved in the beggining ot the warm restart procedure. Warm restart will restart the program on PLC and the first cycle of the program will use variable values, that were actuall right before the restart.
- The second option is the cold restart. Cold restart will not use any of saved variables. It will use only values that are set as initial values in code of program during solution deployment.
When the default value is set to "True" on the HW digital outputs the output will not close during a cold restart of the PLC.
Use this auxiliary function to set the initial values the block to which you assign, where to assign it to the Def_value_DO variable required HW digital outputs to be set as default "True" on cold restart "
Def_value_DO : BOOL; // Variable initialization
Def_value_DO := TRUE; // Initial value of the digital output
hw.RXIO_DO01 := Def_value_DO; // Assignment of initial variable