I have a v-core 3 and considering changing from the Duet board to Octopus v1.1 running Klipper/ Mainsail/ RatOS. My NEMA17 motors will be using 2209 drivers.
Klipper looks good except I can’t find any reference to sensorless homing and layer shift detection.
I would really like to be able to detect & send alarms on a layer shift, so wondering if it’s possible or not? If so, where can I find the documentation? Bonus question: How can a buzzer be hardwired as an alert for print start/end etc., or as an alarm when unexpected events like filament runout or layer shifts occur?
Thanks in advance!
Sensorless homing is supported provided you have the appropriate TMC stepper drivers (2209 works fine):
I’ve never seen any reference to layer shift detection in the documentation.
You should be able to run a simple piezo buzzer directly off one of the spare fan ports on the octopus. Just make sure you get a buzzer that can take 5/12/24V DC (a lot of them don’t) and run them at 100% duty cycle.
layer shift detection would be possible, with external drivers of the cl family, like the cl42 for stepper/servo nema-17 motors. I have 4 of them installed on 2 printers in the xy positions in the process of being rebuilt. I am using 4 of these motors in larger mena-23 sizes up to 3NM on cnc machinery in the garage and they are both 100% dependable, and in the event of a layer shift because of a step loss, can issue an alm signal capable of stopping linuxcnc in its tracks in 1 millisecond. Well tested, but has never happened in actual use. They have 2 other features based on the actual error being used to instantly scale the motor currant up or down according to the magnitude of the error. This results in cold motors unless its running at high speeds of over 1000 rpms for extended times measured in days. It also results in a nearly impossibly low motor noise because a lightly loaded motor is not being hammered at full current. Installing those motors has doubled the rapid speeds of a 1500 lb, 80 yo Sheldon 11x54 lathe, and made it look like its casper the ghost turning the cranks at carving metal speeds. I look fwd to having this instant stop, rehome just the xy, and resume feature in klipper. I can do it in linuxcnc by pulling the toolholder, hitting an F2 to re-power the machine, rehoming the lathe, replace the toolholder on the QC post, and resuming from the line of gcode after the one that caused the error. To reset and re-enable the errored motor presently takes a powerdown reset, which the stopping of linuxcnc does because I tie this alarm signal into the e-stop logic, toggling the F2 signal, which in turn shuts off the AC power to the machine via of big SSR’s but leaves the rpi4b running, so an F2 toggles it back on to effect the reset.
Take care and stay well.
Cheers, Gene Heskett
Actually you can but not as a direct feedback when such an event happens. See Frequently Asked Questions - Klipper documentation