Mach3 usb with 2nd probe [resolved]

[rmaltais]

Hi,

Why i can't build a firmware with 2nd probe? It is possible to use a door input for this probe because i don't use it. Can i change firmware for use this plug-in?

thank

[nickshl]

Why do you need it? Normally Open probes can be easily connected in parallel. Normally Closed more difficult - electronic probes can't be connected in series. However if one probe is electronic(like 3D touch probe) and other probe is just a switch(like tool setter) those probes can be connected in series(output of 3D touch probe trough switch in toolsetter to controller input). But in this case both probes have to be connected to do measurements. If you don't need to have sensors connected whole time, it easier to use GX12 connector and connect particular probe before measurement.
The biggest problem with more that one probe input - GCode doesn't support that. As result there no way to use two inputs with NC sensors when one sensor is disconnected, but when I want to make measurement with another. There is no way to tell grblHAL "Ignore first probe, and use only the second".

[rmaltais]

Hi,

The problem is that my tool probe is NC and my electronic probe is a NO signal. I have to reverse the signal in the controller every time I want to change the probe. I think I will have to install a relay on my tool setter to invert the signal and connect it in parallel. If not, is there another solution?

Regards,

[nickshl]

Of course there is another solution. You need two parts: NPN transistor(2N2222, BC547 or similar) and resistor.

This schematic converts NO sensor to NC sensor. Current trough base should be about 5-10-15 mA. You can use GX16 connectors(relatively cheap on AliExpress) - those big enough and you should be able to place transistor with TO-92 package and resistor inside connector(on a sensor side).

[terjeio]

I am working on a solution to this, by defining optional inputs as aux inputs and claiming them only when configured. The Web Builder has to be updated to keep track of aux pin usage - on my todo list.

[rmaltais]

Thank for all your work, very appreciate.

[rmaltais]

Hi,

I finally made the assembly with a BC547 and a 22K resistor. It doesn't work and I tried a 47K resistor without success. In fact, if I test the assembly outside of my circuit, it works on my multimeter and I have a 100% open circuit. If I place the same circuit inside with the PSU which also powers my probe it makes a weak link which closes does not fully open the circuit so it always remains active. A very weak LED tells me that the state is active.

[nickshl]

What is your sensor supply voltage? The resistor value seems way high to me. For 5 mA base current at 5V you need resistor 5 / 0.005 = 1k, at 12V 12 / 0.005 = 2.4k.

[nickshl]

I am working on a solution to this, by defining optional inputs as aux inputs and claiming them only when configured.

Is there any plans to add which sensor to use? Something like G38.2.N, where N - is probe number, and if it omitted(for backward compatibility), then all probes is monitoring. Or any other way? I don't want to have NC 3D touch probe always connected, but I have to in order to use tool length sensor...

[terjeio]

Something like G38.2.N, where N - is probe number, and if it omitted(for backward compatibility),

This is non-standard and will require changes to the parser since 38.2.N cannot be converted to a float - so I say no.

Or any other way?

You have shown one option above, plugin code that adds a M-code or switches probe input automatically is another. Automatic switching is possible if a toolsetter is located at a fixed position (G59.3 is used to specify that) - an event is generated if probing is within range.