M
Just as an after thought on the memory retention discussion.
IEC 1131-3 offers the programmer the option of defining variables as
retained e.g.
VAR_OUT RETAIN
speed_profile:ARRAY[1..4] OF REAL;
max_speed REAL;
END_VAR
(taken from Programming Industrial Control Systems using IEC1131-3,
R.W.Lewis (IEE: ISBN 0 85296 827 2)
However, the standard (1993) (2.4.2) states that this only applies to 'warm restarts' (defined in 1131-1), all variablea are initialised to their
default value on a 'cold restart'.
I can paraphrase the text if required.
_______________________________________________
LinuxPLC mailing list
[email protected]
http://linuxplc.org/mailman/listinfo/linuxplc
IEC 1131-3 offers the programmer the option of defining variables as
retained e.g.
VAR_OUT RETAIN
speed_profile:ARRAY[1..4] OF REAL;
max_speed REAL;
END_VAR
(taken from Programming Industrial Control Systems using IEC1131-3,
R.W.Lewis (IEE: ISBN 0 85296 827 2)
However, the standard (1993) (2.4.2) states that this only applies to 'warm restarts' (defined in 1131-1), all variablea are initialised to their
default value on a 'cold restart'.
I can paraphrase the text if required.
_______________________________________________
LinuxPLC mailing list
[email protected]
http://linuxplc.org/mailman/listinfo/linuxplc