HEIDENHAIN TNC 640, User Manual, Page: 433 / 948

Programming Q Parameters | Additional functions
10
HEIDENHAIN | TNC 640 | Conversational Programming User's Manual | 10/2017
433
FN 20: WAIT FOR
– NC and PLC synchronization
NOTICE
Danger of collision!
Changes to the PLC can result in undesired behavior and
serious errors (e.g., inoperability of the control). For this reason,
access to the PLC is protected by password. The FN function
provides HEIDENHAIN as well as your machine tool builder and
suppliers the ability to communicate with the PLC from an NC
program. It is not recommended that the machine operator or
NC programmer use this. There is risk of collision during the
execution of the function and during the subsequent processing!
Only use the function in consultation with HEIDENHAIN, the
machine tool builder, or the supplier.
Comply with the documentation from HEIDENHAIN, the
machine tool builder, and suppliers.
With the
FN 20: WAIT FOR
function you can synchronize the NC
and PLC during a program run. The NC stops machining until the
condition that you have programmed in the
FN 20: WAIT FOR
block
is fulfilled.
SYNC
is used whenever you read, for example, system data via
FN 18: SYSREAD
that require synchronization with real time. The
control stops the look-ahead calculation and executes the following
NC block only when the NC program has actually reached that
block.
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