Why use the CHARGE PUMPS.
Mach3 outputs a constant pulse train of approximately 12.5 kHZ (5kHz for laser) on one or both of the parallel ports whenever it is running correctly. This signal will not be there if the Mach3 has not been loaded, is in EStop mode or if the pulse train generator fails in some way.
If your MACH3 parallel port kernel speed is set at 25,000Hz, it is unlikely that the charge pump will work correctly since the pulse freq could be only about 2K instead of 12.5K.
The purpose of the Charge Pump is mainly SAFETY but may also protect material, tools and even the machine from accidental damage.
A good Break Out board (BOB) with a “Charge Pump Circuit” will stop all motors + Spindle + pumps etc UNLESS the capacitor(s) had been CHARGED PUMPED UP by the pulse train(s) of 12.5KHz from MACH3. That means that nothing will move when Windows Powers Up, or Shutdown or when Mach3 program is frozen - since that (CHARGE PUMPED) capacitor(s) will discharged quickly to 0 volts and all motors get disabled.
People who invested in the Gecko G540 motion controller and use the default XML from Gecko are likely to have the CHRGE PUMP working correctly on MACH3 already.
Cheap BOB that do not have a CHARGE PUMP CIRCUIT often have an “enable pin”. An enable pin will not be as good as the CHARGE PUMP but is better than everything ALWAYS ON. If you use the enable pin, an EStop mode will allow you to manually move the axis by manual cranking/rotating. It will also cool down the motors when EStop button is pressed or limit switch is activated.
If on booting up Windows and MACH3 is not running and you have not press RESET YET but, you find that the spindle is already spinning or pumps already pumping or Stepper motors already activated, you can do something about it...by getting the CHARGE PUMP(s) working.
If External Motion Controllers cannot support charge pump correctly on all the ports they claim to support, there is a danger that MACH4 could turn out to be less SAFE than MACH3 with two Parallel Ports. So feedback to the vendors.
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