Stepper with 200 cpr encoder

[mdoan]

Anyone used the Tamagawa brand steppers, TS 3643 NI, 282 oz/in, 2.2v/4.6amp, with built in encoder?

I'm investigating parts for a cnc retro of mini-mill (Homier). My second question is, what use are the encoders for microstepping if they only register 200cps?

Thanks all.

[buscht]

I am using them. They are great! The encoder is unused in my application. I just bought them because the price was right.

[mdoan]

Thanks B. I'll try them out. I still need to figure out what to do with the encoders.

[jrc347]

I bought a set of those steppers off of ebay a while ago. ecellent steppers, but the encoders are basically useless on a stepper motor. my encoders were only wired for the 1 ppr index. i took the encoder apart and wired in the A and B sides so i could get the 200 ppr. i use the encoder only on the z axis as a sort of dro (i use mach 1 for running the machine). hope this info helps

[HuFlungDung]

Originally Posted by jrc347 I bought a set of those steppers off of ebay a while ago. ecellent steppers, but the encoders are basically useless on a stepper motor. ~snip~

How about the stepper motors are basically useless on an encoder?

Sorry, guys, I'm a servomotor man

[mdoan]

Thanks for the info. I guess they will make due as the DRO inputs.... albiet lame duck when microstepping.

[jrc347]

Huflung, the way it was explained to me was that when the stepper stalls, there is no way to bring it back to the correct position by adding more current to the motor. Also mach 1 will not recognize the encoder as a feedback signal for closed loop operation. Ex. If the stepper motor stalls while making a deep cut, then no amount of correction can make it overcome the force that made it stall.

Well i know that is probably confusing as hell, i hope someone else can clarify.



Disregard all that stuff above, I just reread huflung's post again and his meaning finally sank in

[ger21]

Originally Posted by mdoan Thanks for the info. I guess they will make due as the DRO inputs.... albiet lame duck when microstepping.

Unless you want to buy a complete proprietary system (including software) for a LOT of money, you won't need encoders on your steppers.

And, I seriously doubt you'd need them for DRO's. If you're using Mach2, for example, you'll have DRO's on the screen which display the motors position (supposedly). If you had another DRO with input from an encoder, You'd have to compare the 2 while they are constantly changing to try to determine the difference, if there is any. Impossible, imo. The only time you would know if you had lost steps would be after the cutting was done, and by then it would be too late.

Having said that, Art has recently said that he is working on a closed loop TYPE system for steppers for Mach3, and Mariss (from Gecko) has an idea for a system using his G2002. So you never know what might be available around the corner. But the bottom line is, virtually no one uses encoders on their steppers.