Hi Will,
Afaik: Mach3 did its own backlash compensation (I have seen videos) because it just sent signals out through a DB-25 connector. Mo motion controllers then
Incorrect, the motion controller was the parallel port driver. That motion controller is not a separate physical device like an ESS or PMDX SmartBoB but it is none the
less a motion controller, it has code and processing power to take the trajectory planned by Mach and produce pulse streams necessary to drive the motors.
There was a time when Mach3s PP couldn't do backlash compensation. Even when external motion controllers came along not all manufacturers had support for
backlash compensation. The situation is similar today with Mach4 manufacturers adding backlash compensation 'when they get around to it' rather than as a fundamental
function. As Steve points out adding backlash compensation is by no means trivial and there will always be shortcomings with it that no software can solve. He is not
unique in saying 'fix the backlash in your machine, software can't fix your sloppiness'.
Ess looks much more affordable, However: Backlash not fully working. Only controls 4 stepper drivers and it is recommended to buy a BOB as well! So $30 on a C25 BoB. Also no mention of spindle control? Would need another Bob for spindle. Also documentation I have read is VERY unclear as to how you assign and configure the various I/O ports!
1) Backlash compensation is not working perfectly at the moment, backlash compensation will never be perfect, a beta test version is being trialled at the moment
2) The ESS can control six coordinated axes and another six out-of-band axes WITHOUT counting slave axes
3) Yes you need a BoB, you can hook direct to the ESS but if your hamfisted you'll blow the FPGA and then have to buy another ESS. DON'T DO IT!! A BoB protects your ESS
4) The ESS plugin allows you to ascribe an alias to any pin and then assign that pin by name to a Mach signal. The ESS plugin will update Machs plugin to keep them
consistent.
5) Any output pin can be made to produce PWM. All that is required is an amplifier and filter circuit....if you make your own...one opamp, a couple of resistors and capacitors,
OR you can buy a BoB to do it for you.
Once you start adding a couple of BoBs and a power supply for the ESS it is the same or even more than a PMDX-424 which has its own supply and no BoB required
except for the spindle. PMDX have taken considerable effort to make their devices as easy as possible to use.
If backlash compensation is absolutely vital to you either wait a bit for the ESS or stump up the extra for a Hicon.
Craig