Driving motorized valves

Help & Support Robot Parts
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I’ve got a work project where I have to control four small motorized valves. The motors are 6-12V brushed motors and each max out at 185mA. I’ve got a National Instruments DAQ system to work from, but the valves got selected late in the design process and I’m running out of digital channels to operate them. I do have some analog output channels that I could use, and I would actually prefer if I could get speed and direction control out of those. The system is incredibly complex, and I really want to avoid any tricks that complicate the software any more than necessary.

The process is to run these four valves in parallel for maximum flow, and as my flow needs decrease, I close one at a time until the very end I’m “feathering” the last valve, and I need independant control of each motor. For the immediate future, the control feedback loop will be manual, but once we get a good handle on their performance, we hope to automate the process. The motors have no feedback provisions; we have to use other system diagnostics to tell us what the valves are doing. The valves I’ve selected are far from the ideal, but the requirements are strange, and I haven’t been able to find something better.

Robotshop has the best selection that I’ve been able to find for motor controllers, but I’m having a hard time confirming that the controller manuals and I understand the terms the same way. A billion years ago my hobby was robotics (long before the internet, too) but the technology has changed a lot since then.

Thanks to all, and as my first post, I apologize for the lack of real introduction, but this is a challenge I need to solve quickly.
Quick intro:
(Hi, my name’s CarlMc, and I’m a geek…)
I grew up spending my meager money on Radio Electronics magazines, dreaming of building the robots featured there in, and learning electronics from my databooks… A real computer got hooked up to your TV, and interfacing them to the real world was via parallel port and nothing else. Am I dating myself? I then made electronics my job, and all of a sudden I realized it wasn’t my hobby anymore. Dangit!

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Thanks for the response, Casmat!
It’s the analog into the same pin as PWM that had me slightly confused. Most of the documentation isn’t very clear on that, and I’ve been burned more times than I care to recall with these little issues. I was looking at the Cytron RB-Cyt-20, which I think is fairly generic in that sense, but I’ll take another look at the one you mentioned.

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Hi CarlMC, nice to met you!

You could use a quad-DC motor controller to drive your valves such as this one: RB-Lin-35

Almost any controller in this section will do: robotshop.com/low-power-motor-controllers.html

If you decide to control them with a PWM signal, then you will need one PWM pin per valve and one digital pin to set the direction. You could also opt to use analogue motor controller in which case you will set the speed using an analogue voltage (from 0 to 5V usually)