VERY new user

I'm an experienced Linux user but brand new to LinuxCNC. I have been using Mach on an XP CNC machine for a number of years. The Mach based system crashed and I need to move on. I'm an artist and my work can be seen here: www.howe-mccarthy.com/ The work is all 2D on a 3-axis machine (there is an A channel) controlled via a parallel port. Most of my machines are running Linux Mint 20.1 with the 5.4 Kernel.

I have a few questions:

• I have installed an old copy of LinuxCNC 2.7 but can I, or should I start with Mint 20.1 ? I'm using an old machine with an Intel Core 2 Duo E4500 / 2.2 GHz
• What is the quickest and dirtiest way of configuring my Linux setup based on the Mach setup. I've followed the documentation and LinuxCNC seems to like the stepping data file from Mach but nothing moves. Is there another file that sets up the parallel port based on the Mach configuration ?

I'm sorry that this may seem as if I'm too lazy to RTFM but I did crack it open and quickly got lost. The use of the CNC machine is rather secondary to making art, though essential. I spend most of my effort writing code for a tool that generates our G-Code.

Clive.

What do you mean by "there is an A channel"? Does that mean you have a 4th A-axis, or that you have a gantry machine with a slaved motor?

There are a number of reasons you might not have movement. First are you taking Linuxcnc out of e-stop and enabling it? (won't move until you do that.) Is Linuxcnc trying to move the motors, ie are the DROs indicating movement? Did you actually create and start a real config. or are you running a simulation? (The Stepconfig wizard, gives the option of creating a simulation config, there is a check box on the first screen.)

It's a gantry machine with a slaved motor, that's all. Nothing fancy. It is a 48" x 48" machine and so not quite a toy.

I didn't see any e-stop alert. I don't know what a DRO is. The steppers make their usual static noise. I did load an example G-Code from the installation but the machine just sits there. I would normally start with manual jogging just to check things out. It isn't clear to me how one does that in LinuxCNC. In Mach one uses the arrow keys and PgUp PgDn.

What are the LinuxCNC keyboard controls to manually move the machine?

Dear Tommy Light,
From what you write does this mean that 2.7 does NOT support joint/axis motion? Such control is essential for this machine and, to me, seems rather basic.

Here is what I have found so far: I have, apparently, installed the AXIS user interface and the arrow keys and PgUp PgDn work just as they do on Mach. The Digital Read Out values change when I press those keys. I toggle F1, F2, F3 to get manual control but nothing moves. Attached are the hal and ini files that have been converted from the Mach configuration.

In the hal file:
I can see that the x stepper uses pins 2 & 3
I can see that the y stepper uses pins 4 & 5
I can see that the z stepper uses pins 6 & 7
I can see that the a stepper uses pins 8 & 9 -- so the auxiliary fourth channel seems to be installed.
all of which seem plausible.

and the file has the axes each with:

setp stepgen.0.position-scale [AXIS_0]SCALE
setp stepgen.0.steplen 1
setp stepgen.0.stepspace 0
setp stepgen.0.dirhold 35000
setp stepgen.0.dirsetup 35000
setp stepgen.0.maxaccel [AXIS_0]STEPGEN_MAXACCEL
net xpos-cmd axis.0.motor-pos-cmd => stepgen.0.position-cmd
net xpos-fb stepgen.0.position-fb => axis.0.motor-pos-fb
net xstep <= stepgen.0.step
net xdir <= stepgen.0.dir
net xenable axis.0.amp-enable-out => stepgen.0.enable

but the ini file has no reference to:

DIRSETUP = 10000
DIRHOLD = 10000
STEPLEN = 5000
STEPSPACE = 5000

Did the translation from the Mach configuration omit something?

Clive

My internet connection to the building with my CNC machine has recently died (long story, I'm trying to restore it). So an upgrade gets messy. I'd rather burn a new 2.8 ISO and start with a fresh installation but that doesn't seem to be an option.

Can you guys confirm that 2.7 doesn't support a second stepper for the X axis? If I have no choice I shall have to haul the machine to a place where I have a wired internet connection (about a mile!). The use of a second stepper for gantry motion seems to be quite an old approach so I'm surprised if it isn't part of 2.7 -- maybe that is just how it is.

It isn't clear which section these settings belong to in the ini file.

DIRSETUP = 10000
DIRHOLD = 10000
STEPLEN = 5000
STEPSPACE = 5000

The ini file also has some weird values in this section:
[AXIS_2]
TYPE = LINEAR
HOME = 0.0
MAX_VELOCITY = 25.0
MAX_ACCELERATION = 750.0
STEPGEN_MAXACCEL = 937.5
SCALE = 40.0
FERROR = 1
MIN_FERROR = .25
MIN_LIMIT = -100.0
MAX_LIMIT = 0.001
HOME_OFFSET = 0.0

I have upgraded my 2.7 to 2.8 and both the ini and hal files have been revised. I can't tell from these files if the X and A steppers are now ganged together. Can you tell me if they are?

There is a line in the hal file that says: #This is a best-guess at the number of joints, it should be checked -- which I don't find very encouraging. If JOINT == steppers then XYZA is correct.

There is still no sign of:
DIRSETUP
DIRHOLD
STEPLEN
STEPSPACE

Looking more closely at the new documentation I suspect I need to edit
[KINS]
KINEMATICS = trivkins coordinates=XYZA
#This is a best-guess at the number of joints, it should be checked
JOINTS = 4
to
KINEMATICS = trivkins coordinates=XAYZ since the A stepper needs to be ganged to the X stepper ??
or should it be
KINEMATICS = trivkins coordinates=XYZX
or
KINEMATICS = trivkins coordinates=XXYZ kinstype=BOTH

all very confusing.