PID control from VFD

[powersoff]

Does anyone know of a good book or website that would explain setting up a PID on a VFD with no external controller. Mainly I work with the Altivar, Yaskawa and Allen Bradley line of drives. I have never set up a PID in any of the above brands but might need to in the near future and would like to get my feet wet before jumping in. I have tried to wade through some of the drive manuals. After reading manuals PID setup, I don't feel like I am winning (learning).

 

[waross]

A course in PID is a little beyond the scope of this forum. There are many courses and text books devoted to this subject.
If you describe your project you may get some suggestions for settings.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jraef]

I have set up countless PID loops in VFDs. I will tell you that the PID loop programming of Altivar drives is the most difficult I have ever encountered. I once used up 600 minutes of cell phone time with Schneider's tech support trying to stabilize a simple loop on an ATV71 drive; they were useless. I eventually figured it out without them when my battery died, but it was one of my worst experiences. I would NOT recommend starting there if you have never done it before.

Start with your A-B or Yaskawa drives, they are a LOT easier to understand and the manuals for them are a lot more clear. I work for Siemens and our PID loops are relatively easy to set up as well. Although they are a competitor of mine now, I have to say that the easiest PID loop setup I have ever encountered in a VFD is on the ABB ACS-550 drives. If you want to learn how it COULD work, I would recommend starting there.

But here are my suggestions:
[ul]
[li]Plan out exactly what you want to accomplish, i.e. maintaining pressure, flow, level etc., then make sure your application is valid. Most problems start with people being unrealistic about what they think it will do for them.[/li]
[li]Label all of your inputs and output associated with the PID loop exactly as the VFD manual has them set up in programming. In other words, if the Process Variable input is going to be function P2232 in programming, label your devices as such, if only temporarily. It makes things more clear when you are tuning it.[/li]
[li]Make yourself a logic flow chart that YOU can understand which labels the main functions both as the key points in a PID loop AND the program functions in the VFD. For example, PV = P2232, SP = P1011, Offset = P1234, Gain = P4567 etc. etc. Some of the VFD manufacturers do this for you, but they often use their own notation method. Others (Altivar) use non-industry standard terms, or they have been translated from another language in ways that can be confusing.[/li]
[/ul]
Good luck.

 

[Compositepro]

Here is a useful document on tuning temperature controllers.

http://www.omega.com/temperature/Z/pdf/z115-117.pdf

Once you start to understand PID controller tuning you can apply that to controlling anything.

 

[ozmosis]

Powersoff
Depending on the application, don't get too hung up on the "D" term of the PID. My business is drives in the HVAC industry and it is rare (if ever) to use the D term on the controller. However, complex performing closed loop control may need the D term but this is often with high performance drives such as servo control systems.

 

[electroment]

I hope this will help, Application of PID is for control system, such DCS which will able you to control your application. Your input PV,SP, OP or whatever appliction you used from these your drives will follow.

You may study DCS (distributive control system)control loop inorder to understand more of the application of PID.THis DCS explain better about PID. You have to set your application(flow control or pressure control etc., interlocks, your loops,inputs/outputs whether analog or digital.

You can try Yamatake PID loop systems, a little bit similar to allen bradley