CODESYS Features — Download and Startup

#codesys #plc #automation #industrial

Building CODESYS applications means download and start are unavoidable. This post digs one layer inward and walks the chain from compile to run.

You can also download and update from the command line without opening the CODESYS IDE.

The run chain

After the IDE compiles, you get two files:

File	What it is
`.app`	The application image: compiled target code
`.crc`	A small checksum file

Login opens the online connection, compares the application signature, and builds an online-change plan.

Download transfers the .app via the gateway protocol on port 1217, writes the image into the controller, and applies the restart policy.

Boot → Runtime services → Select boot application → Start (enter RUN).

IDE download is for the development loop. Manual update (copy .app/.crc, set boot entry, restart) is for production field updates.