Retrofitting a CharlyRobot 3 axis CNC
As I checked the 17 pin and charge pump stuff: I inverted the Ampli activation (enable) selection in LinuxCNC and bingo! All 3 axis are working fine now
How 1 motor was working fine without the charge pump?... that is strange, no ?
By the way, I have research some information about the charge pump (or watchdog):
Reuelt : The purpose of the Charge Pump is mainly SAFETY but may also protect material, tools and even the machine from accidental damage.
Mach3 outputs a constant pulse train of approximately 12.5 kHZ on the parallel port 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.
All motors (axis stepper + Spindle + pumps...) won't turn UNLESS the capacitor 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.
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.
Ger21 : I use it in conjunction with a Safety Relay as part of my Estop circuit.
You can't power up the system until the control software is running, and if the software or PC goes out, the system is powered down automatically.
If you're using the Charge Pump, it ideally would tie in to the Estop loop, so that either the Charge Pump or an Estop button will kill power to everything.
The charge pump system makes use of the 12 KHz signal on pin one of the parallel port generated by the CNC software. This signal is only present when the program is up and running correctly. The logic level obtained from the signal can then control either an enable or sleep pin on the stepper motor drive board or boards. This effectively prevents any false movement of the motors while the machine is being powered up or down or even a software crash condition. 0201.nccdn.net/1_2/000/000/18d/ea4/PCPPSV4.pdf
Charge Pump - If your driver board requires a charge pump signal select Charge Pump from the drop down list for the output pin you wish to connect to your charge pump input. The charge pump output is connected to the base thread by Stepconf. The charge pump output will be about 1/2 of the maximum step rate shown on the Basic Machine Configuration page.
blog.dietmann.org/?p=188
With the LPT port solution, the CNC software controls the stepper motors by toggling the pins (step & direction) for each axis according to the needs of the desired toolpath (G-code).
A problem of the LPT port is the undefined state and behavior of some pins during the boot sequence of the computer. If your CNC mill is already activated, this might result in undesired motion of the CNC mill. In order to prevent this behavior, some stepper motor controllers have a built-in charge pump. This charge pump requires a defined squarewave signal at a specific LPT pin to enable the stepper motor controller. If this charge pump signal is missing the stepper motor driver won’t perform any motion (steps). The signal is only generated when the CNC software (here LinuxCNC) is running properly and no emergency stop condition is met.
HAL tweaks in the post
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