@dc42 I have a suggestion for making things much simpler and not further complicating RRF GCODE.

We basically need M3, M4 and M5 commands to handle the spindle at the GCODE level, plus M950 to init the corresponding io.

As far as I understand, these commands, handle a spindle created with M950, which, in turn make the assumption we drive the spindle by pwm through a given pin. Nothing is related to modbus nor serial link in M950. This command is somewhat complex, because you handle many different peripherals (led strip,PWM, servo, temp, etc), everything that can be handled by DUET standard io at the hardware level.

As you said, there is little chance that you can support each and every modbus motor/controller on the market, and this should be the case, I think the program memory should be filled by unused code.

On the other hand, a GCODE command not implemented in RRF will call a macro of the same name ( e.g. M1000.g)
We could use a M3.1 M4.1 M5.1 to handle the modbus specific, but this would not be standard and would need some post processing.

I suggest that RRF, for limited control codes (M3,M4,M5...), instead of handling what is defined by M950, just call corresponding macros when instructed by M950.

This way, M3,M4,M5 would be handled by the user, it's the user's responsibility to handle all the modbus specifics inside these macros.

Introduce a parameter M (0 or 1, default 0) in M950 that tells, for the corresponding spindle (R parameter), to call M3_R.g, M4_R.g, M5_R.g R being the spindle number. To avoid a race condition, M3,M4,M5 commands called from inside these macros should not be possible, either raise an error or just do nothing.

modbus complexity would then be handled by a macro.

you can extend this to other devices (fans, heater, leds,....) managed through serial, spi or I2C devices.

M3 P1 S1000 would call the macro M3_1.g with parameter S=1000 exactly like M98 P"M3_1.g" S1000.
M950 with the M1 and R1 would also call a macro M950_1.g that would init the serial link, maybe check the modbus status to make sure it will work.

You could expand this to all codes related to M950 for handling special cases not handled by DUET ios.

I think it would solve the issues I have seen on the forum, included mine without introducing specific GCODES.

Bought a Fabtotum on Kickstarter, received it in 2015, and got my 3D Printing training with it. Good training, since it learned me by practice all the mistakes to avoid as a user, but also all those to avoid as a designer.
For instance, it stopped using it after the ribbon broke due to trailing on the bed and colliding with printing part. Collecting dust since 2 years since.

I decided recently to give it a rebirth by changing almost everything except COREXY mechanic, the most valuable thing in FT in my view.

Removed all guts, including the RPI and heads, printed parts for X end stop, new bowden E3D V6 / TITAN based with most advanced parts, and it worked almost at the 1st run.
I will now use this as a test platform for new heads, water cooled, TITAN direct drive and more.

@fcwilt Yes, I print tiny parts ( custom gears and connectors), and I need minimal entry points on my objects to allow best external mechanical interface possible.

Therefore I need to purge my nozzle between each part to ensure identical start conditions.

And since I need many parts, I stuff my printing bed with as much as possible parts.

@NineMile I have seen this thread , did not find him again , however this was in a corner of my memory for a while.
I am refurbishing a Roland CAMM 3 trying to keep the control panel with 3 separate x y z jogs.

Will test happily your work as soon the old panel is connected to the Duet6HC through a custom made board I am working on.

@dc42 I don't plan to, I just need to calculate and adjust the rpm from a tick sensor on spindle start.
I use a biffy BLDC that transmit movement to an ER16 spindle through a set of GT2 pulleys.

@NineMile Nothing prevent M568 to be treated like M3...4.. 5, since the spindle number should be used the same way.

@dc42 I have a suggestion for making things much simpler and not further complicating RRF GCODE.

We basically need M3, M4 and M5 commands to handle the spindle at the GCODE level, plus M950 to init the corresponding io.

As far as I understand, these commands, handle a spindle created with M950, which, in turn make the assumption we drive the spindle by pwm through a given pin. Nothing is related to modbus nor serial link in M950. This command is somewhat complex, because you handle many different peripherals (led strip,PWM, servo, temp, etc), everything that can be handled by DUET standard io at the hardware level.

As you said, there is little chance that you can support each and every modbus motor/controller on the market, and this should be the case, I think the program memory should be filled by unused code.

On the other hand, a GCODE command not implemented in RRF will call a macro of the same name ( e.g. M1000.g)
We could use a M3.1 M4.1 M5.1 to handle the modbus specific, but this would not be standard and would need some post processing.

