Kflop vs PlanetCNC USB motion controller

First I apologize if this is the wrong location for this comparison, but I didn't see this discussion fit in the other forum categories and I figure it will get moved where it fits eventually.

I'm considering purchasing one of the controllers in the title but I need some help figuring out which one I want. I tried to read as much as possible from the manufacturers websites beforehand but I haven't found anywhere a direct comparison even though the products seem to be competing.

I failed to find on both sites a targeted user group for the respective products, maybe both can improve the websites in this respect.

What I need - PC USB control of my G540+4 other higher power drives.
I suspect Kflop is overkill for my needs but I fancy its advertised robustness and flexibility, but I fear the programming knowledge required to run it.

SO can anyone please chime in and list the pros and cons for each product ?
The machine I'm running is a home built 3 linear axis (dual driven X) + 3 rotating tables + lathe spindle. Most of the time it will be used as a 3axis router/mill + 4axis work and some 5 axis work, occasionally as a lathe.

I only program a bit of VB Script and I'm very skiddish of the C knowledge required for Kflop, but I am considering it if it mostly involves doing like a couple programs that you only have to tweak rarely.

Production is hobby level currently so I'm not necessarily trying to maximize speeds and squeeze out every bit of IPM possible.

The controllers are comparable in price (if you add the software for planet cnc controller ).

So, to who do these controllers address, for what kind of machines they make sense and for what type of production environment ?
Negatives and positives, future development etc ?
Please chime in and help me understand and decide.

I'm impartial, this is no contest.

Besides being an order of magnitude more powerful, the kflop is made and supported in the US. The caveat here is that you're going to have to learn a little C programming, and this may be a bit painful, but the reason you're building your own machines is probably partly because you enjoy learning new skills and challenges. There are limitations to the kflop that may prevent it from becoming an industrial grade product, and eventually those may be solved, but for the meantime it's an excellent product for the retrofit/home build/ hobby market, and for the projects that you describe . The planetcnc looks like a good hobby grade step motor controller, but having reviewed the specs, if it were my money, it's the kflop ( I have helped setup one application with it).
I offer my opinion as an experienced electronics engineer and programmer.

Frank

Hello,
I would not hesitate at using a KFLOP for Industrial or Hobby. I have used the KFLOP in both and am completely satisfied. The first was at a machine shop on a Bridgeport type knee mill, used every day, from small production runs to tooling.This knee mill has glass scales that KFLOP uses to Close the Loop of the stepper motors, with excellent results. The 2nd KFLOP i have used is on my Mill/Drill here at home that also uses Linear Scales to Close the Loop. The Mill/Drill gets used a lot for keeping our old farm equipment going. :)

There is some "Industrial" controls out there that will charge you a few thousand $ at the least, for the capabilities and options that the KFLOP will give you.
As for the C programming, i have no experience,more of copy and paste from examples and great support from Dynomotion. Once you have your setup finished there is no need to change the C program unless you add more options or such to your machine.

It kinda depends what your needs and budget are. But i also would suggest for a little more money and a learning curve the KFLOP will give you a lot more.
HTH
Troy

Many thanks for your input guys. I was also hoping the discussion would be a bit more technical, like -this one can't do this and this one can't do that.
It's great to hear that a copy&paste job is feasible to make the start-up process shorter.
In terms of price - the controllers, including the software are pretty much the same.

Still - Kflop being more powerful, is this really needed ? I mean, if I get the Planet CNC controller - would that mean that my machine will run slow or jerky ?
Question is - for what exactly is all that computing power needed, will I ever miss it if I get the other controller ?
Sorry for insisting on the technical bits, but I a more practical guy and not just want the fastest sportscar to go shopping lets say.
What about closing the loop on the steppers, is this something both controllers can do ? I read some bits that PlanetCNC cannot do it, can anyone confirm ?
Thanks again for your input.

I just realized Kmotion has axis configuration screen. Initially I thought the config must be scripted, but this makes things way easier. My fingers are itching to place an order...

Quote:

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Originally Posted by isvflorin

.... Question is - for what exactly is all that computing power needed, will I ever miss it if I get the other controller ?
Sorry for insisting on the technical bits

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You raise a good point. Computing power is most valuable when controlling servos because of the control loops (PID plus filtering plus commutation etc.), for controlling step motors it's nice, but not really needed: the proof for that is the many thousands of machines that are happily chugging along via the PC's printer port. Will your step motors jerk or run poorly with the planetcnc? I doubt it, I'm betting they would work just as fine as all step motor controllers.

The Kflop has a a number of advanced features, like the tuning/setup screens that you noted, digital tuning and filtering, a pretty good Mach driver, etc. ... again, more valuable for servos then steppers. Both the kflop and planetcnc products list 8+ axis as features. In reality, I can't think of that many machines (other then robots) that need that many axis, and if they do, they'll have proprietary controls, so I'm not sure in reality who the target user would be for all that stated power. It sounds like you're leaning towards the Kflop, which is probably the right decision all other things being equal.

Frank

Thanks Frank,
I just want to make an informed decision and in this case it kinda feels like comparing apples to hazelnuts - simply because of the hw specs present on the manufacturers website. One manufacturers details the processor of the board , the other lists something we are more used to reading like actual step frequency.

