Conditional Gcode: Test if key exists?

mwolter

I am attempting to make a filament load macro that detects the movement of a Duet magnetic filament monitor. Running into an issue as the "calibrated" key does not exist in the object model until a print is started.

It does not exist before print starts...

M409 K"sensors.filamentMonitors[0]"
{"key":"sensors.filamentMonitors[0]","flags":"","result":{"configured":{"mmPerRev":25.80,"percentMax":150,"percentMin":50,"sampleDistance":6.0},"enabled":true,"type":"rotatingMagnet"}}

But after it does...

M409 K"sensors.filamentMonitors[0]"
{"key":"sensors.filamentMonitors[0]","flags":"","result":{"calibrated":{"mmPerRev":27.17,"percentMax":106,"percentMin":85,"totalDistance":577.4},"configured":{"mmPerRev":25.80,"percentMax":150,"percentMin":50,"sampleDistance":6.0},"enabled":true,"type":"rotatingMagnet"}}

Before the print starts the key returns null...

M409 K"sensors.filamentMonitors[0].calibrated"
{"key":"sensors.filamentMonitors[0].calibrated","flags":"","result":null}

But if I make a macro to test for null...

if sensors.filamentMonitors[0].calibrated = null
	echo true
else 
	echo false

This is returned to the console...

M98 P"0:/macros/test"
Error: in file macro line 1 column 49: M98: cannot convert operands to same type

Should I not be comparing to null? Is there a different type?

dc42

Which firmware version are you running? My latest build gives this:

10/03/2020, 18:46:58 	echo sensors.filamentMonitors[0].calibrated = null
true

mwolter

@dc42

FIRMWARE_NAME: RepRapFirmware for Duet 2 WiFi/Ethernet FIRMWARE_VERSION: 3.01-RC3 ELECTRONICS: Duet Ethernet 1.02 or later FIRMWARE_DATE: 2020-02-29b4

dc42

If that same echo command doesn't work for you, then I guess it's fixed in the internal build ready for 3.01-RC4.

mwolter

Confirmed does not work on RC3. Will postpone this project until RC4.

3/10/2020, 2:08:10 PM	echo sensors.filamentMonitors[0].calibrated = null
Error: cannot convert operands to same type

dc42

You can try the internal build at https://www.dropbox.com/sh/3azy1njy3ayjsbp/AACquxr2m00eV568RZg5QG5wa?dl=0 if you wish - at your own risk.

mwolter

@mwolter said in Conditional Gcode: Test if key exists?:

echo sensors.filamentMonitors[0].calibrated = null

That works, thanks!