Hi,
I'm new in PLC programming and I'm hoping to find a solution to a programming task, hopefully, I can get some help from anyone of you who is kind enough to take my case.
The purpose of this function is simple, from SCADA, write and save a variable to the PLC.
The programme that I wrote in the PLC (please see figure below) currently counts the number of hours that a device was used, it can also be set to zero in case a new device is physically installed in the machine. However, if a second-hand device with a lifetime of 700hrs consumed is installed, the counter should start from 700hrs instead of 0 hrs. So my question is, how do I create a "writable" function that takes a variable so I can add it to the current programming as an option. Hoping somebody could extend a helping hand, thank you.
