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TB292 Rev2 Γ’ Installing Linear Scale for DRO Display on a CNC11 System
Using a linear scale to display DRO position with a CNC11 based Centroid CNC control
Connecting a linear scale for DRO display on an MPU11 based system running CNC11 v3 14 +
this document applies to OAK MPU11 and AllIN11DC
Scale Output Type Differential encoder output is REQUIRED Many scales are available on the market that are
not differential output Wire scale as per DB9 encoder wiring diagram in any of the MPU11 based installation
manuals In our example we used scales from http //www zsinstruments com/ specifically the GT05 450 18Γ’ for
knee and the GT05 150S slime line unit for quill ZS Instruments will configure the DB9 scale cable to match
the Centroid encoder pin out so the scale is plug and play Just be sure to specify Γ’Centroid ready cableΓ’ when
ordering
For this example we will be installing two scales on a 2 axis CNC knee mill equipped with a Centroid MPU11
based CNC control system One scale will be installed on the knee The second scale will be installed on the
quill
Configure CNC11
1 Encoder Assignment Parameters 308 thru 315 are used to tell the CNC11 software which scale is plugged
into what encoder input on the MPU11 board These parameters control which encoder the axis should look for
feedback Parameter 308 assigns the encoder to axis 1 parameter 309 assigns the encoder to axis 2 and so
on The values of these parameters can be set to any integer value from 1 thru 15 based on the table in the
operator's manual These parameters must be set before attempting to move motors Note that if you change
any of these values the machine must be powered down and restarted for the changes to take effect In our
example the encoder for the X axis is plugged into the #1 encoder input port on the MPU11 board so the value
of P308 is set to 1 the encoder for the Y axis is plugged into the #2 encoder input port on the MPU11 board so
P309 is set to 2 the scale for the knee Z axis is plugged into the #3 encoder input port on the MPU11 board so
P310 is set to 3 and the scale for the quill W axis is plugged into the #4 encoder input port so P311 is set to 4
2 Drive Assignment Parameters 300 thru 307 tell the control which drive number is actually connected for
that axis We want to make sure that the axes we use for the scale are set to 0 In our example since it's a 2
axis CNC parameter 300 is for Axis 1 X axis and 301 is for Axis 2 Y axis They are set to 1 and 2 respectively
since the X axis is installed on Axis 1 output and the Y axis is installed on Axis 2 output Since we are using Axis
3 for the knee scale and Axis 4 for the quill scale we set parameter 302 Axis 3 to 0 and parameter 303 Axis 4
to 0
3 Manual Axis Assignment Parameter 259 tells the control which axis is a manual axis by the value that it is
set to which each bit corresponds to each of the eight axes as described in the table below
Bit 0 1 2 3 4 5 6 7
Axis that is a
manual axis 1 2 3 4 5 6 7 8
Value to Add
together 1 2 4 8 16 32 64 128
A value of 1 tells the control that only the first axis is a manual axis A value of 2 tells the control that only the
second axis is a manual axis A value of 3 tells the control that the first and the second axes are manual axes
In our example Axis 3 is the knee scale and Axis 4 is the quill scale Therefore P259 = 12 4+8 which tells
CNC11 that both axes 3 and 4 are manual axes NOTE If the system was a 3 axis x y z mill CNC system with
a scale on the knee as W axis DRO P259 would be set to 8 For our example as described in step 5 we are
going to label the 3 rd
axis with the Γ’@Γ’ symbol instead of using Γ’ZΓ’ which by default makes Z a manual axis So in
our example set P259 to 8 to tell CNC11 that just the 4 th
axis W is a manual axis and if there wasn't a scale on
the knee parameter 259 would be set to 0
TB292 Rev2 Γ’ Installing Linear Scale for DRO Display on a CNC11 System
4 Axis Letter Assignment Go to the Motor Configuration menu by pressing F1 Setup F3 Config
pass=137 F2 Mach F2 Motor from the main screen
Label the axes that the scales are connected to In our example Axis 3 is Z and Axis 4 is W
Set Motor revs/inch mm/rev to 1
Set Encoder counts/rev according to the scale resolution
