How to enable screw pitch error compensation function in linuxcnc?

I have a a request, now joint0, joint1, joint2 compensation density need to be be set separately. I try a method, but it doesn't work. How to enable  screw pitch error compensation function in linuxcnc? What files need to be added?
 i add  screwcomp0.dat, screwcomp1.dat, screwcomp2.dat, and modify ini.  
my test:I tried these data as shwn figure, there is no one has a offset.

 I expect the G0 x70 can move to position 50mm and G0 x0 can move to position 10mm. 

First, I draw a line 0mm to 70mm  with a ruler. Second, i home x and open a laser on the machine and the light is on the 0mm position.  Third, send a command G0 x70. Four, watch the light position, and it is on the position 70mm.

I change the offset from 20 to 10000 in screwcomp0.data and  there is also no offset.
 
Tips, home x is OK. Linear units = mm. I think the unit of every value is mm  in screwcomp0.data.
  i add screwcomp0.dat, screwcomp1.dat, screwcomp2.dat, and modify ini.  Config/Sim/ add :screwcomp0.dat, screwcomp1.dat, screwcomp2.dat, its' content shown as figure  Config/Sim/Axis/ add :screwcomp0.dat, screwcomp1.dat, screwcomp2.dat  screwcomp0.dat content is../screwcomp0.dat  Ini add:"COMP_FILE = screwcomp0.datCOMP_FILE_TYPE = 1, "COMP_FILE = screwcomp1.datCOMP_FILE_TYPE = 1, "COMP_FILE = screwcomp2.datCOMP_FILE_TYPE = 1 [JOINT_0]TYPE = LINEARHOME = 0.000MAX_VELOCITY = 5MAX_ACCELERATION = 50.0COMP_FILE = screwcomp0.datCOMP_FILE_TYPE = 1INPUT_SCALE = 4000OUTPUT_SCALE = 1.000FERROR = 0.050MIN_FERROR = 0.010MIN_LIMIT = -10.0MAX_LIMIT = 10.0HOME_OFFSET = 0.0HOME_SEARCH_VEL = 20.0HOME_LATCH_VEL = 20.0HOME_USE_INDEX = NOHOME_IGNORE_LIMITS = NOHOME_SEQUENCE = 1HOME_IS_SHARED = 1 [JOINT_1]TYPE = LINEARHOME = 0.000MAX_VELOCITY = 5MAX_ACCELERATION = 50.0COMP_FILE = screwcomp1.datCOMP_FILE_TYPE = 1INPUT_SCALE = 4000OUTPUT_SCALE = 1.000FERROR = 0.050MIN_FERROR = 0.010MIN_LIMIT = -10.0MAX_LIMIT = 10.0HOME_OFFSET = 0.0HOME_SEARCH_VEL = 20.0HOME_LATCH_VEL = 20.0HOME_USE_INDEX = NOHOME_IGNORE_LIMITS = NOHOME_SEQUENCE = 1 [JOINT_2]TYPE = LINEARHOME = 0.0MAX_VELOCITY = 5MAX_ACCELERATION = 50.0COMP_FILE = screwcomp2.datCOMP_FILE_TYPE = 1INPUT_SCALE = 4000OUTPUT_SCALE = 1.000MIN_LIMIT = -8.0

I added these content as below:

i add screwcomp0.dat, screwcomp1.dat, screwcomp2.dat, and modify ini.

Config/Sim/ add :
screwcomp0.dat, screwcomp1.dat, screwcomp2.dat, its' content shown as figure

Config/Sim/Axis/ add :
screwcomp0.dat, screwcomp1.dat, screwcomp2.dat

screwcomp0.dat content is
../screwcomp0.dat


Ini add:
"COMP_FILE = screwcomp0.dat
COMP_FILE_TYPE = 1,

"COMP_FILE = screwcomp1.dat
COMP_FILE_TYPE = 1,

"COMP_FILE = screwcomp2.dat
COMP_FILE_TYPE = 1

[JOINT_0]
TYPE = LINEAR
HOME = 0.000
MAX_VELOCITY = 5
MAX_ACCELERATION = 50.0
COMP_FILE = screwcomp0.dat
COMP_FILE_TYPE = 1
INPUT_SCALE = 4000
OUTPUT_SCALE = 1.000
FERROR = 0.050
MIN_FERROR = 0.010
MIN_LIMIT = -10.0
MAX_LIMIT = 10.0
HOME_OFFSET = 0.0
HOME_SEARCH_VEL = 20.0
HOME_LATCH_VEL = 20.0
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = NO
HOME_SEQUENCE = 1
HOME_IS_SHARED = 1

