5i25+7i76 wired pendant help please

I think you are making things a fair amount more complicated than necessary by moving the primary I/O to the 5ABOB

I would leave the primary I/O on the 7I76 (step gens limit switches etc) and only add the MPGs to the 5ABOB.This way you can retain the pncconf configuration for most all machine setup and only need to edit the hal file to add the MPG support

Otherwise you have a lot of hal file editing to do

Hi all,

Let me use this thread to explain my problem as it is connected to Mesa 5i25/7i76 (RevB)/MPG configuration

My Setup:
Mesa 7i76 with software mode 2
MPG 6axis from China
12V DC for Field/VIN bus:

• Live - TB1, Pin1 (bottom),
• GND- TB1, Pin6 (top), Common

5V DC for MPG encoders:

• Live - TB3 (Pin 20, +5VP)
• GND Pin23

GND between 5V DC and 12V DC is linked

I got encoders working (per attachment). If I statically set (setp) axis.x.jog-enable to True and set axis.x.jog-scale to something I can move my axis with jog wheel.
However I am not able to use switch from my MPG in case of axis / increment selection.
I tried to follow this and similar forum threads to configure my I/O on TB5 and can't get it working. I suspect some configuration / voltage issue. As you noted I am using 12V DC for Field I/O. Is it ok ? For troubleshooting purposes while switching I am watching input pins from Hal configuration (per attachment). Is this right?

I am confused as I also tried to check voltage change between common GND and eg. axis x selection switch and nothing is happening (always see 0V DC)
Per Mesa 7i76 manual , page 14 default input threshold is 50% of the field power supply voltage with10% hysteresis. Not sure if I got enough DC power for I/O so Mesa can sense it??

Please also refer to chines es axis selection switch (link to banggood) and my MPG COM is connected to Field I/O COM. I also tried to power this MPG with 5v, 12V and no difference (of course A/B/A-/B- encoders works with 5V).

Any idea, maybe you need more details to propose something?

12VDC field I/O voltage is fine

If you connect a field input to +12VDC it should read true in LinuxCNC
If you disconnect the input pin it should real false, so any input switches
must use +12VDC field power as their common, that is:

+12VDC --> SwitchT1 --> SwitchT2 --> 7I76 field input

Thank you for answer. This way I get my E Stop button working. However I am looking for a way to recognize "low, COM signal change". I tried to explain it on attached picture. As I am new to this stuff not sure if you will understand. Anyway seems Input PINs of Mesa 7i76 (revB) can sense signal change if I connect "highs, eg +5V) to them. Then if I connect GND to it signal change is recognized. However I need to connect low signals to Input PINS (COM, Normally Open)) and then if I click on switch signal should be recognized. Is it possible ?

You would not use active low but rather active high with 7I76 inputs

(so the switch COM pin connects to +12V)

You seem to have been over thinking this. COM does not mean GND.
As PCW says, connect +12v to the pendant COM wire.
Connect wires for X,Y,Z,4,5,6, x1, x10, x100 to seperate 7i76 inputs
That way as you turn the selector knobs, 12 volt will be switched to the correct input pins.

Your estop works the same way.. Its just a switch. So either you wire it in series with any other estop switches or connect one side to +12v again and the other side to the input you are using for estop. Hint: Use estop-latch for this. There is an example in the forum here.

Thank you for answers. Indeed I was over complicating this setup. Got it working and documented it https://github.com/Hortensie/CNC_x_axis_linuxcnc_mesa_5i25_7i76/blob/master/custom.hal here