Sinumerik Alarm 12581 Channel %1 block %2 invalid read access to %3 while in motion synchronous action

Sinumerik Alarm 12581 Channel %1 block %2 invalid read access to %3 while in motion synchronous action

Parameters:
%1 = Channel number
%2 = Block number, label
%3 = Source symbol

Definitions:
In a motion synchronous action, the displayed variable must not be entered as a variable that is to be read on-line, i.e.
1. The displayed variable must not be written to the left of the comparison in a motion synchr. action. Only selected variables are permissible, e.g. WHEN $AA_OVR == 100 DO ….
2. In a motion synchronous action, the displayed variable must not be used as a $$ variable, e.g. WHEN $AA_IM[X] >= $$P_AD[1] DO … DO $AC_VC = $$P_F
3. The displayed variable must not be programmed as an online evaluated parameter of a synchronous procedure, e.g. DO SYNFCT(1, $AC_PARAM[0], $SA_OSCILL_REVERSE_POS2[Z])

Reactions:
– Alarm display.
– Interface signals are set.
– Correction block is reorganized.

Remedy:
Modify program.

Program Continuation:
Clear alarm with NC START or RESET key and continue the program.