I suggest that RRF, for limited control codes (M3,M4,M5...), instead of handling what is defined by M950, just call corresponding macros when instructed by M950.

This way, M3,M4,M5 would be handled by the user, it's the user's responsibility to handle all the modbus specifics inside these macros.

Introduce a parameter M (0 or 1, default 0) in M950 that tells, for the corresponding spindle (R parameter), to call M3_R.g, M4_R.g, M5_R.g R being the spindle number. To avoid a race condition, M3,M4,M5 commands called from inside these macros should not be possible, either raise an error or just do nothing.

modbus complexity would then be handled by a macro.

you can extend this to other devices (fans, heater, leds,....) managed through serial, spi or I2C devices.

M3 P1 S1000 would call the macro M3_1.g with parameter S=1000 exactly like M98 P"M3_1.g" S1000.
M950 with the M1 and R1 would also call a macro M950_1.g that would init the serial link, maybe check the modbus status to make sure it will work.

You could expand this to all codes related to M950 for handling special cases not handled by DUET ios.

I think it would solve the issues I have seen on the forum, included mine without introducing specific GCODES.

@dc42 I did change the power to 5V and this is OK now.
Many thanks

@dc42 Saleae logic is connected to the io1 pins.
Converter is powered by DUET 3.3v line.
Will test 5v supply to the converter and report.

Thanks

@dc42 Here is a complete test sequence

M260.4 P2 A1 B{0x06,0x80,0x05,0xdc,0x05} R5 Note:works with coma separating bytes, not with ':' as separator

The message is processed, then spindle speed is set correct accordingly.
Note the glitches in the yellow trace during device answer, they are not systematic, but frequent.

M260.1 P2 A1 F6 R{0x8005} B{0xdc05}
Message is processed, then spindle speed is set correct accordingly.
Answering time is randomly different, according to mpdbus specs..
Note the glitches on DUET's yellow trace.

In both cases, same error

I can live with that until further notice, since errors only pollute the UI and this is workable for now.

If you have more test sequences in mind, will be happy to help with my setup:

1-Stepperonline BLD-530 S coupled to a biffy BLDC
2-Waveshare TTL To RS485 (C) Galvanic Isolated Converter, Half-Duplex Communication, Lightningproof & Anti-Surge, Multi-Isolation Protection
SKU: 27479
Part Number: TTL TO RS485 (C)
3-DUET 6HC under 48V power supply in CNC mode

Thanks for help

@droftarts Works now writing a single register with betaversion from @dc41 excepts that it always say
"Error: M260.1: no or bad response from Modbus device"

DUET issues a single register write

device's answer in green

These answers are analyzed by Saleae Logic analyzer.

The only difference is the device seem to answers with a larger stop bit, while DUET is perfectly
OK on timing.

Since I cannot dig more into the error above, I cannot determine what is wrong or if this is just due to beta version.

DUET3 6HC 3.6.0-beta.2 CNC mode

Trying to communicate with a StepperOnline BLD-530S BLDC Motor controller in modbus (spindle).

Try to send raw modbus message as indicated in the BLD-530S user manual, get this answer....

Error: M260.4: Command is not supported

260.1 works but not understandable by BLD-530-S (reason why I try M260.4)

Any idea of availability? 3.6.0-beta.3? official release? when?

Many thanks

Kind Regards

Quick questions regarding 3.6.0 Beta.2 on a DUET6HC

Are the M260.1/M260.2 commands available on this beta version as stated in the doc ?

If YES: May I use simulateously
1-DuetWebControl through wifi for console operation
2-io0 serial IO connected t to a custom CNC-Pendant like board
3-io1 serial IO connected to an adapter talking to a modbus device (BLDC controller)

io0:I would send gcode command (M105, M409.... GXXX) through io0

io1:General idea is to keep spindle section electically isolated from DUET to avoid mass loops, since currents (both DUET 48V with NEMA23) and 400W BLDC are pretty high and cabling is quite complex, while having complete gcode control over BLDC (speed, CW/CCW, stall ....)

What is the max baud rate for each interface when used ?

is there any bottleneck/precaution to use this somewhat serial IO demanding configuration?

Of course I will carefully test all this and report any issue and/or success.

If NO or partially available, how long will I have to wait (project planning, I have no killing deadline ) ?

Many thanks for your help