Reading a thermocouple ?

@andypugh

Thank you very much, with lincurve i was able to solve the problem.

If someone is interested, following the interesting HAL-lines:

Nevertheless, does someone know how to solve it using a py-script? Or is the Py-Interface not intended to do this kind of calculations?

Thanks in advance!

superman wrote: Nevertheless, does someone know how to solve it using a py-script? Or is the Py-Interface not intended to do this kind of calculations?

You could certainly write a Python userspace component to compute the temperature and make it available on a HAL pin.
linuxcnc.org/docs/2.7/html/hal/halmodule.html
But such a component does not run on a fixed realtime schedule. This means that the OS could crash and the temperature would stop updating the temperature. And this could be very bad when the temperature is that of an extruder. (one possible outcome is a house fire)
Much better to keep everything in the more dependable realtime layer.
You could do it in a C realtime component:
linuxcnc.org/docs/2.7/html/hal/comp.html
But Lincurve already exists and was designed for this sort of thing.

Hi, I tried to use max31855 component and defined following items in the hal

Before max31855 / sensor connection I got following warning (seems ok?)

However when I connect my hw/sensor to those pins I got overrun current warning at linux cnc

spi.clk.in & spi.cs.in signal are changing continuously values from 0 to 1

Any idea about root cause?
I got this Hardware piece - max31855

Connection as below, Mesa Field input is 12V

You are driving a 3.3V part with 12V signals. You have likely damaged your MAX31855.

If you want to interface to a 3.3V chip, I would suggest using the (unused)?) second I/O
port on the 5I25 (P2)

Oh well... Currently P2 is unused however I have 7i74 for long term projects to get more I/O or connet some Rs422 devices. Temporary i could use it . If i got IT right i need to set W3 up to disable 5v tolerance Mode on 5i25?? Anyway any other options like 3.3v to 12v Opto coupler or other mesa cards?

Hortensie wrote: Oh well... Currently P2 is unused

Do you have a parallel port? There is no reason you can't use that alongside a Mesa card for some extra 5V IO.