FB
A functional unit in PLC programming that has an associated instance data block and must retain internal state. Its main difference from an FC (Function) is that it requires instantiation.
Timeline (last 90 days)
FB (function block) is a functional unit with background data; its difference from FC is that it needs to preserve internal state; instantiation means allocating an independent background data area for each FB call, which in 200SMART is usually embodied as one variable.
In the new version of 200SMART, all FBs need to be instantiated, and a variable must be declared in advance, otherwise the program will report an error after import because the instance cannot be found.
An FB (Function Block)'s internal static variables are stored in a separate instance data block (Instance DB); if multiple production lines share the same instance DB, timer states overwrite each other, creating a multi-instance race condition.
All Facts (3)
FB (function block) is a functional unit with background data; its difference from FC is that it needs to preserve internal state; instantiation means allocating an independent background data area for each FB call, which in 200SMART is usually embodied as one variable.
50%UnverifiedIn the new version of 200SMART, all FBs need to be instantiated, and a variable must be declared in advance, otherwise the program will report an error after import because the instance cannot be found.
50%UnverifiedAn FB (Function Block)'s internal static variables are stored in a separate instance data block (Instance DB); if multiple production lines share the same instance DB, timer states overwrite each other, creating a multi-instance race condition.
50%