Signal for safety control watchdog

Hey guys,

I am currently setting up a safety control for a milling machine, using PNOZmulti. This includes a watchdog function,
so I need a cyclical signal from linuxcnc, that I can send to the device via modbus/tcp (every 100ms/200ms/...) using MB2HAL.

Are values written every cycle so I can just set a modbus pin to 1 in my hal file?
Or are they only written if they change, so I have to use a pulse or something?

Thanks in advance

Christian

MB2HAL is a userspace component, so there is actually no guarantee that it will run at any particular frequency.

Is there any other way to keep the watchdog from biting?

I could set the watchdog timeout to a high value, like 1-10 seconds, but I don't see any other way use it.

Would you recommend using classicladder instead of mb2hal?

Hopefully someone else will chime in, I have never actually used either.

I am pretty sure that the values are written every cycle in mb2hal. (the cycle period is configured in the mb2hal.ini file) Timing is impreciseness because it isn't real time, but should be good enough for a few second watchdog.

In the config where I'm using mb2hal, I ended up disabling the watchdog in the VFD(s) because I was having too much trouble with inconstant results, because of read/write errors. I was never able to fix my communication error problem, and eventually lost interest and gave up (as it was/is working "good enough").

Ok, I think I'm going to use it like this for now.

I just started to set up mb2hal and came up with some problems. I hope you can also help me with this

As explained on linuxcnc.org/docs/html/drivers/mb2hal.html I put the line
'loadusr -w mb2hal config=MB2HAL.ini"
in my hal file and created a second ini file, called MB2HAL.ini, which is attached to this post.
The last transaction is supposed to transmit the pin for my watchdog.

So there should be some hal pins generated by mb2hal, right?
When I add show pin into the hal und open linuxcnc in the terminal, there aren't any additional pins shown.
These would be called mb2hal.15.00 for the watchdog for example if I got that right.