playing with flour!

k,,heres the deal,,4 flour silo's outside feeding two silo's inside,,this question involves the two on the inside,,

at the bottom of each silo,,they are slanted towards the middle where the flour is feed through a rotary feeder to the piping that feeds the machinery on the production floor,,

well,,to break it down,,we have flour silo A and silo B,,where the slant leads to feeder,,it has a pourous membrane material that the flour sits on and under that membrane is a cavity that pressurized by a blower and acts like an air hockey table to keep the flour moving(sliding) down towards the feeder,,without that the feeder would just create a cavity due to the physical characteristics of flour(especially when its humid)and have empty rotary feeders and no flour being plumbed to the mixers on the floor,,since each silo slants towards the center(these silo's are rectangle in shape)and contain an "air hockey" table on each side of the silo slanting to the feeder,,,our blower for the air hockey tables only have the capacity to run 2 tables at a time efficiently,,so with two silos,,we have 4 air hockey tables,,so what we have been doing is having them on timers where two run at once,,in what i labled A/F(silo A/ front),,B/B(silo B/ back) and so on,,

my plan is to put the complete flour system (inside and outside silo's) on a plc with two panelviews,,,instead of the fred flinstone way its done now,,,but this post just addresses the "air hockey tables",,

here is the code i put together so it could switch from blowing air hockey table A/F and B/B to A/B and B/F with a small time gap between each switch,,

if i have done this correctly my code will show up on the screen,,if not,,it may look messed up,,if so,,please forgive me while i try to get it in the post correctly

any insight as to whether this will even work,,ideas on improvement,,points in the right direction on complete redesign,,or just plain making fun of it,,

since i cant seem to copy and paste just that ladder,,ill just put up my whole file,,i know there are alot of errors and its just plain ugly,,(my first ground up attempt),,but its ladder 7 that my question pertains to,,

Fred Raud

FIFO applies here as well. Flour In, Flour Out...

Your timer setup will work, but only once. If you want it to automatically repeat, have a look at THIS post. Very similar.

Am I a hero?...

beerchug

-Eric

Fred,

for us non-AB guys you can print to a pdf file by using PDF 995 .

elevmike said:

Fred,

for us non-AB guys you can print to a pdf file by using PDF 995 .

Click to expand...

downloaded,,thanx alot!

Fred Raud

Here ya go, Mike...

[attachment]

beerchug

-Eric

I'm gonna suggest a counter operation to track the sequence of events. A drum counter indexed by your timers would seem to work well. If you dont have a drum in the instruction set, you can OR all your timers, place a oneshot before a counter, then use the counter to trigger the sucessive timers, which would in turn index the counter etc..

Eric Nelson said:

FIFO applies here as well. Flour In, Flour Out...

Your timer setup will work, but only once. If you want it to automatically repeat, have a look at THIS post. Very similar.

Am I a hero?...

beerchug

-Eric

Click to expand...

I saw that post earlier,,if im not mistaken,,it was involving one of those telemecanique programable relays??i took note of that when i saw it,,cause a few weeks back someone at work handed one to me asking me what it was,,and said it had been on the shelf for a long time and nobody had a clue of what it was,,did,,went to,,etc,,the first thing that came to my mind was to control a lawn sprinkler system(oh yeah,,one of our technicians said the processor in it was probably ok,,but the lcd display was shot,,i fixed the display with some heavy troubleshooting,,modifications,,research,,etc,,,oh yeah,,most important of all,,,i hooked up power to the L and N connection on the unit,,,WTF the tech was doing to power it up, i have no clue,,my little sister could have hooked it up,,

want to be my true hero,,refer me to a good rslogix500 from the ground up book,,,kind of like the "Learn C in 21 days" books(i have about that much time to figure out how to make this whole system work with two panelviews,,two 5/03 processors,,write all the code,,and make it look professional,,and being ive never done a project like this from the ground up,,,and already guaranteed i could do it "no problem",,I have many days of no sleep(i work nights),,to live up to my misrepresentation of my experience and current abilities,,,I just ordered a plc book to replace the one I loaned out and never got back,,but that one isnt rslogix specific,,oh well,enough of my belly aching,,

thanx again,,oh,and youll even earn yourself a Cape if you can get me a 5/03 with at minimum a PV600 so i can start playing with this at home(the only plc at work we have that i can play with is the micrologix 1000 that i had to purchase myself,,,

Fred Raud

PS,,how bad was the rest of the code i had in the other ladders?was i correct that i had to clear the bits when switching silo's(so the plc wouldnt be thinking it was running off of more than one silo???im proud of that forsight!)

elevmike said:

I'm gonna suggest a counter operation to track the sequence of events. A drum counter indexed by your timers would seem to work well. If you dont have a drum in the instruction set, you can OR all your timers, place a oneshot before a counter, then use the counter to trigger the sucessive timers, which would in turn index the counter etc..

