The syntax of the S7 memory addresses and the legal ranges for each of the supported PLCs are as follows:
The syntax for memory addresses takes one of 3 forms:
[Area][Byte Address].[Bit Index]
[Area][Data Size: B, W or D][Starting Byte Address]
[Data Block Number DBx].DB[Data Size: B, W, X, or D][Starting Byte Address]
|
Memory Area |
Area Prefix |
S7-200 Bytes |
S7-300 Bytes |
S7-400 Bytes |
|
Input |
E(I) |
16 (128 bits) |
8K (64Kbits) |
16K (128Kbits) |
|
Output |
A(Q) |
5 (40 bits) |
8K (64Kbits) |
16K (128Kbits) |
|
Memory |
M |
32 |
4K |
16K |
|
Special Memory |
S(SM) |
|
|
|
|
Variable Storage |
V |
|
|
|
|
Timer |
T |
512 |
1K |
4K |
|
Counter |
Z(C) |
512 |
1K |
4K |
|
Data Blocks |
DBx DBy |
|
2048, 64K each |
8192, 64K each |
|
Peripheral Input |
PE(I) |
|
|
|
|
Peripheral Output |
PA(Q) |
|
|
|
|
Analog Input |
AE(I) |
|
(n/a) |
(n/a) |
|
Analog Output |
AA(Q) |
|
(n/a) |
(n/a) |
|
Local |
L |
|
|
|