MY SM1 cnc mill PC control retrofit saga.

[zook]

Hey:

I thought I would chronical the retrofit of my SM1 CNC to a PC based controller. This is my first, so any help would be appreciated.

I know i am going to have a ton of questions for the forum, so I will apologize in advance.

I have attached a pic of what I’m starting with. It is a 1984 model. I bought it from the original owner with all of the manuals and even some tapes! Other than being a little dirty on the outside (the electronics are sparkling clean) it's in pretty good shape. It even has a couple of new servos. Not a bad deal at $750 huh?

It has the BX controller but that, along with all of the original electronics is going to be sold.

Here's a current rundown of the products I have researched to use:

Hitachi X200 VFD
Bob Cambell combo board OR a CNC4PC c23
Gecko 320 drives (they work with the combo board) The servos are 80v. This is at the upper limit for the drives. Are they going to burn up? If i use the C23 board, i might look at viper drives
Since the servos are tach, I am going to need some encoders. Any suggestions?
I am probobly going to go ahead and replace the limit switches as well. Any suggestions there?
Mach3
I still need a power supply 80v 20 amps. Any suggestions? Do I need a power supply for each servo?

That's where my plan is after a few days of looking/calling around. It is not set in stone, but i would like to start buying some stuff soon. Am I making any big mistakes here? Is all of this going to work together? Any other suggestions? Am I missing any major componentry?

I'll post again when I have some news.

Thanks,

Pat

[springlakecnc]

Hitachi X200 VFD

If you didn’t buy it yet, check out Automation Directs “GS” series frequency drives, you may save a buck. I bought about 10 of them and never had any problems.

Bob Cambell combo board OR a CNC4PC c23

Get Bobs board. I haven’t looked at his instructions lately, they used to be written for an electrical engineer, BUT, It’s well engineered, meaning, I have seen a lot of questions from people about problems they have, that they wouldn’t of had if they bought Bob’s board.

Gecko 320 drives (they work with the combo board) The servos are 80v. This is at the
upper limit for the drives. Are they going to burn up? If i use the C23 board, i might look at viper drives

Either board will run either axis drive. I don’t think Gecko’s will burn up at 80 volts, unless you hook them to those Hurco motors that are way to big for that drive. Do you understand the drawing for enabling the Gecko drive? I do, and I built them, and it works funky 4 sure. Do you have an oscilloscope? Read Gecko’s manual about tuning! Did you study the limited 50ma of 5volt power for the encoder? How much do your encoders draw? If you don’t have a differential encoder, did you read how long (or short) the encoder cable maximum length should be? Do you know how important a pulls multiplier can be? Your answer is “no” to all. Get the Vipers.

Since the servos are tach, I am going to need some encoders. Any suggestions?

Try US Digital, and don’t forget to order the cables with plugs to the length you need and “do” wire up the shielding, its there for a reason. Also they have tech support people that will help you, and they seem to be very happy, even though you are only going to buy 3 encoders, vs some other companies that you have to buy 10 of the same to get a decent price. Ajaxcnc has decent encoders for reasonable also.

I am probably going to go ahead and replace the limit switches as well. Any suggestions there?

If they work, why replace them? Just clean them up. The guys that get all those false limit switch tripping probably ran logic level current through them. Bobs board has 12 volts for the limits.

Mach3

If I could only have one software, it would be Mach3 (I do have it, along with others). Be prepared to spend some time setting it up. I think Bob Campbell has a set up file for his board, for the Mach3, which could save you days. Mach3 runs in Windows XP. Remember, if you plan on mounting your computer on or in the cnc machine, the hard drive will be destroyed. All flash memory solves this problem. Dos or Linux fits on small flash drives, way easier than Windows XP. The pulls stream in Mach3 is really nice, for a charge pump. Personally, unless I’m digitizing something, I use a dos program because I’m a cad cam user, and I just download, set datum zeros, and push cycle start. The Mach3 has all your fancy stuff like engraving and canned cycles that I generate right in my cad cam.


I still need a power supply 80v 20 amps. Any suggestions? Do I need a power supply for each servo?

Keling sells power supplies. I bought a lot of stuff from them, their nice people! If your going to use those Hurco motors, don’t get under a 1,000 Volt Amp power supply (1KVA) and you only need one. And now the bad news, you need the big viper drive. If you insist on using a smaller drive, go on the Rutex web site, and read up on running a servo motor with an under sized drive! Did you look in the Hurco cabinet? Maybe you will get lucky and find a power supply in there! I retrofit a bunch of that model, and someone gave me 4 of those about 2 months ago, but I really didn’t pay attention to what was in the electrical enclosure. BTY, the 4 machines like yours and a Hurco Hawk cnc is worth $1,800 at the metal scrap yard. They were well worn out, or I would have kept them.

Good Luck
Buck

[Al_The_Man]

Originally Posted by zook Since the servos are tach, I am going to need some encoders. Any suggestions? I am probobly going to go ahead and replace the limit switches as well. Any suggestions there? Mach3 I still need a power supply 80v 20 amps. Any suggestions? Do I need a power supply for each servo?

