Ladder logic for 2-hand ATD

[waggs]

With a few pointers I can try to import the logic or screen. Not sure what I'm doin yet, but I'll see what I can do.

Bob

 

[waggs]

2hATD screen shot...hope this worked

Here is a screen shot of the logic that I use. Hope this works.

Bob

 

[flexdmc]

I think it should be C: not c;
Please re-post?

 

[waggs]

I've tried everything...well, not the right thing!~!~!

OK...I can write a program but I can't post a picture...

 

[waggs]

What does this button do

 

[CaseyK]

By George, err Bob...You've got it.

All comes to he that waits, or something!

Take the rest of the night off with pay....casey

 

[gaannesh]

pdf

Here is a short program of 2hATD that I've used alot. It isn't fancy but it does take into account two hand actuation and timed interlock(?) between the two PBs'. Depending on the use, we were making small component assembly machines, anti-repeat was added by looking at both PBs' having to be released, i.e., 'cycle complete'. Like I was taught, there are 1000 ways to skin a cat, you just have to find the one that makes the least mess. Hope this helps...I'm open to suggestions and ideas.

Bob

Please can you give the code in pdf

 

[gaannesh]

i wish to get anti tie down anti repeat HARDWIRE CIRCUIT

 

[iant]

there are a few ways
- use a Pilz or equivalent, two button safety relay
- hardwire with or with out timers (not 100% because the timers can be set too high.

the basic tie down requires each button to be wired separately.
- remember you want to know that each button has been released - so you can not wire them in series.
basically when one button is released it needs to energise a relay. PB1 - RLY1 and PB2 - RLY2
the N.O. contacts of those relays need to close to allow the start cct to commence.
Then as the cycle stops you dropout RLY1 and RLY2
that forces the operator to release the both PB1 and PB2 before a restart can happen.
timers can be used to ensure that the buttons are pressed at the right time. BUT they can be set by external people - so not that safe

 

[Steve Bailey]

Nine year old thread alert. Several of the participants have not been active in years. At least one of them is no longer alive.

 

[iant]

thanks Steve, I had noticed, But Gaannesh had also PM'd Me
this was easier

Gaannesh would you mind starting a new thread rather than continuing with this one

 

[James Mcquade]

the timer should be set to trip in .3 seconds, although we have used .5 seconse. .3 seconds is to fast.
one thing you MUST consider is that the pushbuttons must have a way to be checked in the plc for release and contact breakage. that's what an anti tie down module looks for.

for example, banner otba5 pushbuttons (if my memory isn't faulty) has a set of n.o. and n.c. contacts.

regards,
james

 

[iant]

the timer should be set to trip in .3 seconds, although we have used .5 seconse. .3 seconds is to fast.
one thing you MUST consider is that the pushbuttons must have a way to be checked in the plc for release and contact breakage. that's what an anti tie down module looks for.

for example, banner otba5 pushbuttons (if my memory isn't faulty) has a set of n.o. and n.c. contacts.

regards,
james

Gaannesh has posted here instead of starting a new post.
So it is not directly related to the 2004 post

A few things you missed.
1 it is a hard wired system. No plc
2. Any exposed timer can be adjusted by unknown people
3. This is an anti repeat that gaannesh has asked for.
Not a cycle start

 

[iant]

THIS THREAD HAS BEEN RESTARTED BY GAANNESH
http://www.plctalk.net/qanda/showthread.php?t=83764