thereprapkitstore.com Prusa Mendel construction Notes/Discussions

Hi there,

Thanks for the tip, will give it a go this weekend!

hi guys, i have just recently finished build my prusa but when i plug the board in no led comes on, my pc recognises something in the usb port and it has the right drivers to make it a com port. Now when i plug in the atx power supply as well the hot end gets hot but nothing else works. i have tried to upload a new version of its firmware but it keeps coming back with various errors. is there an easy way to find out if there is still firmware on it?

also when i try to connect to it via ponterface it fails and comes up with an error and fails to connect.

I have the printer and I have connected it to pronterface , Spent a day trying to find out why the custom buttons hadn't appeared before finding that they seem to be out of date.

Now it looks as if the board is not engaging microstepping. Tabbing 0.1 on Pronterface moves the axis about 1 mm. 1 moves about 10mm 10 moves about 10 cm and 100 crashes the Max limit. (Yes, I worked out to start at max and send it down to the min endstop).

I have tried sending M92 to the software (establishes steps per unit) but it seems to be ignoring that.

On my larger drivers I have a dip switch to engage microstepping, but I cannot find any reference to switching on the Melzi microsteppers.


Do I have to reload the firmware, or is this another of those simple steps that I've managed to miss?

... it seems, you have a setting that specifies a centimeter as step size ... search for the settings to change it to 1 mm if you want mm-steps ...

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Viktor
--------
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Call for the project "garbage-free seas" - [reprap.org]

Hi There,

Thanks for your tips. Just trying to upload the sprinter firmware but to no avail. You mention a jumper to be changed o the board, which jumper is that? I also get an error message when verifying:


In file included from SdFile.cpp:20:
SdFat.h:285: error: conflicting return type specified for 'virtual void SdFile::write(uint8_t)'
C:\Documents and Settings\Marvis\Desktop\RepRapSoftware\arduino-1.0.1\hardware\sanguino\cores\arduino/Print.h:48: error: o

Not sure what needs to be done...

"is there an easy way to find out if there is still firmware on it? "

Have you got pronterface up and working? if not, download the compiled zip file from [koti.kapsi.fi] and don't bother with the python sources. (assuming you are using Windows)

Tell pronterface which port you are using, (you already have the com port driver) and make sure you set the speed in pronterface to the same as the speed in your PC control panel.

If you have got pronterface to connect (press the connect button) and get back something like
Connecting...
Sprinter
1.3.11T / 19.03.2012
start
Printer is now online.
SD Start
SD init fail
Soft PWM Init
Planner Init
Stepper Timer init
Free Ram: 480
Plan Buffer Size:1152 / 16

then send "M115" (type M115 into the bottom field on the right then press send button.)

I get back
SENDING:M115
FIRMWARE_NAME: Sprinter Experimental PROTOCOL_VERSION:1.0 MACHINE_TYPE:Mendel EXTRUDER_COUNT:1
00000000-0000-0000-0000-000000000000

Don't worry about the LED light, mine doesn't come on either.

If you aren't getting any motion then you may have to fiddle with the trim pots (see [reprap.org])

Otherwise you are about where I was when I first needed help!

ToMat,
The jumper is the one on the far right of the Melzi board.
The 2 pins need to be shorted together when you want to flash the firmware, in normal operation just hang the jumper off one of the pins to keep it from being lost.

Obviously you need a successful compile before you can try uploading the firmware.
Can't really help with the error message, I am on a Mac and it just worked. I do notice you are running Arduino v1.0... I read somewhere that that version was incompatible with our boards so I used v0.23, try that version.

Regards
Phil

Thanks for the help,

Just managed to load the firmware using arduino 023 instead of 1.01, I also selected the Sanguino board instead of the Sanguino W/MT mega 644. Once I did that it loaded without a problem and the printer is responding in pronteface. Now I know I can do it, I´ll have to investigate installing the marlin firmware which sounds better than sprinter.!

Thanks again, great forum!

"it seems, you have a setting that specifies a centimeter as step size ... search for the settings to change it to 1 mm if you want mm-steps ..."

On the Melzi, it seems that both the X and Y steppers are set to single step, without any microstepping.. The Z axis however is using X16 microsteps.

eg: from configuration.h
#define DEFAULT_AXIS_STEPS_PER_UNIT {10.0,20.423,2560,760*1.1

I have loaded the Marlin Software, using Arduino 22. After loading the Sanguino directory to the Arduino Hardware Directory, you get only the one Sanguino board to choose from.

I tried the Arduino 1.01 IDE but it threw an error each time during the compile, with the Arduino 0.22 it went through with no problem.

