Building a 5 Wire Servo Controller

AI Thread Summary
The discussion centers around building a controller for a 5-wire servo, with the user seeking clarification on the function of each wire. It is suggested that the servo may not be a stepper motor, as it exhibits characteristics typical of servos, such as resistance when turned and sound feedback. The user expresses frustration over the lack of information available online and considers the possibility of a proprietary interface due to the missing controller for their xyz stage. Another participant shares insights about 5-wire synchro-resolvers, detailing their wiring and function. The conversation highlights the complexities of understanding and controlling these types of motors.
seang
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Hi,

I am supposed to build a controller for a 5 wire servo. I'm having trouble finding information online that appeals to electrical engineering folks.

What are the 5 wires? I suspect there is power and ground, but that leaves 3 unknown connections :eek:

I have a basic understanding of servomotors (though, by no means complete), to the point where I can get a handle on the application circuit in the following datasheet:

http://www.datasheetcatalog.org/datasheet/MitsubishiElectricCorporation/mXyyzzzr.pdf

Maybe someone can help me understand what the 5 connections are in terms of the above circuit? Do you think it would be possible to make a basic controller with a PIC uC?

I know this post is kinda vague, so thanks for any thoughts or help.
 
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The five wire motor is a stepper motor. It's composed of a number of electromagnets that have to be activated in sequence to rotate the shaft. And you need a special driver for that too.

http://en.wikipedia.org/wiki/Stepper_motor
 
Hmm, I don't think it's a stepper. From my experience, you can usually turn a stepper in your hand without much physical resistance. You don't get that dynamo charging sound like you do when you turn a servo. (I get the servo sound, on this one.)
 
seang said:
Hmm, I don't think it's a stepper. From my experience, you can usually turn a stepper in your hand without much physical resistance. You don't get that dynamo charging sound like you do when you turn a servo. (I get the servo sound, on this one.)

Never mind, forgot some servo motors have error correction for a feedback loop.
 
I think I might give up on this one. The servos are part of an xyz stage, which is supposed to come with a controller (both the stage and controller are made by the same company). Well, the controller has been missing for many years.

My thought is that the interface is somewhat proprietary; they probably don't want you to figure this one out ;). Thoughts on this?
 
The 5-wire synchro-resolvers ("servos") I have used had two wires for ac power and return, and the other three wires transmitted/received a 3-phase angular position signal to/from the other synchro. Either synchro could be used as a sender, and the other as a sender. We would put a hand crank on one and the other synchro would follow. I have never used more than two connected together.

Edit: These units were also called selsyns. See Figure 2 in this for wiring diagram:
http://www.navweaps.com/index_tech/tech-051.htm
 
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