Click to expand...

ill do a search on drum counter,,you have me lost,,ill do some searching and post back what i think your telling me,,

Fred Raud

Fred,

Picture a drum, or cylinder with a series of cams on it. With DirectSoft you can have up to 16 lanes, and 16 positions of rotation. As the drum rotates, the cams come in, or off contact with stationary switches (one for each lane). The drum can be indexed by either a timer, or by an event such as a discrete input.

I'm not familliar with AB so I don't know what they exactly call it but AutomationDirect calls it a Drum Counter.

things to think about

First of all, the things you are trying to describe are called air slides in the cement industry. They can also be installed inside
silo bottoms, in which case they are called air-merge slides.

As far as control is concerned, you need to consider lining up
the downstream equipment, and follow with introduction of material.
When complete, the opposite is true, with time between each shutoff,
to empty the path completly.

For instance:
Start blower
Start rotary feeder
Start table air slide
Start air slide
Open silo air merge
Open silo bottom valve
<transfer material, wait for 'full' or stop signal>
Close silo bottom and wait
Close silo air merge and wait
stop air slide and wait
etc.

Don't forget your dust collector on the top of the silo.

Fred, looking at your logic, if you place a XIO (T4:2/DN) in Lad 7, Rung 1, this will creat a repeating cycle routine (symplified below). Eric is right about a one time run, but the added instruction should cause it to repeat.


----------|/|----------------TON T4:0
T4:2/DN


----------| |----------------TON T4:2
T4:0/DN

elevmike said:

Fred,

Picture a drum, or cylinder with a series of cams on it. With DirectSoft you can have up to 16 lanes, and 16 positions of rotation. As the drum rotates, the cams come in, or off contact with stationary switches (one for each lane). The drum can be indexed by either a timer, or by an event such as a discrete input.

I'm not familliar with AB so I don't know what they exactly call it but AutomationDirect calls it a Drum Counter.

Click to expand...

so basically an electronic cam?


Fred Raud

Re: things to think about

jdbrandt said:

First of all, the things you are trying to describe are called air slides in the cement industry. They can also be installed inside
silo bottoms, in which case they are called air-merge slides.

As far as control is concerned, you need to consider lining up
the downstream equipment, and follow with introduction of material.
When complete, the opposite is true, with time between each shutoff,
to empty the path completly.

For instance:
Start blower
Start rotary feeder
Start table air slide
Start air slide
Open silo air merge
Open silo bottom valve
<transfer material, wait for 'full' or stop signal>
Close silo bottom and wait
Close silo air merge and wait
stop air slide and wait
etc.

Don't forget your dust collector on the top of the silo.

Click to expand...

actually,,i think they are called air slides on our silo's also,,i just started calling them airhockey's the other day being thats our "plant name" for them,, but that will now change,,

my list of events is very similiar to what you listed,,right now everything is conntrolled by mechanical timers,,relays and starters,,this will actually be my companies first attempt at moving towards automation,,,

Fred Raud

Yes exactly. To further the concept. take a TP or paper towel tube and draw a line partway around the curcumfrence. Then rotate the tube. when you can see the line the switch is on, and when you cant see the line the switch is off. Now figure you can have many lines and many switches on the same tube. Now you can set up patterns to turn on and off the switches in any sequence. Kinda like a slot machine, but all on one fixed tube. You can index the tube by one position at a time by using a sigle input to increment the counter, OR you can index the tube/counter buy rotating once with in a fixed time range. Great for x-mas light displays etc..

So if you dont have a drum instruction, you can roll your own buy using a simple counter that will close and or open comparitave contacts to start your timers. Or you can use a timer, and refernce the timer accumulator in the same way (compare the current time value)to turn on and off the outputs. (motor, blower, valves etc..)

I've got three little kids crawing all over me and my desk right now, but later I might get a chance to do a drawing and post it.

Regards, Mike

Re: Re: things to think about

Fred Raud said:

right now everything is conntrolled by mechanical timers,,relays and starters,,
Fred Raud

Click to expand...

Fred, take a close look at the existing controller drawing. You might be able to replecate it in your PLC. could be a real time saver..