Representation of the PLC function instruction

Representation of the function instruction
The expression takes the following form:

Figure 1 command basic forms

(1) [s.] is called the source operand, its content does not change with instructions, in the case of index can be used to modify the soft components, using the . symbol [s.] said the number of sources for a long time, [S1.][S2.] and so on.
(2) [d.] is called the destination operand, which change with the instructions, if you want indexing operations, and . symbols [d.] said the target number for some time, with [D1.][D2.] and so on.
(3) [n.] called the other operand, does not make the source operand, nor as a destination operand, commonly used to represent constants or as source operand or destination operand is added. Available k in decimal, hexadecimal, represented by h and d data register. Need more of these operands, the available [N1], [N2] says, if the indexing function, using the . symbol [n.]. In addition other operands available [m] to represent.