Need some Help!!!

[kamenges]

If you really need to define your profile in terms of time like you have shown in the figure you posted, I would use Allen's method. I have done something similar in cases where I needed a true time-based ramp (the ramp takes the same amount of time regardless of the size of the change).
If all you are really concerned about is the time of the changes you can use theb Motion Axis Jog command (MAJ). You can use the timer structure that Allen shows to determine when to change speeds. Then just move a new desired jog speed into the instruction whenever you need to change speed.
You can do time based accels with the MAJ instruction also but you would need to divide your change by the amount of time you want it to take and use that as the accel rate.
The only thing the MAJ instruction brings you that Allen's method doesn't is S-curve accelerations.

Keith

 

[Patson]

Need informations

Thanks Allen for your answer but I don't really know how to insert or this pogramm on controllogix(Rslogix5000) and make it run,i means see the curve.You said it easy to do that, but i have no idea how.

Thanks for your help.

 

[Patson]

HI

I just want to know how to ingrate MAJ(Motion Axis Jog ) on ALLen code, thanks allen for your code.

Thank you everybody for your help, i begin to understand and like this domain(PLC).

 

[kamenges]

Patson-
It looks like we might have multiple problems here.
It looks to me like you don't have the necessary experience to enter instructions in a Logix5000 program. Unfortunately this is not a good place to learn that. You need someone closer to you to help with that or you just need to do it. Allen's code is directly convertable to the ControlLogix platform. He intentionally entered it without addresses so it would be. If you have trouble entering Allen's rungs you will have just as much trouble loading different values into the MAJ instruction to get it to do what you want. You need to get comfortable with entering instructions before you tackle the concept of ramp generation.
Try to enter Allen's code just as you see it. Then let us know what specific probelms ytou run into. And PLEASE post them on the general forum. You will get infinitely better response, especially for the rest of this week.

Keith

 

[Patson]

No problem

I don't have problem with Allen Code , I already apply it, but i can test it because of lack of PLC, perhaps tomorrow, I never did PLC programmation , but I'm very happy for all I learned here,you are very smat, and thank you for all your advices,after i will take an course on it and i will be better.
So I just ask Keith how to integrate MAJ.
I already make taste with MATC, MAJ ,but just how to integrate it with Allen's code.
Sorry for all my questions, I'm begginner on PLC.

 

[kamenges]

If you can use trapaziodal velocity profiles the MAJ instruction won't do you much good. You will still need all of Allen's code except the compute instruction at the very bottom. The MAJ would take the place of the compute.
I suggest just sticking with Allen's code and modifying it to suit your needs.

Keith

 

[Patson]

Many difficulties

I tried to integrate Allen's code to my application, but i have many problem to generate the ramp i want ,just see the modification I made to this code and result and please tell me what's going on,otherwise i will abandon it.

 

[kamenges]

Patson-
Good effort. However, there are a couple of points you need to look at.
First of all, it looks like you saw somew things you didn't like and started modifying Allen's code. That's good to see; it shows initiative. But you may have hurt yourself with a couple of them. In Rung 1 you force all of your frequency values directly to zero, including the output frequency, which you want to ramp. So you need to get rid of that.
Another thing you noticed is that Allen's example assumed you wanted the whole cycle to complete on it's own once it started. That's the way your original bitmap seemed to state the problem. It looks more like you want to go through all the ramp moves except the one back to zero and wait to go to zero until you turn off the run. It looks like you tried to account for this in rung 11. Instead of using a TON for T6 use a TOF, an off delay timer. This will make your ramp to stop begin when you lose the start input.
Another important point is that ANY TIME you move something into FINAL_FREQ and INIT_FREQ you need to use a oneshot. These points are intended to be start and end points. They are set at the beginning of the ramp cycle and shouldn't be modified after that.
Now, in your defense, Allen does have a couple of typo's. In rung 12 you don't want to use the T4 values. You want to use the T6 values as T6 defines your final ramp.
You can't lead the CPT instruction with that start contact or you won't calculate your final ramp. So make the CPT unconditional. Maybe your rung 1 wasn't such a bad idea. Just use the normally closed of T6.DN instead.
Take another swing at this and let us know how you do.

Keith

 

[Patson]

Thanks

I will work on it and let you know how I advance.