S5 to S7 Marker/Flag Address Mapping: M → M
S5 to S7 marker (flag) address mapping. Addresses identical in both systems. Covers bit, byte, word, and double word access.
S5 to S7 Marker/Flag Address Mapping: M → M
Marker addresses (flags) are identical between S5 and S7. The letter M is used in both systems, in both German and English mnemonics. No conversion is needed.
Address Mapping Table
| S5 AWL | S7 STL | S7 SCL | Description |
|---|---|---|---|
| M 0.0 | M 0.0 | "Flag_0_0" | Marker bit 0.0 |
| M 100.5 | M 100.5 | "Flag_100_5" | Marker bit 100.5 |
| MB 0 | MB 0 | "FlagByte_0" | Marker byte 0 |
| MW 0 | MW 0 | "FlagWord_0" | Marker word 0 (bytes 0+1) |
| MW 100 | MW 100 | "FlagWord_100" | Marker word 100 |
| MD 0 | MD 0 | "FlagDWord_0" | Marker double word 0 |
Key Facts
- Identical in S5 and S7. M 0.0 stays M 0.0. MW 10 stays MW 10. No conversion.
- Same in DE and EN mnemonics. M is M in both languages.
- S5 "F" notation: Some S5 programs use F (Flags) instead of M. FW 0 = MW 0, FY 0 = MB 0. This F notation does not exist in S7 — replace F with M.
F-to-M Conversion (S5 only)
| S5 (F notation) | S5 (M notation) | S7 | Description |
|---|---|---|---|
| F 0.0 | M 0.0 | M 0.0 | Flag bit |
| FY 0 | MB 0 | MB 0 | Flag byte |
| FW 0 | MW 0 | MW 0 | Flag word |
| FD 0 | MD 0 | MD 0 | Flag double word |
Overlapping Access Warning
Marker areas overlap in memory. MW 0 consists of MB 0 (high byte) and MB 1 (low byte). Writing to MW 0 overwrites both MB 0 and MB 1. This behavior is identical in S5 and S7 — no migration issue, but a common source of bugs.
MW 0 = | MB 0 (high) | MB 1 (low) |
| M 0.0 ... M 0.7 | M 1.0 ... M 1.7 |
See also: Input Mapping | Output Mapping | Data Block Mapping
Part of the S5→S7 Address Mapping Reference. Maintained by PLCcheck.ai.
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