[Edster]

Dude, you have to read the names above the posts before you start responding. I never said anything boastful about ServoSoft, that was some other guy at the start of the thread! If anything, I knocked them a bit by mentioning two other companies putting out superior products at a much lower cost!

The SoftServo system has a 2000Hz servo update rate over EtherCAT and most systems are even slower. Of course, it's rather rare that one would have to do 10,000 consecutive orthogonal moves!

I understand it was mactec54 that was claiming the servosoft was the best high speed control, but he wasn't the one that implied okuma or fanuc don't have enough processing power to use all the data from their encoders. Or the encoders they use are overkill for hsm.

Having orders of magnitude more encoder counts won't give you any more accuracy if the software is thinking in tenths and the mechanical side is only accurate to tenths.

What software? Your cam software? The machine's control's software? Just because you can't enter a command smaller that .0001 in the control doesn't mean the control isn't moving the servos in smaller increments. If your theory was correct and you wanted to move from 0,0 to .0001,.0001 would the servo jump .0001 in x or y first. It's going to take a bunch of small steps to get there and the resolution of the servo system is what determines how many steps. Hence the point of 16 million count encoders and nano interpolation. Nano smoothing and nurbs based interpolation address the issues of short line segments generated by cam software.

In a high quality ballscrew setup with pretensioned ballscrews and double ball nuts that are preloaded against each other, how much backlash do you think there is?

What about machines with linear motors with no physical backlash. Would nano interpolation be overkill there.

[Drassk]

Ed,

I don't know how much more clearly I can put this, but here goes: I'm a grown-up. When I talk in generalities about control equipment, you probably shouldn't assume that I'm trying to 'my dad can beat up your dad' you or your gear. I'll address you if I'm talking to you and I'll explicitly say if I think some piece of equipment is sub-par, because that's how grown-ups talk.

(Yes, I am explicitly questioning your maturity)

I noted the SS refresh as relatively slow but still faster than many controls...for example the giant percentage of CNC machinery made in the 1990s and still in service. Most of my equipment is from that era. Nothing about you in there.

How you would surmise that a minimum of ten counts per axis per move increment translates into one-shot motion jumps is a mystery to me.

I originally thought you were just a little underinformed and wanted to learn, but I was wrong about your motivation for participating. If anyone who wants to understand this stuff has any questions, I'm still reading the thread so ask away.

[Edster]

What you post a response about what someone posts, right after their post who do you think your addressing?

Your last post says a lot about your maturity level.

[Edster]

Btw, your fadal 4020 looks like a nice machine. Which control is on it? Couldn't tell from the pic on your website.

[Drassk]

88HS, with a -4 board in it. It's really a 386 on a custom motherboard. The -5 boards have a Pentium on them, and a higher RAM capacity, but odds are that I'll retro it rather than pay to to upgrade to a different 15-year-old Fadal controller. Definitely a machine handicapped by its brain rather than its body.

I found a sheet in the back of the machine with my ballscrew calibration surveys on it recently, which was the biggest wall in the way of retrofitting it (that and being able to be without my bread and butter for a week or two while I trace wires and debug).

[Edster]

How you would surmise that a minimum of ten counts per axis per move increment translates into one-shot motion jumps is a mystery to me.

Bad wording on my part. I was just trying to explain even though we want the cnc to move in say a straight line at an angle it is actually makes a stair step motion. The stair step motion is incredibly small, but it's still there. Nano interpolation makes the stair step smaller.

I have a 94 fadal vmc 15 with the same control on it, cnc88hs with the -4 system. I'm still happy with the machine and it runs parts for us every day. I upgraded the mem to 422k from the 38k it originally came with. I wanted to go bigger but that was the max for the -4 system. A service tech that was out here said I could go up to 16mb with the -5 system, but he said it wasn't worth the upgrade because their isn't much gain from going from the -4 to the -5 system.

Which control were you thinking about retroing to your fadal?

[Drassk]

Bad wording on my part. I was just trying to explain even though we want the cnc to move in say a straight line at an angle it is actually makes a stair step motion. The stair step motion is incredibly small, but it's still there. Nano interpolation makes the stair step smaller.

I have a 94 fadal vmc 15 with the same control on it, cnc88hs with the -4 system. I'm still happy with the machine and it runs parts for us every day. I upgraded the mem to 422k from the 38k it originally came with. I wanted to go bigger but that was the max for the -4 system. A service tech that was out here said I could go up to 16mb with the -5 system, but he said it wasn't worth the upgrade because their isn't much gain from going from the -4 to the -5 system.

Which control were you thinking about retroing to your fadal?

The 10-20 steps to a measurable increment is just a subdivision that tends to be the point past which returns are almost null. In other words, if you've got 20 diagonal steps and you can only see the 0.0001" square then the diagonal looks 'perfect' at that point. If the steps beyond 20 were 'accuracy' steps then your measurable motion wouldn't be 0.0001", it would be smaller, and the machine would be advertised as such. Mechanical limitations mean it's really hard to make a milling machine of any size good for better than a tenth.

My -4 has 180K of memory in it, and I have a bag of the memory chips that I bought a while back to upgrade it but I've been too busy to pull out the board and solder them in. My tech is actually big on the idea of the -5 over the -4; I think it does have a better refresh rate, and the extra memory would be handy in some cases. There are programs I filter more coarsely than I would like because there isn't enough memory on the control and DNC can't keep up.

I'd retro it with either a Dynomotion controller or a Galil. I'm going to build a machine with the Dyno, where I'm not in trouble if there are problems, and if that's solid then I'll go with them on the Fadal. Their platform is really beautiful if you're a nuts and bolts and algorithms kind of guy. 'My tech' is in California and I'm here, so when anything goes I have to fix it myself with some phone support. Crappy when things are down, but over time I've learned an awful lot about what's where and how everything fits together and that'll help a lot on the retro!