Gen 3 Electronics Extruder 2.2 Issues
Posted by Skoll
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Re: Gen 3 Electronics Extruder 2.2 Issues December 17, 2010 08:08PM |
Im not sure which part of the you mean, as you have a different EC to me. but i circled in RED what i think you ment (vicktor), and circled in yellow what i think (grogyans).
adjusting the POT didnt seem to have any effect.
im starting to think it might be a comunication issue between the MB and the EC as i keep on getting the following message when the motor fails to move:
[01:06:08] Packet response code: Unknown code
[01:06:08] Packet payload: empty
adjusting the POT didnt seem to have any effect.
im starting to think it might be a comunication issue between the MB and the EC as i keep on getting the following message when the motor fails to move:
[01:06:08] Packet response code: Unknown code
[01:06:08] Packet payload: empty
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Re: Gen 3 Electronics Extruder 2.2 Issues January 19, 2011 09:27AM |
Driving a stepper with two h-bridges (and no current sensing/control) is a nasty hack, and has never worked well. All sorts of people have had problems getting it working.
You'll notice that the stepper is actually "controlled" via two extra wires running from the motherboard to the extruder controller. Have you connected these two wires? Have you connected a ground wire as well? rs-485 being a differential signaling method doesn't require the ground be exactly the same between the two boards, but the extra two wires do.
The official "stepper motor extruder using the Gen3 electronics" hack uses these two wires to control the extruder stepper, and rs-485 for fan control, temperature reporting and control, etc. The extruder controller polls the two wires, and then manipulates the h-bridges appropriately. It also checks the pot to determine what to set the PWM too. But only if it's been given the proper M-code - you can set the PWM directly via M-code, at which point it ignores the pot setting. Note that you shouldn't start with the PWM set for more than about half - one of the downsides of this hack is that it's easy to burn up the h-bridges.
It's much simpler and more reliable to add an extra stepper controller (either pololu or whatever you're already using) and hook the control wires from the motherboard (which are step and direction) to it instead, and use that to drive your extruder stepper. You'll get better control, more reliable operation, and less screwing around with a stupid hack. But you have to spend more money.
Right now I can't seem to find the info about which wires from the motherboard are step and direction, nor where to hook them up to the extruder controller. But missing the ground wire may be your problem anyway.
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I'm building it with Baling Wire
You'll notice that the stepper is actually "controlled" via two extra wires running from the motherboard to the extruder controller. Have you connected these two wires? Have you connected a ground wire as well? rs-485 being a differential signaling method doesn't require the ground be exactly the same between the two boards, but the extra two wires do.
The official "stepper motor extruder using the Gen3 electronics" hack uses these two wires to control the extruder stepper, and rs-485 for fan control, temperature reporting and control, etc. The extruder controller polls the two wires, and then manipulates the h-bridges appropriately. It also checks the pot to determine what to set the PWM too. But only if it's been given the proper M-code - you can set the PWM directly via M-code, at which point it ignores the pot setting. Note that you shouldn't start with the PWM set for more than about half - one of the downsides of this hack is that it's easy to burn up the h-bridges.
It's much simpler and more reliable to add an extra stepper controller (either pololu or whatever you're already using) and hook the control wires from the motherboard (which are step and direction) to it instead, and use that to drive your extruder stepper. You'll get better control, more reliable operation, and less screwing around with a stupid hack. But you have to spend more money.
Right now I can't seem to find the info about which wires from the motherboard are step and direction, nor where to hook them up to the extruder controller. But missing the ground wire may be your problem anyway.
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I'm building it with Baling Wire
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Re: Gen 3 Electronics Extruder 2.2 Issues January 19, 2011 09:45AM |
SDA to D10 SCL to D9
See the Mendel Wiring Diagram.
Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
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Re: Gen 3 Electronics Extruder 2.2 Issues January 19, 2011 11:20AM |
@ jgilmore
yes i think the wires are all connected correctly. but this i the first i have heard of a ground wire, and can not see one mentioned in the techzone diagrams or reprap. could you elaborate more?
i think the only option left to me is get a fourth stepper driver. and try and hook it up that way.
but the thing that bother me is i can not get it to be consistent. it either fails in one way, or a completely different way. with the condition being constant.
@ rhmorrison
it's a different board.
yes i think the wires are all connected correctly. but this i the first i have heard of a ground wire, and can not see one mentioned in the techzone diagrams or reprap. could you elaborate more?
i think the only option left to me is get a fourth stepper driver. and try and hook it up that way.
but the thing that bother me is i can not get it to be consistent. it either fails in one way, or a completely different way. with the condition being constant.
@ rhmorrison
it's a different board.
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