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General Mach Discussion / Re: USB Breakout board for Mach3
« on: November 23, 2011, 01:26:33 PM »
Hi,
Yes, they work quite well. Although mine burnt out due to insufficient load....
If you look at the schematic/manual of the board, you will see a DC-DC converter to isolate the 5V supply of the board from the USB port (Black rectangle made by Mornsun). The manual does not state this but the datasheet does - the DC-DC converter does not have short circuit protection and also needs a minimum of 10% (of max) current draw to function properly.
You can connect a LED to the 5V output and ensure it draws 20mA and you're sorted as the max current the DC-DC can supply is 200mA.
Other than that, remember to connect pull-up resistors to all the step/dir outputs as they are open collector type drivers and to have a common ground. The PWM speed output is the same. I used 10Kohm. I have not tested the 8 dedicated outputs or the speed feedback. The nice thing about this setup is that you can use another PSU to feed the step/dir outputs (remember the board can only supply 200mA max so it is best to use another PSU) also keep in mind that the step/dir output drivers can only sink about 15mA (check manual) so adjust your pull-up resistors according to the PSU voltage you use.
Double check the max input voltage of the 16 inputs as they are low voltage/current types and you need to include a series resistor if you want to use say 24V as the input voltage.
If you go to the cncdiy website there is an option where you can register to get access to the manual, which is newer than the other one which I found somewhere. I can try and attach it to a later reply as I do not have it on me. I did not read the whole manual but recall that some things were a little clearer.
Anyways, hope you get it working and welcome to the CNC arena
Best Regards
Yes, they work quite well. Although mine burnt out due to insufficient load....
If you look at the schematic/manual of the board, you will see a DC-DC converter to isolate the 5V supply of the board from the USB port (Black rectangle made by Mornsun). The manual does not state this but the datasheet does - the DC-DC converter does not have short circuit protection and also needs a minimum of 10% (of max) current draw to function properly.
You can connect a LED to the 5V output and ensure it draws 20mA and you're sorted as the max current the DC-DC can supply is 200mA.
Other than that, remember to connect pull-up resistors to all the step/dir outputs as they are open collector type drivers and to have a common ground. The PWM speed output is the same. I used 10Kohm. I have not tested the 8 dedicated outputs or the speed feedback. The nice thing about this setup is that you can use another PSU to feed the step/dir outputs (remember the board can only supply 200mA max so it is best to use another PSU) also keep in mind that the step/dir output drivers can only sink about 15mA (check manual) so adjust your pull-up resistors according to the PSU voltage you use.
Double check the max input voltage of the 16 inputs as they are low voltage/current types and you need to include a series resistor if you want to use say 24V as the input voltage.
If you go to the cncdiy website there is an option where you can register to get access to the manual, which is newer than the other one which I found somewhere. I can try and attach it to a later reply as I do not have it on me. I did not read the whole manual but recall that some things were a little clearer.
Anyways, hope you get it working and welcome to the CNC arena
Best Regards