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Laboratory multi channel peristaltic pump controller — Parallax Forums

Laboratory multi channel peristaltic pump controller

DarrylBorlandDarrylBorland Posts: 3
in General Discussion
Hi I`m new to Parallax forums so here goes.

I have some old laboratory grade peristaltic pumps that I wish to convert to computer control. Basically I need to drive the pump motor forward, backward and stop and vary the speed. I was thinking of using the HB-25 controller #29144. But would like to use USB to talk to the microcontroller.

Any ideas or direction would be great.

Thanks

Darryl

Comments

  • RS_JimRS_Jim Posts: 1,765
    Hi Darryl,
    Welcome to the forum. Some info about the pumps would be useful, like what voltage do they require and how much current do they draw. The HB25 may be an expensive way to go.
    Jim
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2015-11-18 15:31
    The HB-25 is a good product and may outlive many projects with different uses. So I wouldn't dismiss it outright. Much depends on the motors you choose to drive.

    As far as using a USB interface, a Propeller board can provide you with that. And Forth on the Propeller would interactively help you to quickly dial in whatever you desire those pumps to do. With the Propeller, it would be easy to have multiple pumps responding to independent pump cycles.
  • jonesjones Posts: 281
    Without more info, it's hard to offer much help, but you may be able to use the motor control circuitry built into the pumps if it still works. As an example, I once had to modify an old but high-quality circulating water bath for computer control. Instead of controlling the heater and chiller directly, I was able to use a computer to generate an analog voltage that replaced the manual temperature control potentiometer in the water bath control circuit. To heat or cool the test chamber, I just made a small adjustment to the set point temperature with the computer and let the built-in controller deal with the high power needs of the heater and chiller. In that case I had to add external temperature measurement capability for closed-loop control, but with a peristaltic pump you may not need a closed loop.
  • DarrylBorlandDarrylBorland Posts: 3
    Ok I will post a picture of the unit once I get back to the other lab. These are 220Volt pumps that draw a few amps. Which made me decide on the HB25. We have someone here who can make the GUI no problem. Do we need to use Parallax exclusively. I ask because this person has alread created a USB interface to talk directly to some dissolution baths and spectrometers. We would like to keep with the same look and not have a separate, different looking interface just for the pumps.

  • Hal AlbachHal Albach Posts: 747
    edited 2015-11-19 14:16
    The HB-25 has a load rating of continuous 25A @ 13.8 Volts DC, which is far below the 220 Volt pumps you have indicated. Specs for HB-25 indicate a maximum motor voltage of 16 Volts DC.
    Is that 220 volts DC?
  • kwinnkwinn Posts: 8,697
    The type (AC, DC, synchronous, stepper, servo, etc) of motor and it's operating voltage determines the type of controller needed to drive it. You need to find and post that information to get more specific help with this project. If there is a make and model sticker on the pump you may be able to find the information on the internet. If you post it someone on the forum may be familiar with it.
  • DarrylBorlandDarrylBorland Posts: 3
    I will get you guys all the specs tomorrow morning. Its 430pm here so I have to wrap up things up. But if can tell me if it`s possible to write our own GUI or are we stuck with parallax stuff. Would be nice to talk directly to the H bridge via USB but that is not possible. So the propeller might work as long as the interface can be written by us to maintain the same look. What we did here with the other machines was talk directly to the RS232 port via USB adaptor. Boss wrote the code and made the GUI this was done before my time and I know it was a pain the neck to decipher. But it work well and I want to do the same with this silly pumps.

    Thanks again,

    Darryl
  • kwinnkwinn Posts: 8,697
    The propeller can receive serial data, so it can receive commands from a USB to serial adapter and software running on the propeller can execute them. That kind of application is a fairly common task for the propeller.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2015-11-20 06:55
    First off, determine if that is 220VAC or VDC.

    Since you want to drive forward, backward, stop, start, and vary speed; all the specifics of the motors are extremely important. And you may find that the motors you have won't reverse or vary speed. AC motors will require a very different solution than DC motors, and there are various types of AC motors.

    If that is the case, you may have to consider a change over to a different set of motors. You might also require quadriture encoder sensors attached to the motors for precise feedback to allow PID motor control.

    Do you have any ballpark power rating on these motors such at 1/10th HP, 1/4 HP or such?
    Given 'a few amps at 220V' where amps times volts equals watts, you seem to have something like a 500 watt motor. With 745 watts per horsepower, you are indicating 2/3 HP motors or larger.

    There may be an industrial servo controller that is already well suited for these devices. Whatever you do decide to use, should have a proven performance record for such large motors. I fear it won't be cheap.
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