The Y axis rails are 1" diameter. Got the Y ball screw and drive installed and running yesterday. Initial tests are going nicely! Mach3 is running smooth on Windows Server 2003.
Question to the masses...any reason why bringing the proximity output voltage (12VDC) down to 5VDC with a potentiometer is a bad idea?
Using a potentiometer set up as a voltage divider is OK as long as the switch can supply enough current for the potentiometer. You could use a couple of resistors instead, that way you won't accidentally move the pot and supply too high a voltage to you 5V input. you could make a voltage divider from a 6.8K and 4.7K resistor. At the junction you would get 4.9V when feeding it with 12V.
The higher the voltage you use for switches sensor the better. Well to a limit. :-) A system using a higher voltage is usually less susceptible to noise as the noise is a smaller percentage of the overall signal. Also for mechanical switches, there is some voltage loss across the switch due to resistance in the switch contacts. Additionally, a higher voltage cleans the switch contacts better when it closes.
There is a reason why industrial systems use 24Vdc for their signalling. In the end you need to get it down to 5V to get in/out of the parallel port, and it is best to do this close to the PC.
Cheers,
Peter.
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