Hello,

I'm back with more questions. I'm programming a small game for the PLC. For timing reasons, I need the buttons to be triggered on the falling edge of the push. However, RSLogix5 has those commands unaccessible - rather, they show up on the command menu, but they are grey-ed out so-to-speak and I can't use them. What's the deal with this?

Never mind. I figured out that my processor doesn't support it. If I ever have only a limited number of buttons to use, I'd be out so of luck.

actually your PLC-5/25 processor would be able to handle up to a maximum of 1,024 "buttons" or other types of discrete (on/off) inputs ... that's the number of bits you have on your input table ...

same thing for discrete outputs ... you could handle up to a maximum of 1,024 of those too ...

squeezing these maximum values out of your system would take some crafty management in the hardware installation department ... but theoretically, those are the upper limits ... I'd say you have plenty of horsepower to play around with and to learn with ...

as for your "problem" ... since you don't have an OSF (One Shot Falling) available, try using an ONS (One Shot) instead ... just don't use an XIC (Examine If Closed) upstream of the ONS ... try using an XIO (Examine If Open) instead ... experiment with that arrangement and see how much you can learn ...

basic idea: you should be able to make your "classic" processor do just about ANYTHING that a newer "enhanced" one will do ... it just might take some extra effort and imagination on your part ...

best regards,
Ron