6 – 100 HEIDENHAIN Technical Manual TNC 426, TNC 430
Assigning a 
reference value
In some cases a new reference mark may have to be assigned to an axis, e.g. 
if an axis is mechanically fixed and the encoder is moved. Since due to the 
mechanical fixing the position of the axis cannot be changed, you can assign 
it a new reference value:
7
77
7 Enter the new reference value in Module 9147.
Module 9147 Assigning the reference value to an axis
If a new reference value is assigned to an axis, the corresponding bit is reset 
in W1032.
Call:
PS B/W/D/K <Axis number>
0 to 8: axes 1 to 9
PS B/W/D/K <New reference value in 0.1 µm>
CM 9147
Error recognition:
Defining the 
process of 
traversing the 
reference marks 
In machine parameters, you define the process of traversing the reference 
marks:
7
77
7 In MP1320.x and MP1330.x (for rotary encoders also in MP1331.x) you 
define the direction and velocity for traversing the reference marks.
7
77
7 In MP1340.x you define the sequence of axes for traversing the reference 
marks.
7
77
7 With MP1350.x you select the type of reference marks.
“Pass Over 
Reference Point” 
mode of operation
The NC uses W272 to report the “Pass Over Reference Point” operating 
mode to the PLC.
If you switch the operating mode before all reference marks are traversed, the 
PASS OVER REFERENCE soft key prompts you traverse the remaining 
reference marks. In W1032 the PLC receives the information as to which axes 
have not yet been referenced. 
As of NC software 280 476-03: In W1032, the bits for axes that are not to 
traverse the reference marks (MP1340.x = 0) are reset.
In the NCMACRO.SYS file, after the code word RESETINIT= you can enter the 
name (incl. path) of a macro that will be called when the Pass Over Reference 
Point mode of operation is exited. If the NC macro is terminated once with 
END PGM or M02, it will no longer be run when the Pass Over Reference 
Point mode is called and exited. 
To synchronize the current machine status and the look-ahead calculation with 
an NC macro call, (See “NCMACRO.SYS” on page 7 – 44).
Marker Value Meaning
M4203 0 No error
1 Error code in W1022
W1022 2 Invalid axis number
21 Missing strobe in M4176 = 1
24 Module was called in a spawn job or submit job