Communications Hang

I am running Repetier host on a Mac controlling a Prusa with Gen6 (original) and Marlin.

I can set the machine up, i..e. home the axes etc. Set the temperature and print.

However sometimes when I am waiting for the machine to get up to the temp I have set at the bottom of the screen appears '1 command waiting' and after that the m/c is hung and the only way out is to disconnect and reconnect, after which it is OK until the same problem occurs.

Anyone else have a similar problem? and any ideas as to what I can try to fix it.

The console log has no extra messages etc. i.e. It does not look like the machine has reset.

Cheers
Geoff

The slicer send a blocking set temperature. So if you set 170 the firmware blocks new commands until the target temperature is finished. That's why you see the 1 commands waiting. The communication should start, when the target temperature is reached. The firmware should send temperature updates during this process.

If it is not the above reason:

An other possible reason could be a voltage drop causing problems, but that is hard to see and without heated bed that is normally no problem with a gen6. Perhaps a better USB cable could help.

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I have set Slic3r's temperature to 0, which disables using the G-Code temperature control and I set manually on the Printer Panel.

After reading some of the threads in General I am beginning to wonder if it might be an electronic noise problem on the USB comms. However, it does seem to be consistent. If I leave the machine warming up it often fails, but once up to heat it does not fail when actually printing.

It has been suggested that it could be something else in the house that is causing electrical noise. I might change PSU's and see if that helps.

Geoff

Hanging connections are always a pain. It is for a normal user not possible to detect the real reason. I don't think it is a firmware/host problem if you get it already during warmup. Could it happen at the end of the warmup? Try the temperature monitor. The firmware powers the heater with full strength at the beginning and switches to PWM near the target temperature. Some power units react slowly to larger load changes, which could be your problem. An other unit for testing could possibly show if it is the problem.

What helps is a display for the printer. There you would see if the avr itself restarts. But a restart is normally no problem. You can even press the reset button and communication continues.

The real problem arises, if the FTDI makes troubles and the most common reason is indeed electrical noise, also I never had that myself with the gen6. The reason reconnectiong works with a mac is, that the mac resets the ftdi on a new connect. If you have a windows virtual machine the behaviour could be different. There even a reconnect could be no solution. At least I had this with an other board that was very prone to noise. I needed to unplug the usb cable with windows to get it working again.

You could try the connection with a powered usb hub. Maybe it helps.

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