fins.h File Reference

Omron FINS frame codec (PC_ENABLE_FINS) - zero-heap command/response builder + parser for the Factory Interface Network Service (FINS/UDP), so a device can talk to an Omron PLC over the shipped UDP transport. More...

#include "protocore_config.h"

Go to the source code of this file.

Detailed Description

Omron FINS frame codec (PC_ENABLE_FINS) - zero-heap command/response builder + parser for the Factory Interface Network Service (FINS/UDP), so a device can talk to an Omron PLC over the shipped UDP transport.

A FINS message is a 10-octet header then the command code and data:

ICF RSV GCT  DNA DA1 DA2  SNA SA1 SA2  SID   MRC SRC  [params / data...]

• ICF: bit 6 = command(0)/response(1), bit 0 = response required(0)/not(1), bit 7 = use gateway. RSV = 0, GCT = 0x02. DNA/DA1/DA2 = destination net/node/unit; SNA/SA1/SA2 = source; SID = service id (echoed in the response).
• MRC/SRC are the main/sub command code. A response inserts a 2-octet end code (MRES/SRES) before its data; MRES = SRES = 0 means normal completion.
• Multi-octet command parameters (addresses, counts) are big-endian.

FINS/UDP carries this frame directly (UDP provides integrity, so there is no checksum); FINS/TCP would prepend its own header. This is the message codec; the send is the app's.

Author

Douglas Quigg (dstroy0)

Date

2026

Definition in file fins.h.