Contraptor

Yes, you are right. Thank you. I forgot that part.

Thanks!

I didn't write the portion of the interface that deals with the simulation and have not changed it at all. I think the issue you are having is because the simulation code expects "full" Gcode and doesn't handle shortened forms.

This works:
G1 X1 Y1 Z1 F60.0
G1 X1 Y1 Z5.5

While this does not:
G1 X1 Y1 Z1 F60.0
G1 Z5.5

When it does work, it'll show up as colored lines being drawn in 2D showing the cutter progress.

It's one of those things that bothers me too, but it seems like way too much work to first reverse engineer how they implemented it and then fix it. I may take a crack at it in the future though.

If anyone knows of good Gcode manipulating scripts, I'd appreciate a link. I'm looking for something that can take the long form Gcode and shorten it or vice versa. Also, being able to shift all absolute points to a new origin would be handy. CamBam doesn't always put out the code in a form that I want.

I want to add a jog feature, but it'll be a while as I'm pretty busy right now. This is the perfect platform to create that type of interface too. For the time being, you can use "Enter Individual Command" box to move the tool head, or do what I did and make a physical controller. Until I found this interface, I used my controller to pause and continue my CNC. I still use it to position my machine before running code. I used a nintendo 64 controller, wired the joystick potentiometers to the Arduino analog inputs, and then added a bit of code to the Arduino.

Maybe try using a tool like cutecom ( sudo aptitude install cutecom ) and manually send Gcode to the machine to see if it works. It's better to check that that works before sending whole files of Gcode.

Thank you for the reply. As per your suggestion I loaded cutecom, I already had another serial port terminal, but I was willing to give cutecom a try. After playing around I was getting a "start" response back from the arduino and then "rs 1". After digging through the G code interpreter, rs is a check sum error on the one and only line I'm trying to send. I saw a suggest online to reduce the baud rate. I set the baud rate down to 9600 in both cutecom and the G Code Interpreter. I got the same responses. I tried to send both a file with one line of G Code and I tired typing in a single line of G code. G1 X1.0 Y0.0 Z0.0 I continue to get the checksum error and of course no movement.

Chuck

I poked in the code some more and managed to turn on the debugger. I'm sending 17 characters (the checksum's count, not mine) and it calculated 34. Makes me want to put in a divide by 2, but I'm sort of assuming that is not the correct answer.

chuck

What firmware are you using ?

Assuming you mean which G Code Interpreter, I'm not sure how to tell you without pasting the whole thing in here. There seem to be any number of them. Here are the comments plus a little bit

// Arduino G-code Interpreter
// v1.0 by Mike Ellery - initial software (moc.liamg|yrellem#moc.liamg|yrellem)
// v1.1 by Zach Hoeken - cleaned up and did lots of tweaks (moc.liamg|nekeoh#moc.liamg|nekeoh)
// v1.2 by Chris Meighan - cleanup / G2&G3 support (moc.liamg|nahgiemc#moc.liamg|nahgiemc)
// v1.3 by Zach Hoeken - added thermocouple support and multi-sample temp readings. (moc.liamg|nekeoh#moc.liamg|nekeoh)

// v1.3a mmcp - removed extruder functionality
// - changed variable array called word (!) to array called aWord
// - added sum to serial comms

// v1.4 mmcp - extended M114 to report limit switches as well as co-ordinates
//============================================================================

#define FIRMWARE_VERSION "v1.4"

#include <HardwareSerial.h>

Here is the checksum function

boolean Checksum(char instruction[], int size) {
// compute checksum
// return TRUE if ok
// return FALSE if not
//====================

int i;
int csum;
int rsum;

// start with 0
//=============
csum = 0;

// xor each byte
//==============
for (i=0; i<size; i++) {
if (instruction[i] == '*')
break;
csum = csum^instruction[i];
}

// now see if digits match checksum
//=================================
rsum = search_string('*', instruction, size);
if (rsum == csum)
return true;
else {
if (DebugLevel > 1) {
Serial.print("line: >");
Serial.print(instruction);
Serial.print("< length: ");
Serial.print(size, DEC);
Serial.print(" received: ");
Serial.print(rsum, DEC);
Serial.print(" calculated: ");
Serial.println(csum, DEC);
}
return false;
}

If that is not what you were looking for I'd be happy to provide more.

chuck

Maybe try other combination of data bits stop bits and parity in cutecom … also other baudrates … other than that I don't find anything right now …

:) Well, I think I tried most of the combinations, but I could have missed a few. I'd admit I've stuck with the 9600 baudrate. I've been looking at the checksum trying to understand how it really works. I'm also thinking the G sender code doesn't do a resend if it gets the bad checksum error. I know cutecom will ignore it. :) I started this whole project as a learning exercise. Sure didn't have checksum on my list of things to learn. :)

chuck

Looking at the code, it looks like you're supposed to send host-side checksum along with the instruction, presumably following '*' character (to be sure, need to see search_string() function):

// now see if digits match checksum
//=================================
rsum = search_string('*', instruction, size);
if (rsum == csum)
return true;
else {
//...
return false;
}

I guess the host software that goes along with this firmware computes the checksum and adds it to the line of GCode being sent.

You're 100% correct. I ended up writing my own GUI in python and I just copied the checksum generator code from the interpreter. With 20-20 hindsight I have to wonder why it took me so long to do that. As you point out the interpreter is expecting a line of G code, *, and then the checksum. The checksum is generated using the xor command. The interpreter program can send back several different strings or characters. I sends an 'ok' if all was successful. It will send back a '~' to keep the port alive while it runs the stepper motors and at the same time flash the led next to the L on the arduino at the same time. Well, that is probably more than most of you want to know. :)

chuck

Same here, I ended up writing the GUI in Processing: http://www.contraptor.org/forum/t-388209/gremote-mini-host-for-arduino-gcode-interpreter

After seeing a few serial errors on WinXP I'm now wondering if I need to add the checksum function with corresponding firmware changes. Somehow serial errors almost never happened to me with pySerial on Ubuntu. Not sure if it's the USB Serial drivers, or Java RXTXcomm..

Below is a link to a web site I created to distribute my Python script to send G code to the Arduino running the G Code Interpreter. You'll need my modified G Code Interpreter as explained on the web site.

Sorry, I guess I'm not allowed to put a link in.

chuck

Links should work, there are no restrictions as far as I know

Here is the error I receive. I'm don't think I'm a guest so I'll have to assume that I've no karma.

The data you have submitted contains following errors:

Guests and low-karma users are not allowed to publish links on this site.

chuck

It would seem I can post now. Below is a link to a web site I created where you can get a Python script to send G code to the Arduino. Having played with it for a while now I'm finding more things that need to be fixed that are annoying, but at least I can send files.

https://sites.google.com/site/chuckscncarduino/

chuck

Nice work, regarding the jog button behavior - since there is lookahead feature in the firmware, it's possible for the firmware to interpret two sequential +1s as +2. Not sure if this is what you're observing though but I thought I'd mention it.

Thank you for the nice comment. I've created a second version of the program to run a G code file from the command line. It is at the same link as I posted above.

Thanks for the tip I'll go stare at the firmware code some more as none of the other things I've tried have worked.

chuck

All, I added a Darlington transistor to activate a relay to turn the router on and off with the Arduino. It worked for awhile but then quit. After much trouble shooting I finally found that I needed to add pinMode(MOTOR_ON_PIN, OUTPUT) in the spindle_control.pde program. I have no clue why it should have ever worked without this line. I'll warn you I have not done anything more than make sure the router turns on. I've uploaded the updated modified Gcode interpreter to my website. The link is shown in my post on October 13th.

chuck