Proximity Switches

[kingcreaky]

Ok

Following on from the thread the other day regarding these inductive proximity switches. And after you have pulled yourselves back together after reading Jonathon build thread which im sure is going to be the topic of this week....

TL-W5MC1 5mm Inductive Proximity Sensor Detection Switch NPN DC 5-24V | eBay

Ive got the one on Y working, using the below wiring, however as im running two on the X (for autosquare) Im having problems with interference and I wonder if im missing a diode or something to stop feedback from one to the other?

essentially, if I wire just one... say just to pin 11 its fine, but as soon as I put two in place (ie to pin 12 aswell) I notice false positives on pin 11 if you follow?

If I do need a diode? or an additional component id be grateful for a recommendation