Industrial Engineer · phase 5 of 16
Implicit Messaging
CIP communication used for time-critical cyclic I/O data through an established connection.
The Explain card
- Plain English
- Implicit messaging is the scheduled, cyclic traffic that carries I/O data over CIP. The connection is set up once and then data flows at a fixed interval without anyone asking for it.
- Example
- An input block sends its sixteen bits to the controller every 10 milliseconds, and the controller sends its outputs back on the same schedule. Nobody in the program writes a read instruction.
- Why it matters
- This is the traffic that runs the machine, and it has a timeout, so a few missed packets put the device into its fault state. It is also UDP, which is fast and unacknowledged, so a noisy switch shows up as connection faults before it shows up anywhere else.
- Hook
- The data that arrives whether you ask or not.
Where it sits in the deck
Phase 5: PLC Industrial Communications
The protocols that let controllers, drives and operator panels talk, plus the addressing and description files that make them agree on what was said.
