HEIDENHAIN iTNC 530 HSCI Technical Manual page 1743

July 2013
Permissible entries for [value]:
Q parameter, e.g.:=Q10

Undefined:SET UNDEFINED

Q string, e.g.:=QS10

Numerical value directly, e.g.:=10

String directly, e.g.:="new value"

If you specify a Q parameter in [value], it must match the interrogated PLC
operand. The control will otherwise issue the error message Access to PLC
variable has failed.
Note
The WRITE TO PLC KEY command is run in look-ahead, meaning that the
control executes the command immediately instead of waiting until the NC
program has been executed up to the corresponding point. If a
synchronization with real time is necessary, then FN20: WAIT FOR SYNC
must be programmed in the preceding NC block. Look-ahead is then
stopped, and WRITE TO PLC KEY is not performed until this block is actually
reached in the NC program.
Note
With the FN17: SYSWRITE ID13 NR3 function, you can define a label to which
the control will jump if an error occurs executing the command. The Access
to PLC variable has failed error message will be suppressed in this case.
Examples:
WRITE TO PLC KEY "WG_ParSet_number" =+2
Writes the value 2 to WG_ParSet_number, e.g. for selecting an axis parameter
set
WRITE TO PLC KEY "MG_ParSet_activation" =+Q100
Writes the value from Q100 to the MG_ParSet_activation PLC marker, e.g. for
activating an axis parameter set
9.5 Data Transfer NC > PLC, PLC > NC
1743