Printing is very lumpy. The shield around the print is made up of jagged lines with a pitch of about 1mm. There's obviously something wrong, in theory the X and Y axis are the same, yet I'm having to use 10 steps per mm in X (which is single stepping) and 20 fr the Y axis which is either a single stepping with a lot of lost steps, or just about double stepping.

Neither of which seems 'right' as most of the information I've read has shown 8 or 16 microsteps on the X and Y axis.

Anyone any ideas....or have I just got a rogue board?

Regards
Robin

"it seems, you have a setting that specifies a centimeter as step size ... search for the settings to change it to 1 mm if you want mm-steps ..."

I spent some time researching the problem. eg [www.pololu.com]

The Melzi board uses the 4988 stepper chip and this uses three resolution connector inputs MS1 MS2 MS3 to control the stepping.


MS1 MS2 MS3 Microstep Resolution
Low Low Low Full step
High Low Low Half step
Low High Low Quarter step
High High Low Eighth step
High High High Sixteenth step

Examining the board showed that the connectors marked JS4, JS5, JS6 are badly soldered, as are JS7,8 and 9. (the motors are single or half stepping, while the other connections JS10 to JS15 seem ok and teh motors are 16 stepping.

Does anyone know if these JS connectors are the equivalent of MS1,2 and 3?

(I've had no reply from the kitstore, despite their autoresponder "We will answer all emails within 24 hours").

Regards
Robin

hi all dont no if any one can help i got my kit a bout a week ago and just cant get my melzi to work ive tryed all the bit off here and just no look at all
evey time i try printrun it just says connceting its in port 3 and with 115200
i dont no alot about pcs and hex codes so iam finding it hard if any colud help
it wolud be a big big help
thxs colin
ps the wife is going nuts at me (told you so ) lol

Colin,
The speed is correct, but I think the port will be specific to your PC (I am on a MAC which assigns ports a bit differently)
Have you tried a different port from the dropdown list?

I take it you have installed Python and the associated packages ... [reprap.org]?

Are you powering the board from the USB connection, or the supplied ATX PSU? There is a jumper on the board to switch between the two. Try taking the power from the ATX PSU, your PC/laptop USB port might not be outputting enough current to power the board.


Regards
Phil

"hi all dont no if any one can help i got my kit a bout a week ago and just cant get my melzi to work ive tryed all the bit off here and just no look at all"

Go back a page (ie, your message is page 11 of this thread,look on Page 10) At the bottom of page I (Rs3) had the same sort of problem and got a useful reply.

So there's a three stage exercise for you.

1) have you installed the driver to drive the USB port as the serial port expected by the Melzi.

2) Identify the USB port being used by your computer to connect to the Melzi. The list of USB ports in use is given in Windows by accessing the system manager under control Panel and finding the USB ports in the hardware manager.

If you dont know which one is which, disconnect the melzi cable, look at the list, then reconnect the Melzi cable and see either which USB port has been identified (ie. if I disconnect the USB cable I have ports 1 to 4, when I connect the cable (through an extension bax) I get port 6. That's the port the Melzi is using.

Click on the port properties and set the speed of the port to 115200

3) Start Pronterface look under the port data and make sure it is using the same port (in my case Port 6 and the speed (115200).

Press the connect button on Pronterface, you should see a connecting message on the screen.

If there is no message, Check that the jumper in the middle of the board marked JP15 is set to use the USB and not exterior power. The jumper should occupy the two pins from the JP label (furthest away from the screw terminals). There's a post in this thread identifying the jumpers with a picture.

Regards
Robin

Hi thxs for gettin back to me
It's on com 3 and the rate is 115200
Driver is ftdi 2820
I've tryed with just the lap top and a power pack
I just keep geting connecting and if I press it again
I get could not open port 3 I've emailed the reprap kit store
And still no luck hope I've not wasted £450
On this
Do I need a new board ?

Setting up the reprapkitstore Prusa.

1) The Prusa comes with Nema 17 steppers SY42STH47-1684A

the 1684A part tells you it is a 1.68 Amp per phase stepper , 4 wires and single spindle, the B is a double spindle.

Various set-up guides tell one to set the VREF for the controller to 0.4 volts, setting the control to a maximum of 1A per phase but the pololu documentation states that setting the VREF to 0.56 V will set the controlled amps to 1.4. (it actually gives the equations so one could work it out much more accurately, but for those who need it all spelt out, setting it to 0.56 seems a lot better than setting it to 0.4 and then turning it up until the motor buzzes or something melts.)

So, is there a good reason to use 0.4V or is it simply a hangover from the author who was using 1 amp per phase steppers at the time?

