RS 5000 programming questions

hello all,

Can anyone help me figure out this problem?
I have a subroutine for controlling diverter valves on three levels: 401L, 1401L & 2402L. The control is same for all three levels. The diverter valve of each level has 2 directions. For example, the 401L one has 600L direction and 1401L direction. Each direction has a limit switch indicating the fully open status. Normally, the valve will be fully open within 30 seconds. I used a TOF timer to shut down the motor if the LS wasn't fully open within 30s, and set a switch_not_ok tag. I tried TON timer, OSF, OSR. All seems not working.
The rung 0 to rung 3 of the attached file is my test rungs. Rung 14 to 23 is the typical 401L diverter valve control.
What's wrong with my program? Any suggestion?

Thanks in advance,

Eric

use the ton timer on the same rung as your start bit(which im guessing remains true while your running). put an xio after the start and reference the valve. If the vlave opens itll stop the and reset the timer. use a latched output for the timer finishing and that will indicate the problem with the valve/stop process.

Hi Luke,

Thanks for help. My start bit is a momentary button on the HMI screen. I'll find a way and try first to see if it works or not.

Thanks again,

Eric

NSong said:

Hi Luke,

Thanks for help. My start bit is a momentary button on the HMI screen. I'll find a way and try first to see if it works or not.

Thanks again,

Eric

Click to expand...

If its momentary you will need to create a seal in rung so that you have reference for the timer to run. Otherwise your timer will reset when that rung is false.

Hi Luke,

Just tested your suggestion. It works.
Any comments about my using of OSF(OSR)? I just start to learn PLC, not quite sure my mistake.

Thanks,

Eric

Eric,
I don't think using an OSF/OSR is bad, but I would question using it when you need retention of the bad condition or when you require an operator to acknowledge that there is an issue. You could use it to latch a bit but then you're creating an extra rung anyways.

Cool to see your project working.