This requires a separate power supply connected to screw terminals labeled 24V and DCM ground. The I/O ports have E元57N optocouplers for safety. This can be limit switches, ESTOP, PWM, touch probe etc. These input and output ports can be configured as needed for the various functions that MACH3 supports. There are also four input and four output ports. There is no ENABLE output on this controller board Since the board uses a line driver for the step and direction outputs, the connection to stepper drivers is simple. The step and direction signals can be configured as active low or active high in MACH3 ports and pins setup page. This step pulse width is long enough to work with almost every stepper driver available. When the plugin driver is set at 100Khz, the step pulse width is 5 microseconds. I verified this with both short and extra long motion moves. The correct number of step pulses was generated for each commanded motion distance.
I used a logic analyzer to capture and count the step pulses. The step and directions signals are buffered with a 74HC541 line driver. The controller has four step and direction axis output ports – X, Y, Z and A. Slave axis configuration has been tested, the same step pulse was generated on both the X and A axis outputs simultaneously. Step frequencies below 50Khz are better and motor motion is smoother. These pauses can cause rough motor motion. However at higher step frequencies, there are pauses in the step pulse train. Using a microcontroller to generate step pulses is usually more reliable than a PC parallel port. The controller uses a STM32F103 microcontroller to generate the step pulses up to 100Khz.
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