DDSCV1.1 3 and 4 axis offline motion controller

[johnsattuk]

And I'd rather stick my Johnson in the mains socket before run machine with two signals sticking into one Motor Output.!! . . . . . Just because it appears to be working doesn't mean it's working correctly.!

Taking this to ridiculous extreams using your method would suggest I could run several identical machines, say 6 machines with just one 3 axis controller each pulling signal from same Motor Output.!! . . . . . Wonder why industry haven't figured this out yet.?

IMO I don't see a problem driving two or more motors from one output, providing the output is capable of providing the milliamps required, I have done this several times without any problems. Most drivers have opto inputs and are isolated from each other, have even used two driver inputs in series on occasion. Since these controllers are digital, they process things sequentially so two seperate outputs are likely to be seperated in time (admittedly very short) which is not the case with using a common output for two motors.

I see videos of multiple headed machines carving many identical models simultaneously, it would not surprise me if they were driven from common outputs.

[JAZZCNC]

IMO I don't see a problem driving two or more motors from one output, providing the output is capable of providing the milliamps required, I have done this several times without any problems.

Did you ever bother to put scope on them and check the timings.? Most that are using the setup just presume it's working correctly because cycle times are relatively short and they don't see any obvious error but that doesn't mean it's not there. Try this with large 3D job that runs for 20+hrs and these tiny timing errors start to show.

I see videos of multiple headed machines carving many identical models simultaneously, it would not surprise me if they were driven from common outputs.

Most of these don't have independent heads they are just one large Z axis and often numatics come into play as well. Those that do will have dedicated outputs, or at least those I've seen have had.
I look after large Italian stone profiling/polishing machine used for counter tops which has 8 heads. 4 each side running on there own dedicated outputs. Each running on servos with Bespoke controller with built in PLC for controlling 86 I/O used for numatic claps etc.

While it can do different job each side mostly it Basicly just mirrors the other and would be perfect candicate for the sharing approach but they don't.! . . . . Sure if sharing outputs didn't have any affect they would take this approach.

[johnsattuk]

Did you ever bother to put scope on them and check the timings.?

Not sure what you would check with a scope, if driving from one output, each driver would be getting the same signal at the same time, where could any cumulation of errors arise.

As most on here, me included, are only talking about driving two steppers for one axis, much of your comments are superflous

[Gary]

What about homing? if you have multiple motors running off one output and you need to home and you have a switch on each axis, how does it handle that?
If you have a gantry and have a motor on each side connected to one output and have one home switch, how will it be able to home both sides accurately?
Also the more load you put on the output the more likely it is going to be susceptible to electrical noise and then you may have one axis loosing a step or two and over time this will add up to a big error.

[johnsattuk]

Homing is obviously a bit more tricky but is quite possible, the controller output goes to two drivers so it is possible to switch each driver input individually with a bit of logic.

As long as you do not overload the controller output I do not see a problem, if you end up taking a few more milliamps from the controller (within it's ratings) any electrical noise will be a less percentage of the signal and will apply equally to both drivers, so do not see why one axis would lose steps without the other.

[John S]

Dean,
Like all devices there will be limitations and I'm thinking that these cheap controllers are for simple one shot machines like a Sieg or Warco X3, WM series mill or simple home built 3 axis router that just reply on 3 + 1 axis and a single spindle, often with ER collet fitting that doesn't allow pre-set tools.

You want more features, you pay your money and move up market to the 990 series controllers.

[JAZZCNC]

Dean,
Like all devices there will be limitations and I'm thinking that these cheap controllers are for simple one shot machines like a Sieg or Warco X3, WM series mill or simple home built 3 axis router that just reply on 3 + 1 axis and a single spindle, often with ER collet fitting that doesn't allow pre-set tools.

You want more features, you pay your money and move up market to the 990 series controllers.

John I agree with you 100% on most of this but lets be honest and realistic here. Not asking for more features would just like it to do what SHOULD and allow PROPER Tool changes without resorting to messing with writing/modding post processors Etc. It states follows Fanuc standard so it should do it.

This not following standards is what concerns me. What else does it not do.? ie: Canned cycles etc.
It's still on bench without motors etc but I quickly run some code thru it and seemed it didn't like G53 either but without seeing what actually happens when motors connected can't say for sure. Not really good or confidence inspiring start is it.!!

[Boyan Silyavski]

What about homing? if you have multiple motors running off one output and you need to home and you have a switch on each axis, how does it handle that?
If you have a gantry and have a motor on each side connected to one output and have one home switch, how will it be able to home both sides accurately?
Also the more load you put on the output the more likely it is going to be susceptible to electrical noise and then you may have one axis loosing a step or two and over time this will add up to a big error.

