Would appreciate help with ladder problem

[dmodiano]

I have attached a copy of a ladder diagram which is supposed to control the opening, closing, and stopping of a garage door. It's suppose to stop when the button opposite the direction the door is moving is pressed. Instead, I'm having it reverse direction. Can anyone tell me how to correct this?

Thank you,

Dan Modiano

 

[Eric Nelson]

I have attached a copy of a ladder diagram

but it didn't make it...

I'm guessing that you attached the file, but then previewed your post (previewing is a a good thing!). But previewing un-attaches the file (any way around this Phil?). Just remember to attach your file only after you're done previewing and are ready to click "Submit Reply"...

If you aren't sure what I mean, try practicing in the "Practice Posting Here" forum

beerchug

-Eric

 

[Phil Melore]

Re: Re: Would appreciate help with ladder problem

but it didn't make it...

I'm guessing that you attached the file, but then previewed your post (previewing is a a good thing!). But previewing un-attaches the file (any way around this Phil?). Just remember to attach your file only after you're done previewing and are ready to click "Submit Reply"...

Hi,
Thanks for pointing out the bug.
Let me find what's causing it and correct the code.
Enjoy,
Phil

 

[Doug_Adam]

Dan,

I have come accross similar problems before.
Although your code didn't make it I would guess the problem lies in either:
1, Latching, you must latch to make you door stop, then allow it to reverse on the second push.
2, Debounce, often switches will 'bounce' giving multiple ON pulses before settling down to fully on. If the PLC is scanning fast enough, it will see multiple pushes of the reverse button and go into the reverse direction (assuming the latching is working). One way around this is to use timers in a delay on/delay off manner. Often 100ms on/off is enough.

Another method may just be to add a STOP button.

Hope this helps,

Doug

 

[Phil Melore]

Although your code didn't make it I would guess the problem lies in ...
--snip--

dmodiano's post with attachment is here:
click here to see his post

Sorry for the confusion. I'm working on the bug now.
Enjoy,

 

[Phil Melore]

bug fixed

Hi,
The bug has been fixed. Thanks for pointing it out and please continue to do so in the future.
Enjoy,

 

[harryting]

Humm... I am assuming it's Allen Bradley Stuff. If so, why is that OSR doing on rung 5? Look totally out of place. Zap that first of all. I would put the OSR right before the latching of the Stop Mode.

A bit used for a OSR (again, assuming AB) should only be for that instruction and no where else so when I see you use a real world Output bit there for OSR... just dont' look right.

back to work before the boss fire me...

HT