Hi Reinhard,
I already have an ESS, but I consider feed override so important, that I'm not sure, whether to start with ESS or sell it and go for DSPMC from start on.
Mach4 with the ESS controller has feedrate override and as far as I can tell by standing at the machine operating it seems to be instantaneous.
If there is anything that the ESS lacks is analogue inputs. PoKeys do a good job and PMDX also have a couple of analogue input channels. Of course Galil
do them as well but at a cost as do Vital Systems.
Vital Systems boards offer closed loop operation, if you pay the extra, but if I understand it reads an encoder and produces a high resolution analogue voltage
to drive a DC amplifier which in turn drives a DC servo. DC servos are perfectly capable but pretty old school by now....additionally have you seen how expensive
they've become? Bang for your buck go for AC servos, the loop is closed by the drive, and usually by the same manufacturer with very VERY good results, better
than I could program a PID loop anyway. If you accept as I do that the drive/AC servo loop do as good or better job than any controller then you have paid
a premium for closed loop feedback which is not really required.
A worthwhile feature offered by Galil, Vital Systems and Pokeys is the ability to micro program the controller. You pay extra to have Vital Systems boards do it.
The advantage is that you can use that fine grained programming ability to close control loops OTHER than motor loops. Galil have lead the field in this regard
for many years.
Warp9 have a plan to release an API for the ESS. To be honest I can't see that it will happen quickly but it would add some of the ability of the above. It doesn't seem
likely that it will ever match Galil for this style of programming.
If you already have an ESS I would carry on with it. The ESS plugin lacks at this time THC and lathe threading but are being worked on.
Those extra features including closed loop servo control and microprogramming on a Vital Systems board are going to cost $1500 or more.
The first is no question. Learning is my main hobby Smiley
... but the second is.
The ESS will provide plenty of learning opportunities!
Craig