HEIDENHAIN ITNC 530 - CONVERSATIONAL PROGRAMMING User Manual page 325

The following conditions are permitted in the FN 20 block:
Condition Abbreviation
Equals ==
Less than <
Greater than
>
Less than or equal <=
Greater than or equal >=
In addition, the FN20: WAIT FOR SYNC function is available. WAIT FOR
SYNC is used whenever you read, for example, system data via FN18
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
32 FN 20: WAIT FOR M4095==1
Example: Pause internal look-ahead calculation, read current
position in the X axis
32 FN 20: WAIT FOR SYNC
33 FN 18: SYSREAD Q1 = ID270 NR1 IDX1
HEIDENHAIN iTNC 530 325