The one that is really a question about which controller vendor you already own.
| PROFINET / S7 | EtherNet/IP | |
|---|---|---|
| Specification | IEC 61158/61784 (PROFINET), S7comm over ISO-on-TCP | ODVA CIP over Ethernet |
| First published | 2003 | 2001 |
| Transport | Ethernet; S7comm on TCP 102 | TCP 44818 (explicit), UDP 2222 (implicit I/O) |
| Data model | Device model defined by a GSDML file and the engineering project. S7 access is by memory area: DB numbers, byte and bit offsets. | CIP objects with classes, instances and attributes; tag-based access on Logix controllers with named, typed program tags. |
| Discovery | DCP discovery finds devices; what is *inside* a data block is defined only in the TIA project. | ListIdentity for devices; EDS files describe them. Logix tag lists are readable at runtime. |
| Security | Minimal in classic S7comm. Newer firmware adds access levels and TLS. | CIP Security exists; deployment is uneven. |
| Polling or subscription | Cyclic real-time I/O plus acyclic reads. S7comm reads are request/response. | Explicit messaging (request/response) and implicit I/O (cyclic). |
| Implementation complexity | High, and front-loaded into engineering rather than into runtime. | Moderate. Named tags make Logix far friendlier than register maps. |
| Typical industries | Siemens-centric plants: automotive, process, packaging, machine tools with 840D. | Rockwell-dominant plants: North American discrete manufacturing, material handling, packaging. |
| Forge support | Adapter shipped. 19 verticals mapped. | Adapter shipped. 19 verticals mapped. |
Strength. Deterministic cyclic I/O with real-time classes that Modbus cannot approach.
What it costs you. Tag meaning lives in an engineering project, not on the wire. Without the symbol table, DB100.DBD24 is four bytes.
PROFINET / S7 adapter →Strength. Named, typed controller tags: the semantics are at least *human* even if not standard.
What it costs you. Tag naming is a house style per integrator, so it is exactly as portable as the naming convention was disciplined.
EtherNet/IP adapter →Both are industrial Ethernet with cyclic I/O and an object or device model. The difference that matters at the data layer is naming: Logix hands you named, typed tags, while S7 hands you a byte offset into a data block. That single difference is why a Rockwell integration starts faster and a Siemens integration needs the engineering project.
Forge is not an argument for a protocol. It is the layer that makes the choice stop mattering downstream: 2,086 curated mappings across 13 protocol adapters, resolving to 985 canonical fields defined with enforced units and physics bounds.
Two devices, two protocols, two vendors, two entirely different tag names, and one canonical field out. Both of these are real mappings from the corpus, not illustrations.
Same field: part_count. Same unit contract, same physics
bounds, same shape. Your query does not need to know which protocol the reading
arrived on.