In our example we used a 0 0002Γ’ scale so the counts per inch = 1Γ’/ 0002Γ’ = 5000
NOTE Some scales are metric A common metric resolution is 0 05mm which relates to 5080 counts per inch
5 2 axis Operation Setup In our example the machine is a 2 axis knee mill with a manual quill The operator
is required to move the quill to the proper Z location when running a G code program CNC11 will prompt the
operator at each Z move and wait for the operator to press Cycle Start to confirm that the quill is at the proper
location before continuing with the rest of the part program Using Intercon to program 2 axis parts is the best
and easiest way Intercon will automatically generate 2 axis G code In order for Intercon to recognize that it's a
2 axis system the label in the Motor Configuration menu for the 3 rd
axis which by default is Γ’ZΓ’ will now be an Γ’@Γ’
symbol as shown below NOTE Be sure to re post any Intercon programs that were created before changing
the axis label to Γ’@Γ’
TB292 Rev2 Γ’ Installing Linear Scale for DRO Display on a CNC11 System
Notice the display on the DRO on the main screen changes from Γ’ZΓ’ to the Manual Quill Icon as shown below
Now CNC11 will prompt the operator to move the quill to the proper location during a part program
6 Edit Home File Edit the home program cncm hom to set the scale home position where ever it currently is
during homing b y adding M26/@/W as shown below
M26/@/W this sets home position where ever the scales are located when the homing sequence is run
M92/X
M26/X
M92/Y
M26/Y
TB292 Rev2 Γ’ Installing Linear Scale for DRO Display on a CNC11 System
EXTRAS
A A quick and easy way to set the Scale DRO position to 0 0000Γ’ is by mapping a spare auxiliary key on
the operator panel to run a custom M code
Parameters 188 thru 199 are used to control the behavior of the auxiliary keys on the operator panel
In our example the AUX7 key is going to call custom macro M72 which will set the DRO position of the knee
scale to 0 when it's pressed and the AUX6 key is going to call custom macro M73 which will set the DRO
position of the quill scale to 0 when it's pressed
Create a custom macro called mfunc72 mac that contains G92 @0 and one called mfunc73 mac that contains
G92 W0 Make sure to save those custom macros in the c \cncm directory
Set parameter 194 to 7211 and parameter 193 to 7311
B Customize the Part Setup menu graphics to match the scale
The default graphics used in the Centroid Part Setup menu may not match the actual machine axis
configuration In our example the Z axis is the knee scale so the default Part Setup menu graphics is fine The
quill scale we have installed is setup as a W axis The default W axis graphic in the Part Setup menu shows a
rotary table which does not match our application and is confusing to the user It is simple to create a new
graphic for the W axis and install it in the bmps directory
The Part Setup menu graphics are located in a folder named Γ’bmpsΓ’ The W axis rotary table graphics are called
mstrtneg bmp mstrtpos bmp and mstrtzro bmp Open the bmps folder and you will see them there We are
going to replace those three images with a single image showing the quill scale There are three rotary table
images since there are three ways to zero out a rotary table axis In our example we want the same quill scale
graphic to be displayed in each case so simply create a bmp bitmap image using your favorite bitmap editor
we used Photoshop that is around 600x600 pixels wide CNC11 will then scale it to the display size Name the
new bmp files mstrtneg bmp mstrtpos bmp and mstrtzro bmp and copy them into the bmps directory
overwriting the originals NOTE Making a backup of the entire bmps directory before overwriting the files is a
good idea! For our example the finished part setup graphic for the W axis looks like this
NOTE Be advised that every time you update the CNC11 software the update will overwrite your custom
images Would highly recommend making a folder outside of cncm with the custom images and after updating
the software simply copy the custom images from that folder back into the updated BMPS directory
TB292 Rev2 Γ’ Installing Linear Scale for DRO Display on a CNC11 System
Document History
Rev2 Created on 2015 04 22 by #270
Rev1 Created on 2015 03 17 by #270