[RRF 3.3 upgrade] G31 Error - Nozzle Crash

la_rd

Hello all,

After upgrading from RRF 3.2.2 to 3.3 I had to modify my G31 command from

G31 T4 S21 P500 X0 Y0 Z-1.3;

to

G31 S21 P500 X0 Y0 Z-1.3;

was getting a new error - something along the lines of cannot use temperature coefficient of heater -1. I unwittingly started a print anyways and this led to a nozzle crash. Turns out when that error appeared the Z-offset did not apply. 1 broken Olsson Ruby nozzle later, thought I would post a warning

This does have me thinking... it would be nice if either

A.) the Z offset always applies, even if the G31 command runs into an error

or

B.) Z offset is applied via it's own special command (is this possible already?)

oc_geek

@la_rd looks like you havn't specified the H parameter to which S temp refers to

(2) Optional parameters 'S' (temperature in °C at which the specified Z parameter is correct, default is current temperature) and 'C' (temperature coefficient of Z parameter in mm/°C, default zero) ('T' in RRF >=3.3beta2) can be set. This is useful for probes that are affected by temperature. In RRF2 the bed temperature reading is used. In RRF3 you must specify which temperature sensor to use in the H parameter.

dc42

@la_rd I'm sorry for your broken nozzle.

The reason for the problem is that the S (temperature coefficient) parameter should be used in conjunction with a T (in RRF3.3) or C (in RRF <3.3) parameter to set the coefficient, and a H parameter to select which temperature sensor to use. Your new G31 line has neither of those. That is why the command errors out.

I've added a note to change the behaviour in RRF 3.4. Most likely I will make it ignore the S parameter if no C parameter is provided, but continue to process the command.