2) I took the plunge and resoldered the JS connectors mentioned in a previous post. I worked and I now have micro stepping on my X and Y axis, which make for much smoother operation.

3) The next problem is that if I set the layer height to 0.25 as recommended by various posts in the thread, the first couple of layers are OK but then the hotend begins to make contact with the deposited Plastic. It's no use the machine being accurate to 0.1mm if the nozzle meets the plastic, because it promptly wobbles by up to 2mm. Either I have to adjust the extrusion rate or the layer height or mount the hot end more solidly or all three.

Still extruding
Robin

Well still no luck

Yes, all three. A combination of aluminium foil as packing and screws will hold the J Head more firmly in the socket on the extruder body. Extrusion rate calibration is very important as too much or too little plastic will ruin any chance of getting good results.

---

Using ABSPrusa Mendel Zaphod with Pronterface and slic3r 1.3.0. Printing well with 3mm PLA and ABS through 2 x J Head Mk IV b and Wade Geared Exruders. Controlled using RAMPS1.4 board running Marlin_v1.1.9

Rs3 wrote "Either I have to adjust the extrusion rate or the layer height or mount the hot end more solidly or all three. "

MotoBarsteward replied "A combination of aluminium foil as packing and screws will hold the J Head more firmly in the socket on the extruder body."

On the RRKS extruder there are two holes through the body passing through the socket into which the J Head fits. I made a simple U shaped clip from 1.6mm gas welding rod, the long arms of the U going through the holes and the base (I squared off rather than rounded the U ) lying snugly against the non-gear side. The arms go all the way through but dont touch the gear, I clipped them off flush.

When you mount the J head the bit that goes into the socket above the aluminium heat shield snugs up against these two wires exactly, the heat shield buts up against the underside of the body and there is no play in the head. No need for aluminium foil or screws, the holes could have been designed for the job. :-)

Even after ploughing Kaptan tape it is still tight.

Robin

"I've tryed with just the lap top and a power pack
I just keep geting connecting and if I press it again
I get could not open port 3 I've emailed the reprap kit store "

I'm assuming you are using some variation of Windows and know how to do basic things like turn on sounds etc.

1) When you connect the Melzi board, either by plugging in the USB cable (with the jumper set to US or with the ATX power supply by switching it on, do you get the sound that corrsponds to a new USB hardware. (I get a little two pitch ding/dong)

If you don't get the connection sound, then you are not getting a connection. This is a USB problem, not necessarily the Melzi.

When you connect other USB equipment, do you get the sound? if not, do you have the sound enabled.

This will at least tell you that the computer is recognising that you have equipment there.

2) You need to make sure that the port speed (baud rate) is set both on the Windows hardware manager and on Pronterface. I know you said you had set it, but the simple 'connecting' is a classic sign of the ports not matching. Pronterface does not select the port, you have to set the port to the port Windows is using.

3) Have you installed the Driver? I used the wrong one to start with, because I had had communications to an Arduino and assumed that that driver would do the job. It did not.

4) You haven't wasted £450 because the Melzi board is only a small part of the price. You could replace the Melzi board with another controller, there are RAMPS 1.4 boards assembled for $185 + shipping for example.

Hi thxs for getting back to me
The baud rate is set the same in the software
And port
I get the ping bog when the USB goes in
And shows up in device manager as serial com 4
And the driver is ftdi

Going to try on windows xp do u no what driver
I should use
Thx u

Edited 1 time(s). Last edit at 11/21/2012 07:48PM by colinwhyley.

I've ordered RAMPS 1.4 should be here in 4 day
Hope I can get it to work
Iam just reading up on it

Hi all got my ramps up and kind of woring but the x motor keeps going
Left and right when I press the right button
On the soft were
Any body no why ?
Thxs Colin

Endstop not registering?

Theres an endstop checking Mcode but i cannot remember what it is. Its on the main reprap wiki though. Worth investigating that.

I have not got them in yet

The endstops are often negative logic. Without the endstops in, the system will read that as the endstops being ALWAYS triggered.

Try adding them in and test it.

Additionally there is a load of settings in the firmware that can affect how the endstops work (where they are, whether they are positive or negative logic etc ...).

That sounds like classic endstop movement, it is trying to move the wrong way to clear the endstop then move back

Ok mate I will try that
Thxs for geting bk to me so fast

No problem.

This is the code for checking endstops:

[reprap.org]

If you send that from your host software, it will tell you what the printer thinks the endstops are saying.

Ok put them in and not being pick up at all

Ok well 2 stop ends work fine
But still x motor and x stop end
So that batter so far thx u clem
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