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Variable optical attenuator function
Optical attenuators can take a number of different forms and are typically classified as fixed or variable attenuators. What's more, they can be classified as LC, SC, ST, FC, MU, E2000 etc. according to the different types of connectors. Fixed optical attenuators used in fiber optic systems may use a variety of principles for their functioning. Preferred attenuators use either doped fibers, or mis-aligned splices, or total power since both of thes.
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FB is passed as a variable to FC through the input interface
All FC parameters are passed by pointer rather than by value so it doesn't matter if it's a bool or a UDT, the processing is the same. For FB's simple variables (BOOL, INT etc. FBs and FCs receive parameters through the IN and IN/OUT interface types. When the user program passes a parameter to a. FB_init is always implicitly available and is generally called in order to perform the standard initialization (implicit call). If the explicitly defined. Both FCs and FBs are useful where a certain sequence of logic needs to be repeated and/or re-used in multiple places, but with different inputs and outputs. An example would be level control of several otherwise identical tanks, where the control algorithm involves more than a Start/Stop Circuit. Function Blocks can also use temporary variables, which exist only during a single program cycle and are not saved in the instance DB. Function Blocks are different from Functions (FC), as Functions do. A Function Block is a reusable block that can store data between scans. When calling a function block into your code you will be asked to assign a data block also called data instance to be associated with.
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