FINS command
What Are FINS Commands?
FINS commands are the command system of OMRON's common network message service
By sending FINS commands to OMRON devices connected via Ethernet, Controller Link, Host Link and so on, you can receive the responses to the commands
Commands can also be sent to Special Units, not only CPU units
Using the network relay function, you can access across up to three network levels
This explains how to send FINS commands from a PC to a CPU unit via Ethernet
Manuals
For an explanation of FINS commands,
see the Communications Commands Reference Manual
For how to send over FINS-UDP and FINS-TCP,
see "Section 7 Creating Host Applications for FINS Communications" in the
Ethernet Unit Operation Manual (Construction of Applications)
FINS frame
| FINS header | FINS command | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ICF | RSV | GCT | DNA | DA1 | DA2 | SNA | SA1 | SA2 | SID | MRC | SRC | TEXT | |
| (Example) | 80 | 00 | 02 | 00 | 01 | 00 | 00 | 0A | 00 | 01 | |||
| FINS header | FINS command | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ICF | RSV | GCT | DNA | DA1 | DA2 | SNA | SA1 | SA2 | SID | MRC | SRC | MRES | SRES | TEXT | |
| (Example) | C0 | 00 | 02 | 00 | 0A | 00 | 00 | 01 | 00 | 01 | |||||
Parts of the FINS header that need to be changed
| ICF | 0x80 when sending | |
| RSV | Fixed 0x00 | |
| GCT | Fixed 0x02 | |
| Destination FINS address |
DNA | Destination network address (0x00 for the local network) |
| DA1 | Destination node address | |
| DA2 | Destination unit address (to the CPU = 0x00) | |
| Source FINS address |
SNA | Source network address (0x00 for the local network) |
| SA1 | Source node address (any value 01-FE that does not clash with the destination seems fine) | |
| SA2 | Source unit address (fixed 0x00) | |
| SID | Any service ID (usually a value incremented for each communication) |
FINS address
A FINS address consists of 3 bytes with the following meanings
| 1st byte | 2nd byte | 3rd byte |
|---|---|---|
| Network address | Node address | Unit address |
FINS command
| Command MRC SRC | Description | Operands |
|---|---|---|
| 0101 | Memory read | Address, number of elements |
| 0102 | Memory write | Address, number of elements, write data |
| 0103 | Fill | Address, number of elements, write data |
| 0104 | Multiple read | Multiple read addresses |
| 0401 | Start operation | MONITOR or RUN |
| 0402 | Stop operation | |
| 0501 | CPU unit information | |
| 0601 | Read CPU status | |
| 0620 | Cycle time | Initialize or read |
| 0701 | Clock read | |
| 0702 | Clock write | |
| 2101 | Error clear | Error code |
| 2102 | Error history | Start record No., number of records |
| 2103 | Error log clear |
How to specify memory types and addresses
FINS-UDP and FINS-TCP
Comparison
-
- FINS-UDP
-
- FINS-TCP
-
- Connectionless, so there is no limit on the number of connections
- Broadcast can be used
- Less reliable than TCP
Reliability drops when communicating across multi-level IP networks (e.g. the internet)- Fast
No connection procedure, so the time it takes is saved -
- Limited number of connections
- Broadcast cannot be used
- Highly reliable
Reliable even across multi-level IP networks (e.g. the internet)- Slower than UDP
The connection procedure makes processing take longer than UDP/IP- Connections can be restricted
The clients that can connect can be restricted in the server settings
-
Frame structure
Ethernet2 IP UDP FINS FCS
-
- Frame structure
Ethernet2 IP TCP FINS-TCP
headerFINS FCS
Comparison of FINS-UDP and FINS-TCP
Related pages
- FINS Message Communication
- FINS Commands
- FINS Addresses
- FINS Command Examples
- Comparison of FINS-UDP and FINS-TCP
- FinsUDP
- FinsTCP
TCP and UDP communication test tool
ComCom
An application that sends messages you create using Ethernet socket communication
FINS communication test tool
FinsMes
An application that sends FINS messages using Ethernet socket communication
FAQ
What are FINS commands?
FINS commands are the command system of OMRON's common network message service. They let you access PLCs and Special Units via Ethernet, Controller Link and other networks.
What is a FINS address?
A FINS address is a 3-byte destination identifier made up of a network address, a node address and a unit address.
What is the difference between FINS-UDP and FINS-TCP?
FINS-UDP is connectionless and fast but less reliable than TCP; FINS-TCP is connection-oriented and more reliable.
What are typical FINS commands?
Memory read (0101), memory write (0102), CPU status read (0601), clock read (0701) and so on.