Rockwell PLC Address Converter
Interpret classic Allen-Bradley and Rockwell PLC addresses such as N7:0, B3:1/0, T4:0.PRE, and C5:0.ACC.
Address Input
Decoded Address
⚠️ Engineering Caution:
This tool is intended for screening and pre-check workflows. Results are usually directionally useful, but they
can still shift with equipment selection, environmental conditions, naming conventions, revision status, or
interpretation rules. Confirm any value that affects ordering, substitution, compliance, or installation before
acting on it.
Frequently Asked Questions
What does B3:1/0 mean?
It typically means binary file 3, element 1, bit 0 — a bit-level address inside a classic Rockwell data table word.
Can this interpret timer and counter members?
Yes. This tool supports common timer and counter members such as PRE, ACC, EN, DN, and TT for practical address breakdowns.
What This Calculator Is For
Rockwell and Allen-Bradley PLC projects often combine several address styles that are easy to recognize once you know them, but easy to confuse during troubleshooting, migration, or documentation cleanup. Common examples include:
N7:0for integer file dataB3:1/0for bit-level access inside a binary wordT4:0.PREfor timer presetC5:0.ACCfor counter accumulated value
This tool is designed as a practical interpreter for those classic Rockwell-style addresses.
What It Calculates
The tool supports practical Rockwell address families:
- data file word style (
N,F,B) - bit-level binary style (
B3:1/0) - timer members (
T4:0.PRE,T4:0.ACC,T4:0.EN) - counter members (
C5:0.PRE,C5:0.ACC,C5:0.DN)
It converts or breaks addresses into:
- file type
- file number
- element number
- bit number when present
- structure/member field when present
- a normalized explanation of the address meaning
Core Relationships
For classic Rockwell file-based addressing:
File Numberidentifies the data table groupElement Numberidentifies the word or structure element within that fileBit Numberidentifies a bit inside a binary or status wordMemberidentifies a structure field such asPRE,ACC,EN, orDN
Examples:
N7:0→ integer file7, element0B3:1/0→ binary file3, element1, bit0T4:0.PRE→ timer file4, element0, preset member
Practical Use Cases
This tool is useful for:
- reviewing legacy SLC / MicroLogix style documentation
- converting field notes into clearer engineering references
- training technicians on Rockwell data table notation
- checking timer/counter address meaning during troubleshooting
- supporting migration planning from legacy Rockwell platforms
Important Limitations
This tool is an address interpretation helper, not a live memory browser. Real projects can still differ because of:
- controller family differences
- alias tags and symbolic addressing
- Logix tag-based systems vs file-based systems
- structure layout details not expressed in short notation
- vendor software display differences
Use it as a practical decoder for common legacy-style addresses.
FAQ
What does B3:1/0 mean?
It means binary file 3, element 1, bit 0 — typically the first bit inside word 1 of the B3 file.
What does T4:0.PRE mean?
It means timer file 4, element 0, preset member. In practice this is usually the configured preset value for that timer structure.
Is this for Logix tag names too?
This version focuses on classic file-based Rockwell notation, where practical decoding mistakes are most common.