Charge Amp Frequency

Hi, I am setting up a system that needs a 12KHz signal to trigger the charge amp circuit and I am not sure of the best method of achieving 12KHz. As I understand it LinuxCNC uses 50% of the base thread to give the charge amp frequency or I can use pwmgen to force the servo thread to 12KHz.
The question is which is the best way to turn on the charge amp?
Steve

Hi

I presume you mean charge pump?

This is the doc page www.linuxcnc.org/docs/devel/html/man/man9/charge_pump.9.html

If you cannot reduce your base thread to suit, without affecting your performance and triggering errors, you can create another thread which solely]
runs the charge pump.

See this thread for details
www.linuxcnc.org/index.php/english/forum...el-port-config#40553

(albeit in that thread the poster had the reverse problem of the charge pump frequency being too high on a low latency base thread setting)

regards

Hi

Yes it is Charge Pump

I can follow the logic of setting up a new thread to give the 12Khz signal, but I am struggling on how
to modify the ini and hal files. is it possible for you to give a clear example of what I need to do.

Steve

Hi

Yes, the second post of the thread has the hal and ini file lines I used to demonstrate the thread creation
www.linuxcnc.org/index.php/english/forum...el-port-config#40554

The speed used will not be right, you need to calculate that as shown in the doc page

EDIT - remembering that the fastest thread must be declared first

regards

Hi Sorry about being a bit slow on this, but I am starting from the ground floor with Hal. I have now read the Hal instructions and the past post now make some sense.
So to get my 12Khz signal I have included the lines given but when staring up LinuxCNC it crashes. Can someone please check over the attached .hal and .ini files
and point me in the right direction please.

Steve

addf charge-pump base-thread
probably should be
addf charge_pump base-thread

Note, its unlikely that linuxcnc crashed, it probably just aborted on a syntax error
when it does this, the offending hal line is printed (if started from a terminal)

EDIT - remembering that the fastest thread must be declared first

You have declared threads completely out of order

The names don't really matter, but the speed must increment upwards.

Use base_thread, servo_thread as the 2 fastest threads because the names are hard coded and THEN create a third slower thread.

That is what I did in the example for that very reason.
You need to substitute thread names in the hal file, but that is just a cut and paste

regards

I think these 2 files are just about right, but can't test them properly, without hacking them a lot to run as a sim, which won't be the same

See how you get on, run linuxcnc from a terminal and if you get an error, you will get the file and line number that threw it.

regards

Hi
I tried using the charge pump on the base thread at 50000us with no luck.

Tried ArcEye's Hal and ini files and I can see the errors I was making but when running LinukCNC I get the errors below.

RUN_IN_PLACE=no
LINUXCNC_DIR=
LINUXCNC_BIN_DIR=/usr/bin
LINUXCNC_TCL_DIR=/usr/lib/tcltk/linuxcnc
LINUXCNC_SCRIPT_DIR=
LINUXCNC_RTLIB_DIR=/usr/realtime-3.4-9-rtai-686-pae/modules/linuxcnc
LINUXCNC_CONFIG_DIR=
LINUXCNC_LANG_DIR=/usr/share/linuxcnc/tcl/msgs
INIVAR=inivar
HALCMD=halcmd
LINUXCNC_EMCSH=/usr/bin/wish8.5
LINUXCNC - 2.6.3
Machine configuration directory is '/home/steven/linuxcnc/configs/CP_my-mill_test'
Machine configuration file is 'CP_my-mill_test.ini'
INIFILE=/home/steven/linuxcnc/configs/CP_my-mill_test/CP_my-mill_test.ini
PARAMETER_FILE=linuxcnc.var
TASK=milltask
HALUI=halui
DISPLAY=axis
Starting LinuxCNC...
Starting LinuxCNC server program: linuxcncsvr
Loading Real Time OS, RTAPI, and HAL_LIB modules
Starting LinuxCNC IO program: io
Starting HAL User Interface program: halui
Shutting down and cleaning up LinuxCNC...
Killing task linuxcncsvr, PID=6198
Removing HAL_LIB, RTAPI, and Real Time OS modules
Removing NML shared memory segments

Debug file information:
inifile: warning: File contains DOS-style line endings.
inifile: warning: File contains DOS-style line endings.
inifile: warning: File contains DOS-style line endings.
inifile: warning: File contains DOS-style line endings.
inifile: warning: File contains DOS-style line endings.
inifile: warning: File contains DOS-style line endings.
.
inifile: warning: File contains DOS-style line endings.
inifile: warning: File contains DOS-style line endings.
inifile: warning: File contains DOS-style line endings.
Error: could not insert module /usr/realtime-3.4-9-rtai-686-pae/modules/linuxcnc/threads.ko: Unknown symbol in module
CP_my-mill_test.hal:11: exit value: 1
CP_my-mill_test.hal:11: insmod failed, returned -1
See the output of 'dmesg' for more information.
6198
PID TTY STAT TIME COMMAND
Stopping realtime threads
Unloading hal components


On the positive side I got all the mechanical parts installed on the mill and all 3 axis work well under a basic hal config

This is a very steep learning curve for me but with your help I am sure I will get to the top

Steve