Limit sensors on Hardinge CHNC-I lathe

We are retrofitting a 1986 CHNC-I that originally had the General Numerics control. The axis servos and drives were previously replaced with Parker/MTS brushless motors/drives, and we now have those working very well. Now, on to the home and limit sensors. Taking them off the machine, we just see "MicroSwitch, Freeport IL", no part number or anything! The parts book shows a Hardinge part #, but that doesn't help much. Does anyone know what these sensors are? I'm pretty sure they are actually sensors, not mechanical switches, as they don't click when actuated.

The sensors all have red, black and brown wires. Typical in industrial controls, red is + supply, black is ground and brown is the sensor output. The wiring diagram kind of confirms that, but we don't know what voltages these sensors should be supplied with.

Thanks in advance for any info anyone can provide!

Jon

A photo of the switch might help id it.

It looks like the small microswitch, I guess about 1" long and .6" high, and about 3/8" thick. It is the same size as the mechanical microswitches, but we think this is actually some kind of sensor in a matching physical package.

Jon

im working on a hardinge Superslant with a General Numerics control, it had this cam based limits all in the resolver, but it also has capacitance sensor for a coarse home. the micro switches i think are red and have 3 wire in the connector, only two went all the way to the controller. you can check the continuity, if it is a switch it will have continuity on two wires and will change to a different wire on activation. if it is a sensor you may have continuity on 2 or all three wire and it will not change if you activate it. switches will also click in my experience sensor don't. all my sensor on my hardinge run on 12 volt, i have both 12 volt and 24 volt in the controller, but the 24 volt seem to only run the ssr

also most sensor i work with are Brown +, Black Out, and Blue -. some but not all 5-24 or 5-36 volt. if you can get one on a bench start with the lowest voltage your controller has in its box

found more info here
www.centroidcnc.com/downloads/centroid_HardingeManual.pdf if this match your lathe the switch are covered on page 57

WOW, thanks for that Centroid manual, I think it will be a BIG help! Picture 5.8.13 on P54 looks exactly like the sensor I uncovered to look at. P 57 was basically blank - it just says parts list. But, other than the exact wiring, it confirms what I needed to know. We do have wiring diagrams for the machine, so that should confirm the + V and gnd connections to the sensors.

Thanks again,

Jon

Those are " solid state " switches. They are similar to a Hall effects switch. They can be replaced with standard mechanical micro switches . It seems I ran into a similar issue some years back, I sent a picture of the switch to Digikey and they had a replacement. They were inexpensive.