In my project, I have a HMI controlling a DL06. Some of the pushbuttons on the panel operate discrete bits inside the PLC, C0-C20. Is there a way to save the last status of these bits to retentive memory? For example, when they power the machine down for the weekend, it will be setup one way. When they power it back up Monday morning, it will be in the "default" state. My HMI is replacing a bunch of old switches and pushbuttons, and updating for some newer information/calibrations. Is there a way I can write the register of V40400 (I think this is the V ref I'm looking for off the top of my head) and then load it on the first scan using contact SP0? I tried this, and it doesn't seem to work.