CCW timer bits

Hi folks

I received an AB 820 micro from a friend who is an electromechanical wizard but was so frustrated trying to program it that he gave it to me and said "see if you can figure it out"

I had never seen a PLC before last week, but I have been obsessed with this thing since he brought it here.

He wants to have a door open when a limit switch is triggered by a feed cart and auger motors fired up. First the auger outside the door to clean it out and then 5 seconds later fire up the internal auger behind the door to continue loading the outside auger. There is a load limit switch on the outside auger, to prevent it from overflowing in case of a jam, that needs to pause the inside auger for about 15s while the outside auger keeps running to clear the load.

There is a start sequence for both augers on this rung(rung 6) that I don't want to run if the 15s delay timer in the earlier rung (rung 2)is active.

I thought I could use a TON timer bool bit from TON10 to indicate to rung 6 that the timer on rung 2 is active but it doesn't seem to be working for me. I have tried contacts/reverse contacts pointing to the IN and the Q but it doesn't seem to matter... the timer is ignored and the rung 6 is true every pass. Feel free to point out as much of my ignorance as you can

As an aside can anyone recommend the best book I should buy to start out with? Or a good online training course. I have gotten this far by reading whatever resources I can find online but there doesn't seem to be a lot of stuff for CCW.

Thanks for all and any input for this absolute neophyte.

Mongoid

Use a XIO TT bit from timer 10, if this is RS logix software.

can you zip and post your program please
or
increase the size of the PIC I cant read it

IIRC there is no such thing as a .TT bit in the Micro timers You have to make it yourself in ladder logic. I can't remember how and I tried a google search and didn't find anything .

It wasn't much of a deal, but I don't remember how... surely one of these gurus on here can come up with something to tell when a timer is timing.

BTW ...the CCW and micro will drive you nuts, but by the time you are done you will probably like the stuff... perhaps a manifestation of being nuts

realolman said:

IIRC there is no such thing as a .TT bit in the Micro timers You have to make it yourself in ladder logic. I can't remember how and I tried a google search and didn't find anything .

Click to expand...

EN and DN in series should work. One XIO and the other XIC.

I know that the .TT bit is common place with almost all of AB products.
personally I would ignore this bit as 99% of other PLC's don't have it.

The use of terms XIC and XIO is also AB specific and NOT used in their
(maybe not AB) 800 series

My gripe sorry

welcome to the site, by the way

Mill_Control said:

EN and DN in series should work. One XIO and the other XIC.

Click to expand...

I believe you are right... it seems to me that this would work
I'm sure you are thrilled to receive my endorsement ;/)

This is AB's solution. Knowledge base 496685

TT=EN and not DN. If the timer is enabled and not done, then it must still be timing. Sometimes you have to make your own EN bit too. So, for the above to work, the .REdge is the same as the EN? It is true as long as the timer is enabled?

I believe .REdge is essentially the same as RSlogix 500 & 5000 EN

Thank You Matt

First off sorry about the late reply and sorry about the pic quality of my very first post. I have posted what I hope is a better pic and a better version of the ladder I'm working on. This is my second ladder program. The first was the ol' traffic light one. It used a function block in the program so I was trying to do the same thing initially until I found the debug view from a ladder in the program. Also actual I/O's with an alias have been added. My problem has been with the delay rung when the high level sensor fires. I think Matt has helped me here and I will rethink it. If you folks see anything that's considered bad form or just plain dumb please let me know. I had read for instance that set and reset coils shouldn't be used if direct coils can?

Thank you so much for that find Matt. I was wondering if I would have to create my own variable but couldn't put it together. The rising edge is the EN bit. The shown solution has opened another door for me. I was trying to use IN as the EN bit.

Might there be a way to use ET as a DN bit? I realize its not Boolean but when ET = PT the timer is done. I'm far too ignorant at this point to figure it out in this software.

Thanks again for all your input folks,

Mongoid

you can name your timers ... that might be helpful

in rung 5 you have conditions for starting auger 1... then those same conditions are repeated in other rungs... if you used a bit for auger 1 running you could save some elements and maybe make the logic a little easier.

I dunno if the timer in rung 8 is going to do anything or not... depends upon what resets level high... I assume whatever is being augered is being used (level lowered) and if the level resets the level high bit before 15 seconds, the timer might keep it from coming back on, if I'm seeing this correctly. ( I think you have to reset these timers in CCW , don't you) and I just now see that that is a NOT Q bit so, I dunno what it would do... auger 2 might never come on at all ??

I assume you want to keep the auger 2 from running for 15 sec once the level high is set, so it's not on and off all the time... You could set the level_high and have it enable the timer, the timer could keep the auger running for 15 more sec, I guess... or have the level_high set the timer and the timer reset itself AND level_high... but those kinds of things are for you to figure out... that's where the fun is... if it was just a bunch of mindless typing, it wouldn't be any fun

Wouldn't the Q bit be equivalent to the DN bit?

Yes Q is the done bit

Some clarity

Hi folks,

The process is supposed to be like this:

When a robotic feed cart rolls up to the limit switch, the door to the silo should open. If the motor is on for the door, the auger outside the silo(Auger_1) that loads the cart should fire up and run for a set time to clear the auger. The times I have used are greatly reduced at this point for simplicity of testing.
If the limit switch that indicates the silo door is fully open is engaged, start the auger inside the silo(Auger_2) and begin loading Auger_1.
If all goes well the existing robotic feed cart is programmed to move off the robot limit switch and wait for 40 seconds. The cart leaving the limit switch starts the shutdown for the augers. Auger 2 shuts down, the silo door closes and auger_1 runs on to clear the last of the load into the cart before the cart moves onto its run around the barn.

The safeties I have thought of so far would include a shutdown after an overall runtime, a high level sensor on auger_1 and a limit switch to indicate the silo door is fully open and not jammed.

If the high level is true, auger 2 should shut off and stay off for 15s even if the high level is no longer true. I have included a timer that will shut the system down if the high level stays on constantly for a set amount of time.
Finally if the silo door doesn't hit the limit switch after set time the system is shutdown.

I guess the thing I'm having a hard time wrapping my head around is having the high level sensor stay on for a set amount of time to allow auger_1 to clear the load. The way it is now if the timer is triggered the auger_2 will shut off but only as long as the sensor is triggered. This will lead to the sensor triggering the auger on and off repeatedly if the auger_1 is not given enough time to clear the load. Is there a way to force the high level input to an on state for a set amount of time by way of an output?

I have not labelled the timers yet but that is a good suggestion and I definitely will on the next write.

Is using reset coils the correct way to force the shutdown?

Please let me know if I'm doing anything here that is not good form. I want to correct as many misconceptions and bad habits as soon as possible.

Still wondering if anyone can recommend a current textbook that I should buy?

Thanks Folks

@realolman

Thanks, yes you have it exactly. I wanted the either the level high to stay enabled; in which case the timer would be allowed to stay enabled, or the auger2 to stay off for fifteen seconds even though the high level is no longer being activated.

I believe the timers are reset when the IN changes state. That's why my extended delays haven't been working.

Agreed on the fun bit