M4 issues / INI Documentation / pncconf

[pcw-mesa]

It appears that M4 does not work with default pncconf created INI files and possibly with other configuration utilities due to missing ini file settings

https://forum.linuxcnc.org/24-hal-components/50076-m4-doesn-t-work

Tested on 2.9 and 2.10

The INI documentation states that the SPINDLE_X MAX_REVERSE_VELOCITY is set by default to SPINDLE_X MAX_VELOCITY, but this does not appear to be the case.

Unless MAX_REVERSE_VELOCITY is specifically set to a non-zero number in the INI file, M4 will do nothing (0 commanded speed and spindle on = false)

In addition, the spindle INI pins do not appear on the ini HAL pin list

A simple fix would be for the configuration utilities to include the missing INI tokens

[c-morley]

This seems a little deeper actually - Pncconf sets SPINDLE[0] entries for MAX_VELOCITY for say stepgens etc. There has been no work in Pncconf that I know of to incorporate new motion related spindle INI settings and it seems they clash.

A quick look in inispindle.cc seems the max_neg defaults to 0 and min_neg defaults to -1e99 - is that right?

Also min _neg and max_neg seem to be define by the opposite INI entry? https://github.com/LinuxCNC/linuxcnc/blob/master/src/emc/ini/inispindle.cc#L80

Some comments of the idea of min/max of pos/neg might help - it's almost a double negative. for instance is min_neg the lowest speed( minimum rotations ) or minimum absolute number? it's not clear enough IMHO. slowest_neg/ fastest_neg would be better descriptors I think.

I think min_neg here should actually be negative? https://github.com/LinuxCNC/linuxcnc/blob/master/src/emc/ini/inispindle.cc#L67

I would say it is a coincidence that M3 worked.

[jethornton]

This is not a Pncconf issue for sure because it affects any configuration that has a spindle section. Creating a sim config with the stepconf tool and testing without a [SPINDLE_0] section and I get:

M3 S5000 give me spindle.0.speed-out 500 and spindle.0.forward ON as expected.

M4 give me spindle.0.speed-out -500 and spindle.0.reverse ON as expected.

After removing anything from the display section that says spindle then creating a spindle section with the following:

[SPINDLE_0] MIN_VELOCITY = 0 MAX_VELOCITY = 500 INCREMENT = 500

M3 S5000 give me spindle.0.speed-out 500 and spindle.0.forward ON as expected.

M4 gives me spindle.0.speed-out 0 and spindle.0.reverse OFF which is not expected.

Adding the following to the spindle section:

MIN_REVERSE_VELOCITY = 100 MAX_REVERSE_VELOCITY = 250

And the spindle speed and direction pins respond to commands for forward and reverse as expected capping the reverse speed to -100 to -250.

Possibly this was introduced by Andy in this commit: https://github.com/LinuxCNC/linuxcnc/commit/3d005f685d5abb7928bf37be66c946acc972636e

[pcw-mesa]

So it looks like the default MAX_REVERSE_VELOCITY default setting is created from the the INI file DISPLAY section but not the SPINDLE section.

[c-morley]

[DISPLAY] settings are usually GUI related which depending on the GUI could limit any other settings (at least while in manual mode) and disguise the problem. Looking at the file I quoted, MAX_REVERSE_VELOCITY is searched in [SPINDLE_x] only

[pcw-mesa]

Right, but it looks like only the DISPLAY setting creates the default MAX_REVERSE_VELOCITY value, not the SPINDLE_X setting. Also the fact that none of the spindle settings show up in the INI hal pins made this harder to diagnose.

[andypugh]

On Mon, 18 Sept 2023 at 16:11, pcw-mesa @.***> wrote:

Right, but it looks like only the DISPLAY setting creates the default MAX_REVERSE_VELOCITY value, not the SPINDLE_X settingMessage ID: @.***>

This looks like a mistake made by me, I will try to fix it.

-- atp

[c-morley]

pull request #2659 is a fix for these problems or for discussion.

[andypugh]

Do these changes to INI variables require a change in the update_ini script? In theory, probably not, as no released version has used these (file not present in 2,8)

[c-morley]

I don't think so. The clash is fixed so default limits are set. I doubt anyone purposely set them.