Linuxcnc 2.9.4 and Mesa 7i97T

7I97 analog outputs are generated from PWM
which requires some setup:


 ---PWM Generator signals/setup---
setp hm2_7i97.0.pwmgen.pwm_frequency 75000
setp  hm2_7i97.0.pwmgen.00.output-type 1 #PWM pin0
setp  hm2_7i97.0.pwmgen.00.offset-mode 1 # offset mode so 50% = 0
setp  hm2_7i97.0.pwmgen.00.scale  10
setp hm2_7i97.0.pwmgen.00.enable true

setp hm2_7i97.0.pwmgen.00.value 1.0


 

OK I figured it out almost
The analog pins are PWMs
But if i put this into my HAL:
setp hm2_[MESA](BOARD).0.pwmgen.00.dither true
setp hm2_[MESA](BOARD).0.pwmgen.00.output-type 1 #PWM pin0
setp hm2_[MESA](BOARD).0.pwmgen.00.offset-mode 1 # offset mode so 50% = 0
setp hm2_[MESA](BOARD).0.pwmgen.00.scale 10
setp hm2_[MESA](BOARD).0.pwmgen.00.value 1.0
I get 4.2 volt
Why? I have just double-checked 10/1 = 1

Do you get near 0V on the analog output
when the 7I97T is powered but LinuxCNC is not running?

Yes
The multimeter gave a jump to 0.5 volt in a glimpse . I don’t know for how long since the meter was set to store highest

I just tried to repeat the test.
This time the 0 was dead 0

Could it have any impact on the result that I also had the 24 v on the enable pin at the same time in the first test?

Not sure, sounds like the PWM is not setup properly

Can you run your test (where you expect 1V)

and in a terminal type

halcmd show all | grep pwm > pwm.txt

and post pwm.txt here