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Taipan
01-13-2006, 01:21 PM
Hi,

I have 2 of these motor controllers, www.ipcautomation.com/910-3522-008.html (http://www.ipcautomation.com/910-3522-008.html) that I want to control with a BS2.

To control the on/off a simple switch is used. It needs to handle 24VDC 3A. I guess I would need some sort of relay that the BS2 can switch. Can someone recommend something?

To control forward and reverse speed on these controllers a 5K Pot is used. This pot must also be capable of carrying 3A of 24V current. I want the stamp to be able to control the pot, but I have no idea how I would go about this. Any advice you can give me would be appreciated.

Thanks in advance.

PJ Allen
01-13-2006, 11:12 PM
I tried to find some information on the "throttle" potentiometer.· I looked on the site but it doesn't look like they sell/recommend one.· If you had one, then you could use·a STAMP to control it by linking it to a servo or a stepper motor (just a suggestion).·

The info at the link you provided states that the POTs travel is over a range of 12-degrees, and uses a spring-loaded sort.· A servo (standard) would always return to position zero (like a spring would.)

As far as interfacing relays -- have a look around the downloads section at www.parallax.com (http://www.parallax.com), you'll find plenty.· Also, try searching this site for "relay" and "relays"; it's an often discussed topic here.

http://forums.parallax.com/attachment.php?attachmentid=39565


Post Edited (PJ Allen) : 1/13/2006 4:18:09 PM GMT

JKtech
01-13-2006, 11:46 PM
I will put in my 2 cents worth. You might find out what voltage is across pins PL and PH. If it uses a low voltage like 10 volts you might get away with using a D to A converter and go directly in without a pot at all. This is assuming that they are using voltage not current for a speed reference.

You might also want to put an e-stop switch connected directly to the drive so you can disable the drive if something unexpected happen and the stamp, program or relay will not turn off the drive.

Bruce Bates
01-14-2006, 12:18 AM
Gents -

I'm only sorry that Taipan didn't ask on this forum about higher amperage motor controllers for wheelchairs, golf carts, or large robotics platforms prior to purchasing the motor controlllers that he apparently did. I have had EXCEEDING good performance, utility, and flexibility with another "brand" of motor controller which offers direct control by any of the following: 4-gate joystick, R/C radio control, or by direct microcontroller interface for speed and direction. Here is a link to the home page of Diverse Electronic Services:
http://divelec.tripod.com/index.html

In fact, I have a number of spares leftover from prior customer orders which I've NEVER needed to use for repair or replacement, if anyone is interested in trying one. Mine are older units with 12 volt DC, 35 ampere capacity which are no longer offered; thus the reason for my keeping on-hand spares. I would only ask a small, fully refundable deposit before shipping, just to ensure their return. That's how much I believe in both the product, and the customer support by the provider, Diverse Electronic Services, and my friend Carl Kollar. Carl devised this line of simple, but durable, worthwhile motor control products himself, and stands behind them 100%. His products, and policies are very much in tune with what we've all come to expect from Parallax. Please contact me OFFLIST if you are interested.

In addition to that, Carl also offers a very nice, and professionally constructed throttle "return and self-centering mechanism" for making your own high quality, hand operated speed controls. Commercial duty joysticks which are self-centering, are relatively easy to find, but finding a commercial duty, self-centering throttle mechanism can be most difficult. Here are some pictures, and the price of that unit:
http://divelec.tripod.com/html/throttle_pots.html

I can generally answer simple questions about these units, but contact Carl (via his web site) for anything more complex. When Carl had more time available to him, he was a regular member here on the Parallax PBASIC Stamp Forum. Complete documentation on all of his products is available right on that web site.

Regards,

Bruce Bates
bvbates at comcast dot net
(reconstruct before use)

Taipan
01-14-2006, 04:20 AM
Bruce,

Definitely sounds like the motor controllers you have would be better suited for my application than the IPC ones I have now. I bought these about 6 years ago, and I don't think I paid full price for them, pretty sure they were from another hobbyist who didn't need them any more. 12 Volt controllers would be better for me, and the MC-7 controllers look excellent, but I don't want to spend any more money than I have to on this project.

I had thought about using a servo motor on the pot, but I was hoping to work out a more direct control method. Some sort of D/A converter sounds like it's the way to go.

Bruce Bates
01-14-2006, 05:17 AM
Taipan -

If you were to use the MC-7 here is the schematic for direct digital control from a Stamp BS-2:
http://divelec.tripod.com/html/digital_control_connection_dia.html

It doesn't get much simpler than that.

Regards,

Bruce Bates

Taipan
01-14-2006, 12:06 PM
JKtech said...
I will put in my 2 cents worth. You might find out what voltage is across pins PL and PH. If it uses a low voltage like 10 volts you might get away with using a D to A converter and go directly in without a pot at all. This is assuming that they are using voltage not current for a speed reference.

You might also want to put an e-stop switch connected directly to the drive so you can disable the drive if something unexpected happen and the stamp, program or relay will not turn off the drive.


I haven't got all the gear to test it out yet, but I was wondering, even if the voltage across PL and PH was 24V, would something like this suit? www.analog.com/en/prod/0,,761_797_AD5290%2C00.html (http://www.analog.com/en/prod/0,,761_797_AD5290%2C00.html) It says it has a 30V voltage range. I am a bit out of my league here, I really should learn what all the specs mean.

JKtech
01-14-2006, 09:06 PM
Taipan

If I was you I would give them a call and ask them what the voltage is across the PL, PH pins and what they use for an Speed reference on Pin PW. I believe they have an 800 number in the documentation on their web site. The chip you are looking at wasn't exactly what I was thinking but it might work better. If the drive is using a plus and negative voltage for a speed reference that chip might be the one to use. One thing that I see that may or may not be a problem is the step change going to 10K instead of 5k resistance. Maybe if I have time I will look at it closer or someone else will have some input.

Good Luck

Taipan
01-15-2006, 03:54 AM
JKtech said...
Taipan

If I was you I would give them a call and ask them what the voltage is across the PL, PH pins and what they use for an Speed reference on Pin PW. I believe they have an 800 number in the documentation on their web site.



I am in Australia, so unfortunately the 800 number is no good to me. I have emailed them, hopefully I will get a reply. Thanks for your help.