7 a d ditional f unctions – HEIDENHAIN TNC 640 (34059x-01) ISO programming User Manual
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Programming: Q Parameters
8.7 A
d
ditional F
unctions
The TNC 640 uses an extended interface for communication between 
the PLC and NC. This is a new, symbolic Application Programmer 
Interface (API). The familiar previous PLC-NC interface is also available 
and can be used if desired. The machine tool builder decides whether 
the new or old TNC API is used. Enter the name of the symbolic 
operand as string to wait for the defined condition of the symbolic 
operand. 
The following conditions are permitted in the D20 block:
In addition, the D20 function is available. WAIT FOR SYNC is used 
whenever you read, for example, system data via D18 that require 
synchronization with real time. The TNC stops the look-ahead 
calculation and executes the subsequent NC block only when the NC 
program has actually reached that block.
Example: Stop program run until the PLC sets marker 4095 to 1
Example: Stop program run until the PLC sets the symbolic 
operand to 1
Example: Pause internal look-ahead calculation, read current 
position in the X axis
Byte
B
0 to 4095
Word
W
0 to 2047
Double word
D
2048 to 4095
Condition
Abbreviation
Equal
==
Less than
<
Greater than
>
Less than or equal
<=
Greater than or equal
>=
N32 D20: WAIT FOR M4095==1
N32 D20: APISPIN[0].NN_SPICONTROLINPOS==1
N32 D20: WAIT FOR SYNC
N33 D18: SYSREAD Q1 = ID270 NR1 IDX1
PLC operand
Abbreviation
Address range
