Evening all,

Thanks to the quick shipping and good service from the guys at Warp9, I'm now the owner of two Smoothstepper USB boards.  I have just started setting one up for my mill, and I have a few queries already!  Hopefully they won't sound too silly, and perhaps someone might know the answer?  I would be most grateful for any help if you do!

1.  When I am configuring Mach 3 with the SmoothStepper in the "ports and pins" setup box in the config menu, what should I be entering here?  I can only enable parallel port 1 and 2, and these need an address (a hex number).  Also, the Smoothstepper has 3 ports that can be used?  What should be entered to use the inputs on the 3rd port (do I just enter the number "3" in the boxes that are asking for port numbers?)

2.  Charge pump output.  I was originally planning to use a parallel port output from my laptop, and thus make use of a charge pump circuit for safety reasons.  As I am now going to be using a Smoothstepper board instead, is the charge pump still required? Is it recommended?  Or is the function of the chargepump now not needed as the smoothstepper does effectively the same thing?

3.  Are there any known issues, or features that are not implemented/supported by the smoothstepper in Mach3 at present?  I have read a few threads that mention the odd thing (soft limits?  Backlash compensation?) but not seen a current "list" anywhere.  Maybe this could be a sticky at the top of this forum?

4.  Can anyone give me, or post a link to, any resources that will explain what a differential input is (as seen on the Smoothstepper port 3 input 2), and what benefits it has over normal inputs?

Other  than that, it looks pretty straightforward.  I already have it communicating with Mach 3, but I haven't decamped out to the (bloomin cold!) workshop yet to hook it up to a stepper driver!  I may resort to bringing one inside this weekend if the cold weather continues!

Cheers
Andy

EDIT:  remembered the 4th question I had!

1. You dont have to set up the address in ports and pins for the ports, the plugin does away with the need for that, having an address in wont do any harm. As for what to put in as a port in your I/O etc its just 1, 2 or 3 like you suspected.

2. Chargepump is not required as the SS loads the plugin each time Mach starts so no commands can happen unless Mach is in control. If the SS loses communication its buffer runs dry and then no more motion will happen.

3. Backlash is still not done but softlimits and threading(lathe) are fine, in fact threading is excellent with the SS

4. If your enceder is differential it will have A+, A-, B+, B- . Differential encoders are much less prone to noise. You can get single ended to differential adapters, they are not that expensive from US Digital but you may not need them if the cable is properly shielded and fairly short.

Hood

5.

Hi Hood,

Many thanks for those answers, it is much appreciated!  I'm just off to pick up some 26 pin connectors, and hopefully I'll get the Smoothsteppers wired up this afternoon and tested

Cheers
Andy

I am sure al will run smoothly, the SS must be about one of the easiest addons to set up.
Hood

Good news!  It works

I got the smoothstepper hooked up to a test motor/drive over the weekend, and it is singing away very happily!  The stepping is silky smooth and is running WAY faster than when I was trying to drive it from the laptop parallel port

The next step is to get all three axes wired up, and tested.  One thing I am wondering about now, is the microstepping level that I use.  I'm using 1.8° per step motors, and MDS542 drivers from here: http://www.motioncontrolproducts.co.uk/product_info.php?cPath=26&products_id=3  they apparently can cope with up to 400KHz input, so running the 125µstep mode means a max rpm of 960.  I am using 10tpi leadscrews on all axes of my mill, so the theoretical max speed is plenty quick enough for a small machine (10" travel in X and Y).  Is there any reason why I shouldn't use the largest µstepping level?

Thanks folks!

Andy

The SmoothSteper can certainly handle it as the Max for it is 4MHz, where you might find a problem is with the stepper. I seem to remember Mariss (Mr Gecko) saying any more than 10 micro steps was pointless, why I cant remember but maybe a search of the Yahoo group for Geckos would find that post. The best thing though is just to try it and see if your results are better with one or the other.
Hood

Thinking about it a bit more, using a 10tpi leadscrew means that I'll have 0.0127mm per step using no micro steps, so going to 10 microsteps is going to give me just over a micron theoretical accuracy.  Mr Gecko may well be right that any more than that is just overkill

I suspect the Stepper drivers lose a fair bit of efficiency when asked to switch that fast too

Still, I'll have a play and see what happens!

Cheers
Andy