At the moment i move gantry to the end and hit limit switch. back off till LED lights. Then via PC and servo control software jog other motor to same position. 1 min job, if i dont count starting the PC .


Till now no problem with driving 2 motors from one output even on long, fast and generally quite serious jobs. But now i agree here- that i can be sure only and if i test 100 controllers and they show same consistency. Soon will know as another one is on the way. tHhis time the 4 axis one.

Another thing is that i have not seen a single person use its 4rth axis so its still a mystery there.

[JAZZCNC]

Quick reply is not seeing my space bar! ????

What I was trying to post was, what if you used a high impedance input buffer circuit on all controller outputs to isolate them from the motor driver inputs with twin buffers on one output to run two drivers?

- Nick

At the moment i move gantry to the end and hit limit switch. back off till LED lights. Then via PC and servo control software jog other motor to same position. 1 min job, if i dont count starting the PC .

WTF!!! . . . Who wants to feck about with all this shite when all you have to do is buy real controller that works and provides enough motor outputs to do the job correctly.! . . . Cum-on lets keep it real.!

This particular controller lacks 4 Axis linear movement and shouldn't be bought for machine which requires it simple as that. If folks want to force into something it's not then more fool them.

The rest of it's short cummings are yet to be found and may well be trivial who knows. But in my eyes not following strict protocols like Fanuc standard is putting it on very dodgy ground straight off the bat.!

Surely the whole point offline controller is to limit hassle not introduce new ones which there is NO assitance or help from the only people who can fix the problem.!

And Boyan you can't take out of the equation starting the PC because without the PC your bonkers method can not home.! . . So yes it's very much part the equation if the PC's not on when need to home and if you need it on to use the machine WTF the point of using Offline Controller.?
(Please don't give me "reliabilty" has the reason because I've built more than my fair share of PC based systems that run without any issues and have been running perfectly fine for several years with thousands of hours cutting time under there belts.!)

[Boyan Silyavski]

WTF!!! . . . Who wants to feck about with all this shite when all you have to do is buy real controller that works and provides enough motor outputs to do the job correctly.! . . . Cum-on lets keep it real.!

This particular controller lacks 4 Axis linear movement and shouldn't be bought for machine which requires it simple as that. If folks want to force into something it's not then more fool them.

The rest of it's short cummings are yet to be found and may well be trivial who knows. But in my eyes not following strict protocols like Fanuc standard is putting it on very dodgy ground straight off the bat.!

Surely the whole point offline controller is to limit hassle not introduce new ones which there is NO assitance or help from the only people who can fix the problem.!

And Boyan you can't take out of the equation starting the PC because without the PC your bonkers method can not home.! . . So yes it's very much part the equation if the PC's not on when need to home and if you need it on to use the machine WTF the point of using Offline Controller.?
(Please don't give me "reliabilty" has the reason because I've built more than my fair share of PC based systems that run without any issues and have been running perfectly fine for several years with thousands of hours cutting time under there belts.!)

Cool down please. It works, it costs mere 150euro. That's it. Plus its 500kz and plus that its 4 axis. No PC.


I start the pc cause i am lazy enough to adjust a hard stop and anyway my machine was prepared and designed for easy hardstop squaring. And anyways my pc is sitting there cause all my PC are connected so when i design the file on my main PC i go to garage and there load it to USB. So its always on, plus i have it already.


If not happy then pay 300 for you loved CSMIO and move each axis separately. What? I forgot. It does not square long axis. What? if it drives 2 long motors on long axis you could not use it for A axis.. What? it can noth thread on 4rth axis.

Like you said, going in circles. if you don't like it don't use it. No need to throw this down in a box. Put it on sale here and i guarantee you that you will sell it same day.



I heard a lot of blah blah in this thread but let me tell you again something. My time is money. If your time is not. I have no time fiddling with crappy boards and software or windows, cause 500 pieces wait for me in the garage to be done, i have at least 5 serious projects that need my attention and so on... Only the time the controller saved me last 3 weeks by just pushing the start button and all work flawlessly, if i charge 20 euro per hour i have payed the controller already and again...


And remember here what i say: You can not fight with Chinese industry. They will make a better controller, cheaper and so on. At one moment in time they will sell at least 1000:1 ratio to any other controller on market or software. So the only thing then will be that other maker pretend their stuff is better and better supported and so on. But in reality they will be losing the business.