Tach and encoders both have different functions, one does not really replace the other, there must have been encoders or resolvers on the original, (resolvers would have to be replaced).
Tach are not used on modern Torque mode amplifiers.
Look on ebay, Renco are dumping NOS for $20.00 each ($150.00 encoders).
Limit switches: I use Microswitch Hermetically sealed 914CE1 style, again ebay.
What is wrong with the original power supply?
Otherwise, search in the forums, there are many posts on putting one together, fairly easy, there is a guy on ebay (again), that is building Toroidal Tfmrs in many configurations, the beauty is, if you get your required servo voltage, an simple overwind can be added for auxiliary supply, i.e. 12~24vac.
Al.

[zook]

Buck:

Thanks you for all of the info!!

Just a few questions:

The Hitachi vfd is $255. The Automotion is $289 on their website. Is there a cheaper place to get them?

Your message about the drives became jumbled up. I do understand most of what the gecko insturctions are talking about. My shop partner has a scope and knows how to use it. You did say that the big hurco (EC) servos would burn up the smaller drives right?

The hurco servo amps take in 120AC. They must each have thier own supply on the amp board. I'll look at the diagrams again tonight.

Thanks again.

pat

[zook]

Originally Posted by Al_The_Man Tach and encoders both have different functions, one does not really replace the other, there must have been encoders or resolvers on the original, (resolvers would have to be replaced). Tach are not used on modern Torque mode amplifiers. Look on ebay, Renco are dumping NOS for $20.00 each ($150.00 encoders). Limit switches: I use Microswitch Hermetically sealed 914CE1 style, again ebay. What is wrong with the original power supply? Otherwise, search in the forums, there are many posts on putting one together, fairly easy, there is a guy on ebay (again), that is building Toroidal Tfmrs in many configurations, the beauty is, if you get your required servo voltage, an simple overwind can be added for auxiliary supply, i.e. 12~24vac. Al.

Al:

The hurco amps take in 120vac. They must each have thier own power supply. I'll look at the schematics and see if i can pirate them off of the boards. Might be better off selling the amps and buying new power supplies though.

There are no encoders on the servos. I checked both the schematics and the motors themselves. just 2 wires to drive the motor and two wires wired to the tach. What do you think?

Thanks.

Pat

[Al_The_Man]

Originally Posted by zook Might be better off selling the amps and buying new power supplies though. There are no encoders on the servos. I checked both the schematics and the motors themselves. just 2 wires to drive the motor and two wires wired to the tach. What do you think? Thanks. Pat

You probably will be better off getting torque mode amps rather than the existing velocity type (tach feed back).
Just disconnect the tachs and remove the tach brushes.
There must have been some kind of feedback to the CNC controller, either encoders on the ballscrews (or resolvers).
Tach feed back is not positional, only velocity.
Also If you keep the existing amps, you would have to fit step/direction to analogue conversion boards for Mach.
Al.

[123CNC]

Sounds like you may have Randtronic Amps, and of course Al is right. On my little bit newer Huroc than your SM1, the tach/ velocity control loop is feedback to the drive, and encoders feedback to the controller for position.

If your dedicated to the Mach route, then ignore the following. If you know your drives are good, and likely tuned to your servos, another option is to go the EMC2 route with Mesa cards which will give you analog outs to the drive and accept the encoder input back to the PC/ controller. Its an option, which will require a little more investigation on if it is for you.

Al or others may also be able to advise you, but a Galil card (certain models) may also allow you to retain your servo drives and use Mach (requires more investigation).

[jeep534]

the Geko servo drives are not big enough ( current capacity) to run those servo's the larkin drives seem to be the ones currently on the market that will handle the larger servo's and take step and direction imput. Glentek is making one as well but they only want to sell you their drive motor combo.

just another opinion
archie =) =) =)

P.S. there is a guy running a Hurco on larkin drives with info posted here on the Zone in the larkin forum

[DonnieET]

Pat

How your project coming along? I just got a SM-1. If you had the puppy in the back of your truck you had a load! Was that you or Al that had a schematic for the SM-1?

Where did you get the Hitachi vfd? I used several of the Automation direct GS2 drive and had good luck with them.

Donnie

[Buddy1]

The SM1 came with encoders on the X and z motors and an encoder on the y axis ballscrew. Someone may have robbed them. The Hurco Amps and motors are rated for 80vdc. I would not recommend US Digital encoders (unless you are building a conveyor belt. jk). Use something more durable. Why a VFD when the spindle is a vari-drive system.

[DonnieET]

Why the VFD? Have seen the price on a good phase converter? At $289 you get a solid single to three-phase converter that happens to be variable speed. And when the hurco control dies you can easily control speed of the spindle and monitor the motor load with a new control. Plus when the variable sleeve wears out you just replace it with a timing belt and a lot of problems are fixed.

With the way it's looking replacing that BX control maybe soon that later. Anyone have a wiring schematic on a SM-1?

[tjs88yj]

I have the mechanical and wiring schematics for my 1984 SM-1, just a paper copy, what part are you needing? I would like to know how to drive my mill using EMC2 or similar with my current Hurco servo amps.

Tom