Differentiated inputs

[BenPLC 0]

Hi, I am using CX Programmer 3.1 for a project with a CPM1 brick PLC. I got a compile error as I selected a bit 220.00 to a differentiated bit (text became red, etc.). Is this a version issue or my lack of knowledge of the programming style? I'm accustomed to AB OSR command. . . .that's what I'm looking for. thanks

[Sleepy Wombat 27]

With the CP1A you cannot directly diff up/down an input and I do not believe that the UP inst is compatible either. A couple options.... 1. Have the bit fire a temp bit in a DIFU or DIFD inst and then use that new bit 2. If firing an instruction - ie an INC (increment) you can directly diff on that instruction with and "@" symbol placed in the inst ie @INC