fingerlakes
Member
XIC (or the corresponding symbol, regardless of brand) is an INSTRUCTION, not a contact. It instructs the processor to check the state of a bit in memory - looking for a 'one'. When I was learning PLC, I actually taught myself to refer to the XIC as the "look for a one" instruction.
XIO is therefor the "look for a zero" instruction.
For folks that INSIST on referring to these 2 instructions as "normally open" and "normally closed", have them draw the ladder logic to "seal in" an output instruction, with a normally open start button and a normally closed stop button.
That single example should break them of the habit and provide the ultimate "aha!" moment.
XIO is therefor the "look for a zero" instruction.
For folks that INSIST on referring to these 2 instructions as "normally open" and "normally closed", have them draw the ladder logic to "seal in" an output instruction, with a normally open start button and a normally closed stop button.
That single example should break them of the habit and provide the ultimate "aha!" moment.