PSM Logic Functions, Logic Block Function - GF54.21-D-3210TSB

Model 447, 448 

with code ED5 (Parameterisable special module) 

with code XM7 (MOPF II) 

Model 907, 910 

with code ED5 (Parameterisable special module) 

with code XJ4 (Modification year G4-I) 

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Logic block, function 

A logic block has 4 digital inputs (E₁ , E₂ , E₃ , E₄ ) and 2 digital outputs (A_A , A_B ). The 2nd output (A_B ) is always the inversion of the 1st output (A_A ). A codable filter is connected upstream of each input (E₁ , E₂ , E₃ , E₄ ).

In one logic block, 3 2-input gates are configured according to the illustration above. These 2-input gates can perform various logic functions independently of one another. By these means, it is possible to effectively realize logic operations which for the most part consist of 2-input gates, without having to use a complete logic block each time. At the same time, there is also the option to simulate 3-input and 4-input gates with just one logic block. This procedure saves resources and shortens the throughput time of the system of the programmable logic controller (PLC) because the number of sequential logic blocks can be reduced.

One byte is made available for each logic block for determining the logic function in block X (X), block Y (Y) and block Z (Z). It has the following structure:

Coding of logic block 

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The "NAND" and "EXNOR" functions are made available by the 2nd inverted output (A_B ) of the logic system. Therefore, 2 bits suffice for coding for block Z (Z).

Signal identification number = Signal ID.

The same applies for the other logic blocks under observation of the naming conventions:

• "B < block number > _G < group number > _LB < number >..."
• "Out_G < group number > _LB < number >..."