Industrial Engineer · phase 6 of 16
Program / Stop Mode
Controller state used for editing or maintenance in which normal user logic and outputs are stopped or inhibited according to platform rules.
The Explain card
- Plain English
- Program mode stops the user logic. Outputs go to their configured off or fault state, the scan stops or idles, and the controller waits to be edited, downloaded to, or put back in run.
- Example
- Before a download the software asks to put the controller in program mode. The line stops, the download goes in, and the controller comes back to run when told to.
- Why it matters
- Program mode is a controlled stop and never a safe state, since outputs on some platforms hold or fail to whatever was configured. A controller in program mode looks like a dead machine to an operator, so tell people before you switch it.
- Hook
- The pause button, with everything it implies.
Where it sits in the deck
Phase 6: PLC Operating Modes, Safety, and Diagnostics
Run, program and fault: what a controller does when something goes wrong, and the safety functions that decide how much that costs.
