Proximity Sensors on x, y and z axes, how do I set them up as inputs?

[IrishMike22]

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

[Tweakie.CNC]

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.

[IrishMike22]

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

[Tweakie.CNC]

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

Tweakie.

[djc]

...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.