motor control for conveyor

[backendcode]

Hello Everyone, I am very new to PLC programming and trying to learn PLC by myself. I found this awesome forum and would like to get some advice on my project at work.

Project. I have 4 conveyors with 4 proximity sensors, 1 proximity on each conveyor. Each conveyor is controlled by an individual motor.

1. The operator will put the part(company product) on the first conveyor and will make sure put on top of the proximity sensor.
2. Before the motor1 turns on and move the part, the proximity sensor 1 will check the condition on the 2nd conveyor and see the state of proximity sensor 2 of conveyor 2. If 2nd conveyor has already part on it, conveyor 1 won't On and will not move the part to the 2nd conveyor.
3. same logic will apply to conveyor 3 and 4.

I created a program. I don't have actual PLC processor right now to test it but can someone look into the program and tell me if I did right or no.

Pic attached


Note: I respect everyone's time and not looking for someone to do this project for me. I will try to finish my project and you can correct me and advise me to do better way. Thank you

Best,
Backendcode

 

[bernie_carlton]

You are using an output in an OTE command twice. This won't work.

 

[harryting]

My eye sight aren't what it used to be so I can't make it out.

I would suggest getting the Emulate 500 and RSLogix 500 Micro edition to try your logic out:

https://www.theautomationstore.com/...-emulate-500-installing-and-configuring-them/

 

[backendcode]

You are using an output in an OTE command twice. This won't work.

Thank you for your response!

Let's talk about rung 0 (technically 1st line of PLC code)
What I am trying to do here, First time OTE (Motor1) will get on when condition is true and used latch run to keep the motor ON and then my timer will turn On for 5 sec and after 5 seconds, my done will be enabled and change the stage of my motor 1 to 0 to turn off (rung1)

Do you think I am thinking wrong logic? Can you please correct me!

Thank you

 

[backendcode]

My eye sight aren't what it used to be so I can't make it out.

I would suggest getting the Emulate 500 and RSLogix 500 Micro edition to try your logic out:

https://www.theautomationstore.com/...-emulate-500-installing-and-configuring-them/

Ok Harryting, thank you for your suggestion and I will definitely look into that.

 

[bernie_carlton]

Please describe what effect the 5 second TOF timers will provide.

 

[backendcode]

Please describe what effect the 5 second TOF timers will provide.

TOF timer will turn off the motor 1 after 5 seconds ( I guess )

 

[James Mcquade]

how long is each conveyor?
are they in line with each other, based on your statement, yes.
what is the product weight?
what is the size of each product?
is the product on pallets?

an easier solution may be to use an accumulation conveyor with zone control, but I need you to answer these questions.

james

 

[backendcode]

how long is each conveyor?
are they in line with each other, based on your statement, yes.
what is the product weight?
what is the size of each product?
is the product on pallets?

an easier solution may be to use an accumulation conveyor with zone control, but I need you to answer these questions.

james

James,
Thank you for the reply!

1. Yes, these conveyors are in series or in line and 1 worker to load the part from one end and 1 work to off load the part from another end.
2. the weight of product is around 60 pounds (Hollow metal doors)
3. size will be 30 x 80 inches
4. A door will be coming from another production line and welding guy will weld the door at the end of another production line which is perpendicular of this and he will slide the door on this line and proximity sensor will get activated.

The goal is to move the door from one conveyor to another until it reaches the last conveyor of line and worker will take the door down.

Please let me know if you would like to know more anything else and I have no idea about accumulation conveyor but I am going to look into that on the internet.

Thanks

 

[ScottTheEngineer]

TOF works by timing when the conditions on the rung are false. I think you want a TON.
When TON turns on the .TT and .EN turns on .DN turns off. They stay in this state until it times out. .TT turns off. .DN turns on .EN stays on as long as the rung condition is true.
Its really really hard to read your photo.
The way it looks currently, You put a part on CONV 1, it turns on and stays on....Forever.
Your TOF never does anything because its activated by False rung condition. Also Bernie is correct. You can put multiple OTE's in the program but only the last one scanned really matters. I got screwed up by that once. Just once though.
The rest looks like a repeat of the first.
Change TOF to TON. Get rid of motor latch and use TON.TT bit. if you want it to run for 5 seconds.
Keep working the problem.. you'll get it.

 

[OkiePC]

Is this a classroom assignment or a real world application?

The answers you give for an assignment have to accomplish the requirement of the instruction/curriculum. The answers you give for a real world application need to be more robust and think through all of the what-ifs.

What if my logic starts moving a product and then a sensor fails. Do I run the conveyors forever or for a time limit?

What if the door stops at the instant it first makes the switch and the laborer would suffer much less back strain if it traveled another X seconds before stopping?

What if debris accumulates on the conveyor and makes one or more of the sensors flicker?

Those are just the most obvious what-ifs, real world practice is likely to reveal others.

 

[James Mcquade]

What is the length of each conveyor?

james

 

[backendcode]

TOF works by timing when the conditions on the rung are false. I think you want a TON.
When TON turns on the .TT and .EN turns on .DN turns off. They stay in this state until it times out. .TT turns off. .DN turns on .EN stays on as long as the rung condition is true.
Its really really hard to read your photo.
The way it looks currently, You put a part on CONV 1, it turns on and stays on....Forever.
Your TOF never does anything because its activated by False rung condition. Also Bernie is correct. You can put multiple OTE's in the program but only the last one scanned really matters. I got screwed up by that once. Just once though.
The rest looks like a repeat of the first.
Change TOF to TON. Get rid of motor latch and use TON.TT bit. if you want it to run for 5 seconds.
Keep working the problem.. you'll get it.

ScottTheEngineer,

So what you trying to say is, if input condition on the first rung will be true, it will turn on my motor and I need to use TT parameter of TON timer to keep the motor ON and TT will set to zero when acc >or = 0 preset value and it will turn on the done (DN) bit and I can use done bit whereever I want it?
Right?

Thank you for reply!

 

[backendcode]

I just attached the PLC program link here. Please have a look if you can not see

https://ibb.co/fvaZE5

 

[backendcode]

What is the length of each conveyor?

james

10 feet!

Thanks