Denford Software & Machines

I've been having a spell of bad luck with my machine....

My original problem with this cyclone before everything else started going wrong was a slight fault on the x axis servo. The drive was smooth until it required slow feed rates, then the movement was more of a judder. Turns out after much research and testing the servo has a feedback problem due to a faulty encoder and commutator signal. The servo system uses Parker BL30 drives with ML2340A-10 brushless servos. It seems that I can't get a replacement motor for love or money, nor can anyone offer a repair. So, I'm in a bit of a predicament.

I've been toying with the idea of replacing both drives and motors with modern AC servo drives. My Parker drives are controlled by -/+10V analogue signals and feedback encoder signals to the control, which some modern drives are capable of. The only foreseeable problem is that the encoder line count seems to be much higher on the modern servos. So basically I'm wondering where I would find the parameters that tell the control how many pulses to receive per unit of travel? I have a bit of experience in this with mach 3 and I've started a system under linux cnc, so hopefully its as easy as re calculating the mechanical drive into encoder pulses per unit and changing a value in the parameters?

I'd really like to keep this cyclone alive as it seems to have done hardly any work in its lifetime and is in great condition

You should have a .OPT file which you can open in a text editor. It may be TU150.OPT or CYLONE.OPT or similar. If you could post the file it may be easier it work out which line to change or add. Look for scaling factor or pulses per mm.

Thanks for the reply.

First problem is that I can't read the floppy disk just yet, my oldest pc uses XP, which won't read it. I'll try and find something with win 95 or dos etc. I had just been looking at the files available on the denford website under the dos section. There is a .opt file there but I can't see any obvious parameter that relates to pulses or scaling.

My machine has serial number: 80625C, August 1998 dispatch date, software version: 1.47, electronics serial number: OC00116616 if any of this helps?

I have attached a copy of the electrical record sheet which has the original option file. Not sure how we altered the steps!

Ok, I've just got the file from the diskette I'm using, but seems that you beat me too it! Here it is anyway:
I can't see anything obvious in there the might suggest how the steps are calculated.

Maybe its easier if I can get the manufacturer of the new motors to configure them the same? Also, I'm not sure what the maximum pulse rate would be? The pulse rate from a 1000 line encoder is 4000 and 10,000 from a 2500 line encoder, so it might be too fast of the system to perform at any use able feedrates?

Right ok, it seems that my servo manufacturer can't supply a servo with a lesser encoder line count than 2500 lines, because it won't work with the drive or something... So I'm up against a wall really. I'll have a look through some of the other files on the floppy disk as this must be loaded at start up surely?

If you're replacing the servo and drive, then most modern drives that have an encoder out option will allow you to scale the output, so the controller sees a reduced encoder count.

I'd try contacting Zapp Automation, as Gary there really knows his stuff and is very helpful
(I'm hoping this recommendation doesn't break any forum rules, as I'm just a satisfied customer!)

Thanks for the info. I've ordered my motors and drives now from the manufacturer. I've been advised that, like you say, the encoder output can be scaled from the input to give the desired pulse count per rev.

Just a matter of interest, how do you get along with your mach 3 conversion? I'm hoping to use my machine with its original control, because I like the fanuc feel, and it still seems to be working ok after nearly 20 years! But its good to have a back up plan... I might even build the bones of a replacement control just in case....

Mach3 works, however I am looking to move over to KMotionCNC, as Mach3 isn't quite as bulletproof as I'd like.
Having said that, it's not given me any hassle for a while now, but I'm sure it'll do something unexpected now I've said that!

Hmm yes, I've had some "issues" with it too on a mill conversion, I'm half way through a linux retrofit on the same machine. Have you ever tried linux cnc? I am far from an expert, but it seems really good from what I've experienced so far, plus the boards are really cheap and extremely powerful. Just a suggestion, this is where I'll go if I have to do a full retrofit on my cyclone any time.

Anyway, I'll speak less about other third party software motion control as this is a Denford forum

I wouldn't worry too much about discussing other software, as there are posts by staff members suggesting it as an option for older machines.

I have briefly tried LinuxCNC, however I found support for doing anything less common to be very hit and miss. I considered using it along with Mesa cards a few years ago, however information was scarce and I struggled to find answers. And I know I'm not the only person to of reached that conclusion. I am aware things have improved lately, but I'm happy with my KFlops and associated boards.
Mach3 probably has the best support base, as most things have been done before, there are plenty users willing to give support, and uses a familiar operating system, so is ideal for beginners, however it does have it's bugs and limitations. Mach4 does seem to be heading in the right direction, but is taking far too long to reach a mature product, and currently has limited support from hardware vendors, which is why I'm heading in the direction of KMotionCNC.

The big issue is lathe support in general is pretty poor, as they only make up a relatively small percentage of the user base. IIRC Mach's estimate is around 10%, but I really wouldn't be surprised if it was less than 5%, given mills/routers/plasma cutters are far more common.

Personally I prefer external motion controllers, as given the computer is the bit most likely to fail, I can just swap the computer, install the software, and be running again. Also, the card costs are pretty comparable by the time you add in all the extra boards needed if you're doing anything more industrial i.e. analogue in/out, 24V in/out.