Closed loop vacuüm controller

[marco32]

Posted on June 22, 2004 at 13:11

Closed loop vacuüm controller

[marco32]

Posted on May 17, 2011 at 10:17

I've not so many experience with motor control.

What is the best method for a closed loop vacuüm control. I use a 24V DC motor. Moppie

[gaetano]

Posted on May 17, 2011 at 10:17

Hi,

please, may you specify the kind of motor for this purpose, because I am not an expert with such an application. Regards, tanio

[marco32]

Posted on May 17, 2011 at 10:17

We used a kind of bottle to build up a vacuüm.

The bottle has a very small leakage (Not on purpose) The vacuüm must be hold steady. It is build up by a DC vacuüm pump which controled by PWM. It can't be controlled with a PID algortime, because by overshoot the vacuüm would stay to high. Now i've made a simple kind On/Of control, but i think there would be a nicer and better way?! also, the pump has too much problems if is controlled with 10% PWM, and there is a high vacuüm in the bottle. The pump holds. anybody?

[gaetano]

Posted on May 17, 2011 at 10:17

Moppie,

I read your answer and, frankly speaking, at distance without the system in front of me, it is hard to give you the right suggestions. You have not specified nothing about your driver system (are you using an MCU to generate the PWM and implementing your controller?) but, often, acting on the PID parameters you can reduce the overshoot as you want and at the same time could limit the minimum duty cycle to avoid any blocking conditions. All the aspects I mentioned above are relatively ease to implement when using a microcontroller, where it is very simple by acting on the firmware to change the PID parameters and the minimum allowed duty cycle. Best regards, Tanio

[marco32]

Posted on May 17, 2011 at 10:17

I'm using the ST72C254G with PWM and the firmware for the motor control.

Where can i find good documentation and application notes for PID. I've never used it before. Thanks for you're replies[ This message was edited by: Moppie on 21-06-2004 10:25 ]

[marco32]

Posted on May 17, 2011 at 10:17

Thanks Tanio.

[gaetano]

Posted on May 17, 2011 at 10:17

Moppie,

there is a plenty of documents ''under construction'' related to PID controller. They will come very soon and will be published as AN. In the meanwhile, I am trying to retrieve something to forward to you immediately. Please, wait a bit for it. Regards, Tanio

[gaetano]

Posted on May 17, 2011 at 10:17

Hello,

as promised, let's start with this document (see attached). Very soon (weeks) some other documents/ANs will follow. Please, let me know for any further need. Regards, Tanio