Originally Posted by Max I'd like to know some thoughts on whether it's better to build using Software and Driver boards made for the Serial Port or the Parallel Port. |
In MS Windows the priorities are controlled by the operating system. Until about 3 years ago, there were no applications that could achieve more than a couple thousand steps per second.
Since that time, parallel port controllers have been released that achieve up to about 45000 steps per second. (There are also a few bus based controllers for windows, but the price is considerable higher)
There is now a Serial port controller that will achieve 128,000 steps per second.
A serial port controller uses a higher level communications protocal to communicate with an external dedicated microcontroller. In this manner many bits passed through the parallel port are reduced to a simple line or arc command. The dedicated microcontroller easily processes the motion commands into discrete step and direction signals for multiple axes.
Parallel port controllers usually require a breakout board to manage the electrical interface from the computer parallel port, to the motor driver electronics, limit switches, relays, etc. of the cnc machine. The external controller board provides this functionality with the serial port systems.
With Windows, the cost of parallel port software and a breakout board is about the same as a serial port controller board and software.
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