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lonely88 June 20th, 2016 02:00 AM

delay starting of 7 motors
i am new to this field of plc programing i got an intresting program which i cant crack.i will be very happy if someone could help.

i have 7 motors,when the user activates any first motor of the sevens no matter which one it starts right away.if the user start any more than one motor there will be delay of 5 seconds between every motor start.
the system most remember the starting sequense that was asked.

i only can use ladder for that project.any ideas how to solve this problem?

shooter June 20th, 2016 03:43 AM

whenever a motor is started, disable the inputs for 5 seconds, to prevent starting a motor.

for the sequence you will need an array, if a motor is started and the array[0] is 0 then array[0] is number of motor) if array is filled add index and try again.
you will need a few more buttons to autostart sequence, and to erase sequence, apart from the stop button.

lonely88 June 20th, 2016 09:05 AM

and if i dont have any other buttons and i wanna do it?
is there any way?

lonely88 June 20th, 2016 09:35 AM

my main problem is creating the array with the ladder i created something using memory bit but i can get it to do a loop and scan each time which motor needs to work now.

Doug-P June 20th, 2016 09:40 AM

A thousand miles can be so many ways. Just to know who is driving, what a help it would be.

Which PLC is being used?

lonely88 June 20th, 2016 10:41 AM

I am using easy 806 by eaton using smartwire.

nhatsen June 20th, 2016 01:30 PM


Originally Posted by lonely88 (Post 696233)
... the system most remember the starting sequense that was asked.

How and when do you set the starting sequence?

lonely88 June 20th, 2016 01:46 PM

The buttons pushed by the user on start of the work day the sequence only matter for the engine start so there will be no more than one engine starting so there will be no waytwo engines starting at once.

Pete.S. June 20th, 2016 02:04 PM

You need one timer for each motor, an on-delay.
We'll call the timers for the motors, on_delay1, on_delay2 etc.

Then you need one timer that counts down to zero. It doesn't control anything with it's output, it's just to keep track of time.
We'll call that down_counter.

You'll manipulate the start of the motors by manipulating the delay times on the on-delay timers.

Example user wants to start motor 4.
You take the actual value of the down_counter and put it in on_delay4.
You then add 5 seconds to the down_counter.

For the first motor down_counter will have counted down to zero. So the on_delay will be set to zero, which will make the motor start immediately.

The down_counter counts down 5,4,3..and then the users starts another motor, say motor 7. We do the same thing.
Down_counter is 3 so on_delay7 is set to 3. We add 5 to down_counter and get 3+5=8.

Let's say the user immediately starts motor 1 as well.
We do the same thing.
Down_counter is 8 so on_delay1 is set to 8. We add 5 to down_counter and get 8+5=13.

And so on and so forth....

Write it down in a spreadsheet so you'll understand how it works and what happens as time passes by.

It will also work perfectly if one motor is stopped and then restarted again while others are also starting up.

Easy to expand as well since it's not depending on how many motors you have.

And the motors will automatically start in the order they triggered by the operator.

If you have some motor that is bigger and you want to delay other motors for more than 5 seconds you just add more than 5 seconds to the down_timer when that motor is started.


Doug-P June 20th, 2016 02:13 PM

Never used this device but it looks like the TABLE function would suit your purpose.

lonely88 June 20th, 2016 03:01 PM

i never worked with tables so i dont really get how they work i though of using one of them but i didnt found any good tutoral on how to use it..

gclshortt June 20th, 2016 04:17 PM

1 Attachment(s)
I would follow what Pete.S. said to do with the program. It would be easy to implement.
I tried it out with the Do-More Simulator and it works well.


Pete.S. June 20th, 2016 05:10 PM

Great work Garry!

I never tried the Do-More simulator.

Is it part of the free Do-More programming software?

Would it be possible for you to post the project you just made (attached zip file) so I can play with it?


twocozz June 21st, 2016 07:55 AM

Well I have done this lots of times but I must say the solution from Pete.S knocks mine out of the water. So simple, so elegant - just love it - cheers

gclshortt June 21st, 2016 08:59 AM

1 Attachment(s)
Hi Pete,
Yes, this is the free Do-More Designer Software.

Attached is the program as requested.
You will notice that this has been modified because if the motors are all on and the power to the PLC is disrupted, the outputs will all be switched on again at the same time.
This will also happen if the PLC is stitched from Stop to Run mode.

If this happens the motors will turn on in number sequence if there switch is on, at 5 second intervals.


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