So I've got an old Bridgeport BOSS 3 that's been converted to run under Mach.  I didn't do the conversion, I bought it already set up this way.  It runs very nicely, but there's one quirk that I don't really like, and that's the VFD.  The machine is set up so that if I set the Varidrive to 2000 RPM, the output from Mach to the VFD will have more or less the correct speeds ... but I don't get the same torque that I'd get if I just use the Varidrive.

What I've been doing is just putting values of S2000 in my programs (that gives me 60 Hz, more or less, at the VFD) and then using the Varidrive to control my actual spindle speed.  This is annoying because when I'm doing my CAM stuff (I use Autodesk Inventor HSM), I get screwy values for my SFM and chip load, plus I have to remember to manually set my speed to 2000 for every tool.  (Yes, I know I could just edit my tool library for the default value, but I haven't gotten around to it yet.)

So.

What I'd like to do is tell Mach 3 to just ignore the S command and just always give a command of 2000 RPM to the VFD.  Is there any convenient way to do this?  When I set the pulley max / min to 1999 and 2001, that doesn't seem to work - if it gets a command outside that range the spindle doesn't turn on.

Thanks in advance!

Just set up(program) your VFD to always use 60 hz and let Mach3 turn ON /OFF the drive .

(;-) TP

Just set up(program) your VFD to always use 60 hz and let Mach3 turn ON /OFF the drive .

(;-) TP

Ideally I'm looking for something that's just within Mach itself ... if I have to reprogram the VFD, I will, but I'd prefer not to.  I was hoping there was just an option button somewhere that I had somehow missed ...

Seeing as no one knows exactly how your spindle is setup I do not have anything else to offer.

The only other option is to MOD your cam POST to only output S2000.

(;-) TP

Seeing as no one knows exactly how your spindle is setup I do not have anything else to offer.

The only other option is to MOD your cam POST to only output S2000.

(;-) TP

Nothing in the hardware should matter for this - but it's a small Hitachi VFD feeding the stock Bridgeport 2hp motor then into the 2J Varidrive head.  Mach just sends PWM commands to the VFD.  I can reprogram it without much issue, I just don't feel like it ... but it looks like I'll need to.  Bleh ...

I was just hoping - vainly, it seems - that Mach could do it in software.  Read "M3 S1500" or whatever and ignore the S part, only ever sending the 2000 signal to the VFD.

no way to ingnore it.
but if you realy want this, macropump is your friend.

on e single line:

code "S2000"

will always "overwrite" teh spindle speed of GGode.

Just a thought, but it may not be a great idea to continously write to the Gcode buffer in that manner ( ten times per sec).  Maybe Maybe not (;-)

I would write directly to the DRO and quaulify it so that IF it is already set to 2000 ignore the write.

If (DRO) <> 2000 then
    Write to the ( DRO,2000)
End if

Hi BR549,

Just a thought, but it may not be a great idea to continously write to the Gcode buffer in that manner ( ten times per sec).  Maybe Maybe not (;-)

I would write directly to the DRO and quaulify it so that IF it is already set to 2000 ignore the write.

If (DRO) <> 2000 then
    Write to the ( DRO,2000)
End if

thank you, did not think about this.

so the code would be:

If GetDRO(18) <> 2000 then
    SetDRO(18,2000)
End if

Thomas