M308 max senseors not correct?

Chriss

Hi *,

I play with my "Duet 3 MB6HC MB6HC 3.5.3, Duet 3 Expansion EXP3HC EXP3HC 3.5.3 " a bit and I found that in the docu about M308:

This code replaces M305 in RepRapFirmware 3. In earlier versions of RepRapFirmware, sensors only existed in combination with heaters, which necessitated the concept of a "virtual heater" to represent a sensor with no associated heater (e.g. MCU temperature sensor). RepRapFirmware 3 allows sensors to be defined independently of heaters, up to a max of 32 sensors. The association between heaters and sensors is defined using M950.

How is it possible to use "M308 S55" when the docu speaks about "max 32 sensors?

M308 S56 P"mcu-temp" Y"mcu-temp" A"mcu"
Error: M308: Sensor number out of range
ok
M308 S56 P"mcu-temp" Y"mcu-temp" A"mcu"
ok

Do I oversee something? Or the the docu not correct? Or should I read it as "max 32 sensors per heater" and the "total max sensors" is not documented in the section?
Maybe I do simply do not get it...

Edit: And I just saw that I can not find the max fans in M950 too. :? I think that it would be nice to have the allowed range at the "Parameters" section .

Cheers, Chriss

droftarts

@Chriss See https://docs.duet3d.com/User_manual/RepRapFirmware/RepRapFirmware_overview#firmware-configuration-limits

Max sensors is 56 for Duet 3, 32 for Duet 2.
Max fans is 20 for Duet 3, 12 for Duet 2, 6 for Maestro.

Ian

chrishamm

@Chriss Board limits for heaters, sensors etc. can be checked in the limits key of the object model. I don't think it's a good idea to hard-code those values in the docs because they tend to change from time to time and per board., @droftarts perhaps it's better to refer to that key if possible?

droftarts

@chrishamm In the first para of the link I posted it says

You can check the configuration limits of the firmware version you are running by opening the 'Object Model' plugin in DWC, and checking the 'limits' section.

I think it's worth keeping the list as it helps people who are considering buying a Duet, or don't have theirs to hand.

Ian

Chriss

@droftarts Yes, yopu are right, the limit page says that. But I can remember from the top of my head that the limits are very often mentioned command sections too. Maybe the lack of consistency confused me here. I will keep an eye on it and let you know if I come across again.

Cheers, Chriss

dc42

@Chriss you are right, the M308 documentation was misleading. I have removed the reference to the maximum number of sensors being 32. Thank you for pointing this out.