Safely wiring tool setter with Mesa 7i96

Hi,

I have Mesa 7i96 wired with PNP sensors so the with 24V so the common pin is GND.

But now I have this NO tool setter:
www.aliexpress.com/item/4001274229239.ht...TW8wmt6WecOUr--f2gDM

I know that when I connect wire of the setter to 24V and alligator clip to Mesa input, it will work.
BUT the 24V would be directly exposed so someone can touch it and get hurt.
I cannot think of the way to wire it safely unless I connect 3k resistor between 24V and tool setter.

Is that correct?
Thank you

JIri

I would connect the alligator clip to ground and the toolsetter wire to a 7I96
input. I would then add a 4.7K pullup resistor from this input to +24V.

Note that this connection reverses the polarity of the probe detection
so you would need to choose the inverted input source in the hal file.

This way you don't put a voltage on the spindle (which may get grounded via the
bearings, which could cause a detection failure in addition to very slowly EDMing your bearings )

The pullup also means accidentally grounding the toolsetter is harmless
(~5 ma Max) and drops the open circuit voltage to about 12V

Thanks for the clean-up!

Good idea,
thank you very much!

Hi,

I have a similiar issue.

My inductive sensors (Omron TL-Q5MC1-Z) are NPN NO.
So my input gets 24V and gets pulled low when triggered. In the config the input is inverted and that works.

Now i too want to add a similar as mentioned above tool sensors.

The one wire goes to the sensor and the other wire is grounded to the chassis/spindle.

How would i need to wire it to the 7i96 ?

I am really not very electronic savy, i should really get into learning more.

But i do have a set of resistors

If you are already setup for NPN sensors,
you don't need any additional resistors

Basically 1 wire of the toolsetter goes to ground (24V common)
and the other toolsetter wire goes to a 7I96S input.

Thank you @PCW for your reply
I am back at the workshop testing this.
Does not seem to work how i wired it.

So, the 0V of the (24v) PSU is connected to the 7i96s input COM
Inputs 0,1,2 are the inductive NPN NO limit switches.
There is 9.9V between these inputs and the input COM when these inductive sensors are not triggered. and 0.9V when they are triggered.

So i can detect those by inverting these inputs.

I want to use input 3 for the toolsetter.
So in the wiring you suggest would be the same as shorting input 3 and the input COM to trigger this ? I just tested this with some wires, but the input 3 led on the board does not light up, nor does the hm2_7i96s.0.inm.00.input-03 gets triggered in hal-show.

When i do check the two wires coming from the toolsetter , it does give continuity when it touches the spindle.

Where am I going wrong ?

If you have NPN sensors,, 7I96S input common should be at +24V
(so the inputs are activated by grounding)