ML1500 Strange Interrupt behavior

Hey Guys,

So I have a MicroLogix 1500 Ser. C 1764 LRP and using the High Speed input for an encoder. I am experiencing some kind of interrupt but only when my I:0/3 input is on. I'm using switched inputs on I:0/1 through I:0/6 and everything works fine until I turn on I:0/3. Then it seems to freeze the input pulses and just about everything else in the program. I searched the entire logic and came up blank for anything else controlling. If I modify the logic to use a different input, everything works great... So the logic is ok.
Now, I know I can just change a few things in the logic and simply not use this input, but I want to know whats causing this problem.
I want to also mention that the DC Input LED lights up fine when switched on and the input appears to be on in the logic.
Also, thinking that I could have a bad base unit, I also tried switching out the base, no luck.

Why just input 3? Maybe I did something on accident?

Any ideas would be greatly appreciated.

I think you are going to have to post your logic for someone to help.

Zip the .RSS file first then post if you can.

Then it seems to freeze the input pulses and just about everything else in the program

Click to expand...

Can you give a little more info on the above statement.

Are you sing the inbuilt HSC, if so what mode are you using the first 4 inputs are used to control the HSC:0, read chapter 5 of this manual,
1762-RM001D-EN-P, read from page 5-16 this will tell you what the inputs do when you are using the inbuilt HSC's for the different modes available.

Alan