Error "plotting" simple STL

Hey all,

I seem to bump into some strange error. I have a simle STL object (1mm high square with a hole) that I wanted to use to calibrate my Darwin. Sometimes this works, sometimes it doesn't. I basically load the object and run the Produce Build. I get the following error:

Opening port /dev/ttyUSB0
Experimental: JNI_OnLoad called.
Stable Library
=========================================
Native lib Version = RXTX-2.1-7
Java lib Version = RXTX-2.1-7
RXTX Warning: Removing stale lock file. /var/lock/LCK..ttyUSB0
CAPA extruder vRefFactor set to 7
Intialising reprap
Selecting material
Setting temperature
CAPA extruder heater set to 0/0 limit 46/44
Printing warmup segments, moving to (0,5)
Printing warmup segments, printing to (0,20)
CAPA extruder re-ranging temperature (slower)
CAPA extruder vRefFactor set to 8
CAPA extruder heater set to 0/0 limit 100/96
CAPA extruder re-ranging temperature (slower)
CAPA extruder vRefFactor set to 9
CAPA extruder heater set to 0/0 limit 109/104
CAPA extruder re-ranging temperature (slower)
CAPA extruder vRefFactor set to 10
CAPA extruder heater set to 0/0 limit 238/228
Printing warmup segments, printing to (2,20)
Printing warmup segments, printing to (2,5)
java.io.IOException: Timeout receiving byte
at org.reprap.comms.snap.SNAPCommunicator.receivePacket(Unknown Source)
at org.reprap.comms.snap.SNAPCommunicator.receiveMessage(Unknown Source)
at org.reprap.comms.IncomingMessage.(Unknown Source)
at org.reprap.comms.messages.IncomingIntMessage.(Unknown Source)
at org.reprap.devices.GenericStepperMotor$RequestDDAMasterResponse.(Unknown Source)
at org.reprap.devices.GenericStepperMotor.dda(Unknown Source)
at org.reprap.devices.pseudo.LinePrinter.moveTo(Unknown Source)
at org.reprap.devices.pseudo.LinePrinter.printTo(Unknown Source)
at org.reprap.machines.Reprap.printTo(Unknown Source)
at org.reprap.geometry.Producer.produce(Unknown Source)
at org.reprap.Main$22.run(Unknown Source)
IO error/timeout, resending
Commencing layer at 0.8
java.io.IOException: Timeout receiving byte
at org.reprap.comms.snap.SNAPCommunicator.receivePacket(Unknown Source)
at org.reprap.comms.snap.SNAPCommunicator.receiveMessage(Unknown Source)
at org.reprap.comms.IncomingMessage.(Unknown Source)
at org.reprap.comms.messages.IncomingIntMessage.(Unknown Source)
at org.reprap.devices.GenericStepperMotor$RequestDDAMasterResponse.(Unknown Source)
at org.reprap.devices.GenericStepperMotor.dda(Unknown Source)
at org.reprap.devices.pseudo.LinePrinter.moveTo(Unknown Source)
at org.reprap.devices.pseudo.LinePrinter.printTo(Unknown Source)
at org.reprap.machines.Reprap.printTo(Unknown Source)
at org.reprap.geometry.LayerProducer.plot(Unknown Source)
at org.reprap.geometry.LayerProducer.plot(Unknown Source)
at org.reprap.geometry.LayerProducer.plot(Unknown Source)
at org.reprap.geometry.Producer.produce(Unknown Source)
at org.reprap.Main$22.run(Unknown Source)
IO error/timeout, resending
java.io.IOException: Timeout receiving byte
at org.reprap.comms.snap.SNAPCommunicator.receivePacket(Unknown Source)
at org.reprap.comms.snap.SNAPCommunicator.receiveMessage(Unknown Source)
at org.reprap.comms.IncomingMessage.(Unknown Source)
at org.reprap.comms.messages.IncomingIntMessage.(Unknown Source)
at org.reprap.devices.GenericStepperMotor$RequestDDAMasterResponse.(Unknown Source)
at org.reprap.devices.GenericStepperMotor.dda(Unknown Source)
at org.reprap.devices.pseudo.LinePrinter.moveTo(Unknown Source)
at org.reprap.devices.pseudo.LinePrinter.printTo(Unknown Source)
at org.reprap.machines.Reprap.printTo(Unknown Source)
at org.reprap.geometry.LayerProducer.plot(Unknown Source)
at org.reprap.geometry.LayerProducer.plot(Unknown Source)
at org.reprap.geometry.LayerProducer.plot(Unknown Source)
at org.reprap.geometry.Producer.produce(Unknown Source)
at org.reprap.Main$22.run(Unknown Source)
IO error/timeout, resending
java.io.IOException: Timeout receiving byte
at org.reprap.comms.snap.SNAPCommunicator.receivePacket(Unknown Source)
at org.reprap.comms.snap.SNAPCommunicator.receiveMessage(Unknown Source)
at org.reprap.comms.IncomingMessage.(Unknown Source)
at org.reprap.comms.messages.IncomingIntMessage.(Unknown Source)
at org.reprap.devices.GenericStepperMotor$RequestDDAMasterResponse.(Unknown Source)
at org.reprap.devices.GenericStepperMotor.dda(Unknown Source)
at org.reprap.devices.pseudo.LinePrinter.moveTo(Unknown Source)
at org.reprap.devices.pseudo.LinePrinter.printTo(Unknown Source)
at org.reprap.machines.Reprap.printTo(Unknown Source)
at org.reprap.geometry.LayerProducer.plot(Unknown Source)
at org.reprap.geometry.LayerProducer.plot(Unknown Source)
at org.reprap.geometry.LayerProducer.plot(Unknown Source)
at org.reprap.geometry.Producer.produce(Unknown Source)
at org.reprap.Main$22.run(Unknown Source)
IO error/timeout, resending
Resend limit exceeded. Failing without reported error.

Note that sometimes it goes beyond the printing warmup segment. I have also had it doing the whole build-sequence a few times after each other, and sometimes it gets this I/O exception after the warmup segment, so it starts with the first line and then this error occurs. If I wait long enough, it sometimes continues, but there might be a few minutes in between.

For the record, all the PCB's work as expected and since I am "plotting" using a pen instead of extruding, I have set the extruder temp to 20 degrees. Running Ubuntu 7.1 AMD64, Java 1.6, using a USB-> Serial converter, host software version 0.8.1 and the first firmware release (1.0).

Any hints what might cause this?

Joost van de Wiel

Edited 1 time(s). Last edit at 01/06/2008 04:24PM by Joost van de Wiel.

Well, figured out what it was. I noticed it sometimes also did not "home" when starting the Build; it seems that the micro switches I use are somehow not working properly, i.e. close the connection between the 2 pins on the PCB even when things are not near it, making the host sw think it is at it's base/home position all the time...

Joost