JR ES 579 servo pin out

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BrendanP

Senior Member
I've got a JR ES 579 servo.

It has red, brown and orange leads comming out of it. I presume red and brown are ground and +6V and that orange is connected to the picaxe. Is this correct?

I have it conected up like this and its giving very jerky opperation. I have it running on a seperate power supply as indicated in the manual. I thouight I better get advice in case I damage it.

Are servos availiable that give a analogue signal out indicating the amount of current they're drawing?
 
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BeanieBots

Moderator
I can't comment about that specific servo but the wire colours are common to many makes and are as you describe. It would not work at all if it was wired wrong.

It will be 'jerky' if you are making frequent updates to the command.
Avoid updating more than every 20mS.

I am not aware of any 'hobby' servos that give a current signal.
Most 'industrial' servos will have such a signal but they usually require voltage or current signal demand and therefore would not be compatable with the PICAXE servo command.
 
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BeanieBots

Moderator
It's not so much which brand but the servo you pick from that brand.
It's a bit like buying a car, so many makes and models to choose from.
I've always found Hitech and Futaba to be very reliable but make sure you choose the right one for the job. Speed, torgue and bearing choice are probably the most important choices to make.
 
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BrendanP

Senior Member
Yes, I did tie the grounds together, but the thing opperates albeit badly rather whether I have the ground tied together or apart. The picaxe is running off batteries, 4.5V, the servo is running off my bench top power supply, 6 volts.

Ive had the thing going well in the past, serves me right for not making notes. I need to have a notebook for each project that I can then go back and review when setting things up again. I have a few projects on the go and I don't have bench space to leave everything set up at once.
 
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flyingnunrt

Senior Member
As already stated servos come in all guises, the cheapest have no bearings
the next level up are ball raced then there are coresless motors and then digital versions and so on, there are big ones and little ones, high torque and high speed, the list is long.
JR Futaba Multiplex Hitech are all pretty good but you can get some fairly cheap "no brand" ones on the internet. Most of the "good ones" will have better resolution and speed than the picaxe is capable of delivering.
Static current may be 100ma but insantaneous current could be around 1000mA give or take a bit. Your benchtop power supply might be limiting? Try some nicads.
Put an analogue ammeter in either pos or neg leads to observe the current draw when operating.
 
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Wrenow

Senior Member
For the most part, I would make sure you have a common ground and stable power supplies (I would go batteries to start). Yes, with that servo, brown and red are ground and positive, orange is signal. Many servos are, at most, 6v tolerant, and are designed for 4.8v, so keep that in mind as well. The timing and update rate are critical - you do not want to change the servo command more than once every 20ms.

As for types that are good, hobby servos have become pretty much commodity items, all the major brands are fine, Futaba, Hitech, Airtronics, JR, even GWS, Bluebird, Dymond Modelsports. I have had good luck with all of them. Some, like FMA Direct have some unique features (manual programmability).

If feedback is important, you might want to go with one of the newer robotics servos like the Dynamixel series available from
http://www.crustcrawler.com/products/AXS1/index.php
or one of the Open Servo project offerings - see:http://www.openservo.com/

Keep in mind that these do not use your normal servo commands but use other TTL communication protocols that might or might not be better for your use. Caveat Emptor time - I do not have, nor have I used, either of these products, as I do not have a current need for them and have too many other projects in the works, but they do exist if they look useful to you.

Cheers,

Wreno
 
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