Tool setter connection - NC switch from Power (Red-colored) to Input - Resistor or not

[artefact]

Hi everyone,

I'm setting up a MASSO for the first time.
We have a G3 Touch (configured as a Mill).

To connect a probe setter (that will also be used as a probing) I used one of the red-colored Power connector and wired it to two inputs going thru a normally closed switch.
Both inputs were displaying as "High" on the F1 display but are now showing "Low" on Invert.
Pressing on the setter triggers the switch and the signals go High on both inputs.

It seems to work fine this way but I would like to make sure... do I need to add a resistor somewhere?

Thank you
David

 

[zombieengineer]

@artefact

If you are using the "aluminum block method" as per CNCNutz video the correct wiring is a resistor between Positive to the input terminal (this is called a pull-up resistor). You also need to add a wire between the input you just connected the resistor to your touch plate, then you connect the spindle/tool bit to ground (some people drill and tap a hole in their spindle for a permanent connection).

If you are using a "two wire tool setter" then connect a resistor between positive and one of the wires, connect the other wire to the input. The resistor is not essential but it helps protect your controller from "arc and sparks" should the cable to your tool setter gets cut/shorted (the resistor limits the amount of current to manageable levels). Alternatively you could wire this up like a touch-probe.

If you have a "three wire tool setter" then things get interesting (need to ask some additional questions).

 

[artefact]

Thank you for the answer ZombieEngineer

I described our connection method and it is NOT by using the aluminum block method.

It would be considered a "two wire tool setter" as I see it. One wire goes from MASSO Power to the switch COM, the other from the switch NC to the MASSO input. Another wire link both MASSO inputs together.

After asking the question yesterday I realized that the E-Stops are connected the same way.
So to speak, the wire gets "cut" every single time we power up the controller since we have to cycle the E-Stop at each MASSO boot.
The same thing will happen each time we measure a tool length or zero out the Z-axis... we will open ("cut") the circuit by pressing the switch.

As I understand, a resistor would reduce the signal current, which is already very low, to an even lower level. Is that it?
The advantage I would see here is less power consumption.
If it is preferable, should the E-Stop get wired with a resistor too?

 

[cncnutz]

Hi Artefact

The MASSO Estop and other inputs will work fine with full power supply voltage either 12v or 24v without the need for a resistor.
The real problem is if the positive wire of the touch off switch or Estop should accidentally ground the fault current will be very large. This could happen if the cable is run over my a carriage or the cable is damaged by maybe coming in contact with the cutter. Maybe the wire from the positive falls off the Estop switch because of vibration and touches ground. (These have happened in the past.)
At best you will blow a fuse and at worse cause damage to the PSU or MASSO if the 1amp fuse was not installed.

Adding a 1K or similar resistor in line with the Power positive lead you send to your touch off switch or Estop will limit the possible fault current to a safe value in the unlikely event of an accident.
It really is cheap insurance. It will also make troubleshooting a lot easier as well since it will not kill the system dead. You will be able to see what item of your circuit is not working and go from there.

Cheers Peter

 

[artefact]

Hi Peter

I get it now!
I was not seeing the possible short to ground and I now understand that it's different than the standard circuit operation (opening/closing thru a switch).
The inputs are limited but the ground is not! [Here would go the emoji with the little dude that slap its forehead. ]

Thank you both

Cheers!
David