Hi Luca, Sorry for the confusion about the versions. I got confused by the fact that both versions involve a compilation step. Of course, they compile different things, but from my point of view as an integrator it is more or less the same workflow: I have a configuration file, run a compiler, and get a file that is then used by the driver.
I have now checked my setup again and I am indeed using the newer `hm2_ modbus` version with `mesambccc`, not the old `mesa_modbus`. However, from my point of view I don't really see a benefit of `hm2_modbus` over the old solution yet. It works for me, but I don't see a feature that would make me prefer it over the old driver. There is also one thing I don't like about the new version: the `mbccbs` parameter requires an absolute path to the MBCCB file. The current documentation explicitly says: https://linuxcnc.org/docs/devel/html/en/man/man9/hm2_modbus.9.html > “The path should be an absolute path to prevent nasty surprises.” For an integrator, having to put an absolute path into the INI file is rather inconvenient. It makes configurations less portable, because moving the LinuxCNC configuration directory to another machine or another user's home directory requires changing the INI file as well. There is another issue that may be worth considering before removing the old driver. The old `mesa_modbus` method is still being actively presented to users in tutorials. For example, this YouTube video demonstrates the old approach: https://www.youtube.com/watch?v=hCF-vei3s3M The problem is not that the old method exists in a tutorial, but that it isn't obvious to a user that this is now the deprecated method. Someone following that tutorial can quite reasonably end up building a new configuration with `mesa_modbus` without realizing that there is already a newer replacement. So I think that if the plan is to deprecate and eventually remove `mesa_ modbus`, it would be useful to make the migration path much more visible in the documentation and tutorials. In my particular case, though, I am already using `hm2_modbus`, so there is nothing I need to migrate. I just don't currently see a practical advantage of the new system from the integrator's perspective. Zdeněk -- S pozdravem Zdeněk Zdražil ---------- Původní e‑mail ---------- Od: Luca Toniolo <[email protected]> Komu: [email protected] Datum: 13. 8. 2026 10:04:00 Předmět: Re: [Emc-users] Deprecating the old mesa_modbus / modcompile driver "Hi Zdeně, I must have written the proposal very badly, but that is exactly what I intended to write deprecating removing mesa_modbus, is the proposal on the table. hm2_modbus already in place and replaces it, I think fully, was making sure we are not missing anything. regards, *Luca Toniolo * On 8/13/2026 3:50 PM, Zdeněk Z wrote: > Hi Luca, > > I believe the description is reversed regarding which driver is the newer > one. > > `mesa_modbus` is the **old driver**, while `hm2_modbus` is its **newer > replacement**. This was also confirmed in the discussion of PR #3819: > > * BsAtHome explicitly says that `mesa_modbus` should no longer be used and > that users should move to `hm2_modbus`: [GitHub comment by BsAtHome] > (https://github.com/LinuxCNC/linuxcnc/pull/3819?utm_source=chatgpt.com# > issuecomment-3939278576) > * In a follow-up, BsAtHome states that the old driver “has been superseded ” > and describes `hm2_modbus` as the new driver with better data mapping, data > types, translations, device initialization and timing control. > * andypugh then confirms: “Yes, mesa_modbus has been superseded, but it > still works.” [GitHub PR #3819](https://github.com/LinuxCNC/linuxcnc/pull/ > 3819?utm_source=chatgpt.com) > > So the order is: > > **`mesa_modbus` → old / superseded** > **`hm2_modbus` → newer replacement** > > Therefore, I think the proposal should be about deprecating/removing **` mesa > _modbus`**, not `hm2_modbus`. > > I was also using `mesa_modbus` while working on my configuration, which is > why I initially did not realize that it had already been superseded. > > _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users " _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
