M
Mark Hutton
The SFC/Grafcet is less a programming language and more a means of specifying sequences of operations. It is IMHO, beneficial as a means to
understanding ALL sequential processing (as in machine control), and is also useful in continuous control, particularly in batching (SP88), but also in higher level specification.
SFCs, to my mind can be translated to ladder (and hence to IL) and in fact many PLCs (TSX7, Omron, Mitsubishi) have special LAD or IL instructions to
allow implementation (I don't use these special instructions). For the future, a specific SFC engine could easily be written. This engine need only consist of two lists of tasks, steps and transitions, anda 'scheduler' or switcher.
-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of [email protected]
You are absolutely right. Used for some systems SFC is just great, but most systems will definitely NOT benefit from this. It heavily
depends on how the machine is working.
A traffic light is an example of something more easily programmed in SFC. An elevator is definitely more easily programmed without.
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understanding ALL sequential processing (as in machine control), and is also useful in continuous control, particularly in batching (SP88), but also in higher level specification.
SFCs, to my mind can be translated to ladder (and hence to IL) and in fact many PLCs (TSX7, Omron, Mitsubishi) have special LAD or IL instructions to
allow implementation (I don't use these special instructions). For the future, a specific SFC engine could easily be written. This engine need only consist of two lists of tasks, steps and transitions, anda 'scheduler' or switcher.
-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of [email protected]
You are absolutely right. Used for some systems SFC is just great, but most systems will definitely NOT benefit from this. It heavily
depends on how the machine is working.
A traffic light is an example of something more easily programmed in SFC. An elevator is definitely more easily programmed without.
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LinuxPLC mailing list
[email protected]
http://linuxplc.org/mailman/listinfo/linuxplc