[JOINT_1]
TYPE = LINEAR
HOME = 0.000
MAX_VELOCITY = 5
MAX_ACCELERATION = 50.0
COMP_FILE = screwcomp1.dat
COMP_FILE_TYPE = 1
INPUT_SCALE = 4000
OUTPUT_SCALE = 1.000
FERROR = 0.050
MIN_FERROR = 0.010
MIN_LIMIT = -10.0
MAX_LIMIT = 10.0
HOME_OFFSET = 0.0
HOME_SEARCH_VEL = 20.0
HOME_LATCH_VEL = 20.0
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = NO
HOME_SEQUENCE = 1

[JOINT_2]
TYPE = LINEAR
HOME = 0.0
MAX_VELOCITY = 5
MAX_ACCELERATION = 50.0
COMP_FILE = screwcomp2.dat
COMP_FILE_TYPE = 1
INPUT_SCALE = 4000
OUTPUT_SCALE = 1.000
MIN_LIMIT = -8.0

I have a request, Now joint0, joint1, joint2 compensation density need to be be set separately. I try a method, but it doesn't work. How to enable  screw pitch error compensation function in linuxcnc?What files need to be added?
 I added these content as below:  i add screwcomp0.dat, screwcomp1.dat, screwcomp2.dat, and modify ini.  Config/Sim/ add :screwcomp0.dat, screwcomp1.dat, screwcomp2.dat, its' content shown as figure  Config/Sim/screwcomp0.dat two lines content:0 10 -1070 20 -20 Config/Sim/Axis/ add :screwcomp0.dat, screwcomp1.dat, screwcomp2.dat  screwcomp0.dat content is../screwcomp0.dat  Ini add:"COMP_FILE = screwcomp0.datCOMP_FILE_TYPE = 1, "COMP_FILE = screwcomp1.datCOMP_FILE_TYPE = 1, "COMP_FILE = screwcomp2.datCOMP_FILE_TYPE = 1 [JOINT_0]TYPE = LINEARHOME = 0.000MAX_VELOCITY = 5MAX_ACCELERATION = 50.0COMP_FILE = screwcomp0.datCOMP_FILE_TYPE = 1INPUT_SCALE = 4000OUTPUT_SCALE = 1.000FERROR = 0.050MIN_FERROR = 0.010MIN_LIMIT = -10.0MAX_LIMIT = 10.0HOME_OFFSET = 0.0HOME_SEARCH_VEL = 20.0HOME_LATCH_VEL = 20.0HOME_USE_INDEX = NOHOME_IGNORE_LIMITS = NOHOME_SEQUENCE = 1HOME_IS_SHARED = 1 [JOINT_1]TYPE = LINEARHOME = 0.000MAX_VELOCITY = 5MAX_ACCELERATION = 50.0COMP_FILE = screwcomp1.datCOMP_FILE_TYPE = 1INPUT_SCALE = 4000OUTPUT_SCALE = 1.000FERROR = 0.050MIN_FERROR = 0.010MIN_LIMIT = -10.0MAX_LIMIT = 10.0HOME_OFFSET = 0.0HOME_SEARCH_VEL = 20.0HOME_LATCH_VEL = 20.0HOME_USE_INDEX = NOHOME_IGNORE_LIMITS = NOHOME_SEQUENCE = 1 [JOINT_2]TYPE = LINEARHOME = 0.0MAX_VELOCITY = 5MAX_ACCELERATION = 50.0COMP_FILE = screwcomp2.datCOMP_FILE_TYPE = 1INPUT_SCALE = 4000OUTPUT_SCALE = 1.000MIN_LIMIT = -8.0   my test:I tried these data as shwn figure, there is no one has a offset.  I expect the G0 x70 can move to position 50mm and G0 x0 can move to position 10mm.  First, I draw a line 0mm to 70mm with a ruler. Second, i home x and open a laser on the machine and the light is on the 0mm position. Third, send a command G0 x70. Four, watch the light position, and it is on the position 70mm. I change the offset from 20 to 10000 in screwcomp0.data and there is also no offset. Tips, home x is OK. Linear units = mm. I think the unit of every value is mm in screwcomp0.data.

i don't konw i can get answer from which category, so i put it in a few category.

I get your point. But that is called 'double posting' and is generally against forum etiquette as it is _very_ confusing for those who try to help. If you don't know where to put it then just put it in the 'general linuxcnc questions' section.

So that is 'quadruple' posting. That makes it a triple NO-NO.

Does anyone know about it?