Ok I was wrong there, seems the A is not analogue only, think thats Yaskawa that does things that way.
If you give me the exact model of drive I will say for sure if it can accept Step/Dir
Hood

Yes, they are the S version.

It all depends on what type of performance you are wanting from them, if you want to get the best out of these drives/motors then I would go with one of  the CSMIO products as they will help you interface to these drives much more easily.
The CSMIO/IP-M is the lower end version with only 4 axis and 100KHz pulsing but it would work out almost as cheap as getting a decent BOB but will give you the benefit of analogue I/O and  differential Step/Dir and also 24v I/O.
If wanting more performance then the IP-S would be a better choice. All depends on what type of machine you will be using them on I suppose.
Hood

model is Mitsubishi MR-J2S-40A

Yes they will be fine.
Hood

Wow, see there, you got a lot of responses already!

Mitsubishi drives (and to a degree, all industrial drives) are tricky to interface with Mach becuase they use 24V signals  . . except for the step/dir . . which are 5V differential.

You can run the step/dir single ended as shown in the manual if you follow the diagram precisely, however, since you have to drag out the soldering iron and some chips, you may as well do the coversion to differential.

What is a differential signal and why is it good?

A differential signal is one in which the signal is divided into a positive and matching negative voltage on separate lines which are twisted together in the cable. The theory is that any interference picked up will be picked up equally by both wires. Since the wires are opposite voltages, the inteference will automatically cancel at the recieving end.  This is why CAT5 and CAt6 cabling can be unshielded I am told. If I have this wrong, some of the electron guys can chime in and correct or add to what I have said.

Back to the Mitsu; what you have to be VERY careful of is that the OUTPUT side of the drive is not protected and is very easy to overload  . .  i.e. magic smoke  . .  bye bye drive.  The manual has clear diagrams on how to connect loads to the outputs, but it also assumes that the reader understands the concepts and can do the calculations needed so while there IS a diagram, there is little else in the way of instruction or guidance for the novice.

A very large problem is that there are posts in the CNCzone forum that detail exactly how to wire the Mitsu  . . incorrectly  . . and following those instructions will instantly fry your drive.

The method I took was to develop interface boards that isolate the 24V Mitsu signal from the 5V TTL BOB signals. The Mistu can be configured different ways, but I chose to have the signals be 'ON' when they are grounded back to the Mitsu. Here is one of those places where RTFM is in order if the options are interesting to you.

So, in a nutshell, I run the Mitsu OUPUT signals to an opto isolated 'switch' which then takes the BOB's own 5V signal and sends it back to the BOB. The Opto draws an infinitesimal amount of power which cannot hurt the Mitsu output and it 'switches' the BOB input on and off. A side benfit of this scheme is that teh voltage difference is taken care of and the drive is completely isolated from any 'events' which may occur in the BOB .  . for example an incorrectly installed solenoid or other coil.

On the input (top the drive) side I do the same, but in reverse. The 5V BOB signal goes to the input side of the opto and the 'switch' side of the opto in turn routs the Mitsu 24V signals to the MITSU ground . .  note do not mix or connect the signal grounds. DO ground the Mistu drive FRAME to the CNC earth ground.

The same methodology applies to the Mitsu J2S and the newer Mitsu J3. The only difference being the J2S has its own internal 24V supply whereas you ahve to supply the 24V to the J3. Here are the interface boards:





 

Simpson have you seen the CSMIO controllers, they make interfacing Industrial hardware a breeze Its one of the reasons I never continued with the diff, 24vI/O bob I was going to be making for myself.

Hood

Simpson have you seen the CSMIO controllers, they make interfacing Industrial hardware a breeze Its one of the reasons I never continued with the diff, 24vI/O bob I was going to be making for myself.

Hood

No, but I'll check it out. Thanks!  Making PCB was fun at first and I was all amazed with myself that I could make them . .  but now that I over that initial euphoria, it is just another task . . and a PIA at that.

I have the Digital Signal Synthesizer, the Swapaxis function and the Differential driver all combined on one board. This eliminated a ton or wiring and also some noise issues. I'll be keeping that board, but it would be nice to have a BOB with the 24V I/O built in. If the I/O is isolated, I would be up for trying one out, especially if they have additional I/O beyond the two PP assignments.  I think you mentioned analog inputs as well? That might be useful.

A Pokeys board is sitting on my desk, but I have only had time to fire it up and see if it would solve my I/O problem and it seems it will, but I do not have tome right now to work on the task I have in mind for it.

I took a peek at the CSMIO and it looks like a great product. I would need the 6 axis version and an extra IO module to duplicate what I have now and the cost would be US$850 for that setup.

While I despise the USB smoothstepper that I am using, I don't think I hate it $850 worth at this point. I have not been able to spend time keeping even semi-current on the new Ethernet smoothstepper, but I recall that early reports were all favorable. If the new smoothstepper is a good part, then there would need to be some compelling reason to spend 3 or 4 times that cost for the CSMIO.

I am currently using 5 axis + spindle and might be adding another axis shortly, so the low(er) cost 4 axis CSMIO is unfortunately not an option for my application.

It looks to be an interesting option to consider for my new mill which will be built hopefully early next year.

The ESS is a much nicer product than the SS, I still think the SS was good and I never really had any of the issues others seemed to have. One thing that still bugs me about the ESS is the step/dir spindle control still has its glitches and I waited a long time for it to be sorted but unfortunately it never was. It may get done at some point but  when I have no idea.

Regarding the CSMIO, yes it is more expensive but when you look at what you get it starts to look cheaper. Firstly everything is integrated into nice din rail mountable boxes. You have the spindle control built in, the Analogue inputs built in, plenty I/O with expansion capability, differential Step/Dir etc etc. When you start to add up a ESS, a dual port breakout, spindle controller (if analogue spindle) means of getting analogue ins for FRO etc,  line drivers, conversion boards for 24v I/O then it doesnt seem to be quite as expensive in my view. Also there seem to be more possibilities, rigid tapping I think will be one of them, already the encoder module for threading takes the spindle encoder in and even altering the spindle override whist threading the axis seems to track it very well. I have just got the wee lathes axis wired today and I managed to do a test for threading whilst altering the Spindle Override and it looked good, still a few potential hurdles to overcome but things seem to be progressing, Heres a vid of the wee lathe tested today.
http://www.youtube.com/watch?v=HC1PK6uD26U
Hood