Which Centroid controller for Bridgeport Interact?

[SimonP]

My encoders are Heidenhain ERO 115 125,
ID NR. 217 900 04.
I'm struggling to find any info on what type of encoders they are and what PPR they are.

[WesM]

My encoders are Heidenhain ERO 115 125,
ID NR. 217 900 04.
I'm struggling to find any info on what type of encoders they are and what PPR they are.

I found this on another forum, hopefully it helps

I have ERO-115-200 encoders on my CNC with sem dc motors that were supplied from Bridgeport circa 1989. i've been trying to get them to work with a galil motion card for about a month now. i can verify now, without question that this was a proprietary encoder made by heindenhain. its an 'analogue' sinusoidal output with an output in the .5v amplitude range. galil does make a board to use this signal but it will only work with select motion cards. the story i got was heindenhain supplied the encoders for sem to install, then they were sent to Bridgeport for use on their tnc series controlled bridgeports..
also the encoders were incorporated into the rear armature of the motors making a replacement encoder a custom deal.
my solution was to sell off the old motors/encoders...

Definitely sounds like you will at very least have to replace those encoders to work with a centroid control.

[cnckeith]

fyi.. typical old dc servo motor encoder replacement process.
https://www.centroidcnc.com/sem_dc_serv ... rofit.html

[jebronson]

I have updated a Bridgeport Interact. I kept the original motors and installed new encoders from Centroid. Some machining is required, but it wasn't that hard. I used the AllinOne control with Win 10 and this system is working great. I can send pictures of everything I did if you would like. Also, the SEM motors used on the Interact are a bit different than on the EZ Trac, so the video may not help. I have done both styles.

You do not want to keep the Heidenhain encoders as the line number is something like 300 which is way to low for the Centroid.

Jim B

[SimonP]

Hi Jim and thanks for all the replies..
I would like to see some pictures of your conversion if possible?

[WesM]

Some really great and informative replies there, thanks very much!
The thing that started me thinking about alternative servo motors was the need to change out the encoders on all three motors for 2000 line to suit the Centroid requirements. I took the Z axis motor apart to see what size shaft the new encoder would need to fit on and it's 10mm, the motors are SEM MT30 R4-58 and as I understand it, the original encoders aren't high enough resolution. If I keep the DC motors, there is a definite benefit from not having to machine new mounts etc., but would be able to if needed and I went for new AC servos.. interesting comment about the Chinese AC servos not being great quality and challenges in tuning them .

Please keep the comments coming, I welcome your opinions!

I'm near sunny Bournemouth on the south coast..

While a lot of people have had success with DMM tech servos, I would probably go for delta B2 servos instead. 750w B2 and B3 servo/drive kits (comes with motor and encoder cables) can be had for about $500 per axis and are used in industrial machinery. A Trak bed mill my company is looking at for their optics lab uses Delta B2 servos and a Blanchard grinder they are looking at uses Delta A2 servos.

I spoke with several machine builders when considering what to do with my machine, all of them advised ditching the DC servos. their thoughts were that integration/tuning would be a pain for people experienced with tuning DC servos and borderline impossible for someone with no experience or training. Also (Unless things have changed since I looked a year ago) decent quality encoders cost $200+ and would pail in comparison to the 17 to 24 bit encoders that come stock on most AC servos. At $200+ you are almost halfway towards more capable modern AC servos.

[jebronson]

Hi SimonP, Sorry I didn't get back sooner, must not have the notifications set right.

Tuning on the DC motors with Centroid was not a problem. Unless you are going to use the machine 10 hours a day every day, the DC motors will last.
Where I work, we have machines 20 years old running every day with no problems.

I will post the pictures as soon as I resize them.

Jim B

[jebronson]

Pictures,

[jebronson]

Attached are some of the motor pictures. PM me if you would like the full set and size.

I used an encoder available from Centroid. The motor and encoder cables as well as the junction box adapter are from Centroid as well.

[SimonP]

Apologies for the delay in replying..
Appreciate the replies and comments.
Thanks for posting the pictures, nice job..!
I've had to park this project for a while as other things have taken priority, but I am leaning towards replacing the DC motors with modern AC servo motors. As was said previously, the cost of the encoders goes quite a way towards the cost of new AC servos and opens up options on controller boards, either Acorn or Acorn 6 etc..
I will report back once I am back on it..