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Types of Memories |
The GE-Fanuc SNP Driver supports the memory types described on the next table.
Types of Memories
N2 or B2 Parameter |
Size |
Type of Memory |
|---|---|---|
0 |
Bit |
Discrete Inputs (%I) |
1 |
Byte |
|
2 |
Bit |
Discrete Outputs (%Q) |
3 |
Byte |
|
4 |
Bit |
Discrete Temporaries (%T) |
5 |
Byte |
|
6 |
Bit |
Discrete Internals (%M) |
7 |
Byte |
|
8 |
Bit |
%SA Discretes |
9 |
Byte |
|
10 |
Bit |
%SB Discretes |
11 |
Byte |
|
12 |
Bit |
%SC Discretes |
13 |
Byte |
|
14 |
Bit |
%S Discretes |
15 |
Byte |
|
16 |
Bit |
Genius Global Data (%G) |
17 |
Byte |
|
18 |
Word |
Analog Inputs (%AI) |
19 |
Word |
Analog Outputs (%AQ) |
20 |
Word |
Registers (%R) |
51 |
Float |
|
100-103 |
DWord |
The following DWord data types were implemented for registers:
•100: Unsigned inverted DWord
•101: Unsigned DWord
•102: Signed inverted DWord
•103: Signed DWord
DWord values are composed by 32 bits and represent 2 (two) consecutive registers on the memory of a PLC. The difference between the DWord data types refers to the order in which registers are read and how they handle signals. Inverted data types, 100 and 102, correspond to the expression (%Rn * 65536) + %Rn + 1. Normal data types, 101 and 103, correspond to the expression (%Rn + 1 * 65536) + %Rn.
For example, let's suppose that registers %R6 and %R7 store a DWord and the values in these registers are %R6 equal to 40000 and %R7 equal to 1 (one). The value returned when reading this %R6 DWord is:
•Unsigned inverted DWord: %R6 * 65536 + %R7 = 2621440001
•Unsigned normal DWord: %R7 * 65536 + %R6 = 105536
•Signed inverted DWord: %R6 * 65536 + %R7 = -1673527295
•Signed normal DWord: %R7 * 65536 + %R6 = 105536