Hi Guys, I am a relatively new user to Mach 3 CNC software but at the moment I am using it to move a 3 degree of freedom traversing mechanism which will be used to orientate a probe in a wind tunnel! It is powering the stepper motors but I also have proximity sensors which I have wired as inputs into the system to stop the motors from going too far. On Mach 3 there are 5 input ports but I need 6! A home and a -- for all three of the axes! I have configured the proximity sensors to go from a high signal >2.4v to a low signal <2.4v. I thought this would trigger the active low configuration in the inputs tab under config.  I was wondering would anyone have any information on how I might get these proximity sensors to work and to send an input to the Mach 3 software to stop it. Any help would be greatly appreciated, this project is part of a PHD I am undertaking at the moment in Ireland.

Best Regards

Micheal

Hi Micheal,

To be sure of detecting the logic level change at the parallel port you need to improve the output of your proximity sensors so you get a switch between <1Volt and >3.5Volt. A simple transistor switch for each sensor should be all that is necessary to achieve this.
If you really do need 6 inputs you could add another parallel port card to your PC.

Tweakie.

I will try that Tweakie thanks for your reply!! I was also told not to wire an external voltatge source to the input pin but to take the voltage thats coming out of the input and have a switch between that and ground! Does that make any sense?

Micheal

Correct, but the inputs may still need a weak pullup to positive (10K or so) something like this.

Tweakie.

...On Mach 3 there are 5 input ports but I need 6!

Easiest and cheapest way is to install a second parallel port on your machine. Above this, there are other options including Pokeys and various ModBus devices.