slippyr4
Posts: 10
Joined: Sat Mar 19, 2016 11:00 am

Bug in the bundled gpx restricts HBP to 120 degrees

The bundled version of gpx has a bug which caps the HBP temperature to 120 degrees, even when set higher in simplify3d (and consequently, in the generated gcode).

Can anyone (from simplify3d) say where the gpx came from? I know of 3 versions:-

The original: https://github.com/whpthomas/GPX (which has the bug)
A fork by Dan Newman: https://github.com/dcnewman/GPX (not sure if this has the bug or not)
A fork of that, by markwal: https://github.com/markwal/GPX (which has the bug fixed)
CompoundCarl
Posts: 2005
Joined: Wed Aug 05, 2015 7:23 am

Re: Bug in the bundled gpx restricts HBP to 120 degrees

I'm pretty sure the first link you posted is the original. Others are just forks from that.

And to be clear, this is NOT a bug. It is a safety feature that was specifically coded into the program. It's not an accident, it was specifically added to prevent accidentally setting the bed to a dangerous temperature. The value of 120C is specified in the file below, so you are welcome to change it and recompile if your bed can support a higher temperature
https://github.com/whpthomas/GPX/blob/master/gpx.h
slippyr4
Posts: 10
Joined: Sat Mar 19, 2016 11:00 am

Re: Bug in the bundled gpx restricts HBP to 120 degrees

Yes, I know that the first one is the original and the others are forks - but which one is shipped with Simplify3D?

However - it is a bug, and it's not a safety feature.

It's down to the firmware on the printer to restrict what is, and isn't safe - not some 3rd party tool that converts between file formats - which is all gpx is.

- The stock makerbot firmware supports a 130 degree temperature
- Sailfish firmware supports 130 degrees too
- ReplicatorG supports 130 degrees
- Makerware supports 130 degrees
- Simplify3D supports 130 degrees (from machine control panel)

According to the comments on an issue in the newest fork (https://github.com/markwal/GPX/issues/3 ) - the 120 figure is used as a cutoff to select a heater based on the temperature as a context - and 120 appears to have been used for arbitrary or historical reasons. Dan Newman, who made the comments in that link, is the maintainer of the Sailfish firmware, so is pretty authoritative on the subject.

I have built the newest of the forks from source and it works properly. However I would far rather that Simplify3D shipped with a better, working version - what will happen when I update Simplify3D since the gpx binary is stored inside the application bundle?
CompoundCarl
Posts: 2005
Joined: Wed Aug 05, 2015 7:23 am

Re: Bug in the bundled gpx restricts HBP to 120 degrees

I'm pretty sure S3D uses the original one, since I don't think those forks even existed when they first started using it.

You can always just use that same original branch and simply edit the HBP_MAX value gpx.h to 130. So you don't necessarily need a separate branch just for that change.

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