I just read about some issues running Kflop on Win7 and Sandy bridge Dell mobos, this is a bit disappointing since I'm running a Dell precision with a Sandy Bridge mobo...

Anyway, more opinions are welcome, thanks again.

Hi isvflorin,

If all you require is open loop Step/Dir the description and specifications are listed here.

KFLOP's Hardware Step/Dir generators can output step pulses at up to 2.5MHz with very low jitter (sub microsecond). Even if you don't need high rates the jitter introduced by software (or hardware) systems with lower clock rates of ~100KHz can introduce anomalies. For example to generate a 51KHz step rate a system with a 10us (100KHz) clock will output pulses every 20us (50KHz) and then every millisecond put out an extra pulse (1KHz). If this disturbance at 1KHz excites a resonance in your system it might cause a problem like a misstep. KFLOP will generate a very accurate step frequency.

Regarding the Sandy Bridge PC I believe there was an issue when using and old version USB driver. But that has been resolved long ago. Where did you see that?

I've heard really good things about the Planet CNC products. If you are looking for more of a turn-key type of a system than ours I'm sure they would be an excellent choice.

Regards

Tom,
I appreciate your input, many thanks for clarifying these numbers, feels better to compare the pulses vs pulses as I'm used to reading those in the spec sheets.
The more I read into it the more turn key Kflop seems too, especially since I discovered the axis config screens. The Sandy bridge stuff I found searching info about Kflop on the net, don't remember where, good to know it's sorted.
So far, for me the Planet CNC controller is appealing as it is on the same patch of land with me, it seems more turn key, and I must say I like the looks of the software. I have an HD display on my laptop and the fonts in the Kmotion software look tiny :-)
But, the power of Kflop is so enticing...
Generally speaking, I believe this kind of electronics target people that should already know what they need and want, this is a problem for the rest (like me). All I know is that I want to drive my steppers from my laptop, as easier and as robust as possible, but I don't know what kind of power and specs I need for that.
Thanks again and I hope the discussion keeps going, I believe this is a good comparison and might help a lot of people into figuring out what they need (hopefully).

Regards,
Florin

Question:
how to jog the 5th axis with Kflop ? Possible with a gamepad ?

Also - I want to mention that I don't intend to use Mach at all, I keep reading into Kflop and from what I can gather there is actually pretty little coding you have to do in order to run a basic setup. I know - I'm starting to answer my own questions but these things were not evident to me in the beginning. First time I read the FAQ it said I have to be a programmer and I started sweating :) , but now I realize you don't necessarily have to be one. Come one Tom, you are scarrying some people away with that line :D
Regards,
Florin

Hi isvflorin,

To display and to be able to Jog 5 axes in KMotionCNC you need to select the 5-axes Main Dialog "Face" which is selected in:

Tool Setup | Tool Setup Files | Main Dialog Face | Basic 5-axes

See also

The Gamepad only has 2 Joysticks so we only allow it to move 4 axes. But you have the source code if you wish to change it :D

Actually what is preferred is to connect an MPG (with 5 axes selections) directly to KFLOP. This guarantees instant response as it doesn't involve Windows/PC/USB latencies.

We would rather scare away many potential customers rather have a few upset customers that didn't realize what was involved.

Regards

Thanks Tom,
am I correct that with a G540 setup, the Kflop high step frequency is not being taken advantage of ? Or am I missing some basic knowledge ?

Regards,
Florin

Hi Florin,

I think you are correct. A G540 only has 10X microstepping so it doesn't usually need high step rates. At 1000RPM the step rate is only 33KHz. If you have higher microstepping or servos with high resolution encoders the higher step rates are required.

But you may benefit from lower jitter in the step pulses.

Regards

Thanks Tom,
are there stepper drivers that can take advantage of the high freq of Kflop ?
Also - if I understand correctly - in theory I could also program my 3d mouse to jog all axis (even the lathe spindle) ? 3Dconnexion : SpaceNavigator
Or it requires tapping into its drivers and it is not straightforward ?

Thanks again for all the help.
Cheers,
F

Hi Florin,

Any driver/motor that has supports high microstepping and high RPM.

Here is a description and a video demonstrating:

3750RPM @ 128X Microstepping = 1.6MHz


Regarding the 3D Joystick:You would need to modify KMotionCNC to work with that. I see they have a software development kit here. But I'm not sure how well it would work. Most operators like to move individual axis in a precise manner, which might be hard with something like that.

Regards

hello Guy,

I have problem to generate Step and Dir pulse so can any body give me C code to generate this signal for JP7 pin
Thanks,

Hi tranluc,

You shouldn't need any C Code to get basic motion. Use KMotion.exe and Configure for a Step/Dir Output Type.

You need to know what type of Step/Dir Drives you have and how they need to be driven and wired. KFLOP basically supports two modes:

Open collector mode which can sink 5V opto couplers to ground
TTL mode that will sink/source as 3.3V LVTTL outputs

See:
http://dynomotion.com/Help/StepAndDi...StepAndDir.htm

Regards