Chapter 3: Connect an IOC to a TCP simulator

Follow the lessons in order; keep the application source for later exercises.

• Configure StreamDevice support and two command records.
• Run a newline-delimited echo server.
• Read replies and observe connection loss and recovery.

Chapter exercises

1. Perform the simulator stop and restart exercise in lesson 3.3. Distinguish the last reply value from the command record’s alarm.
2. In the drvAsynIPPortConfigure line of st.cmd, change 9399 to an unused port. Restart the IOC and inspect the connection and write errors. Restore 9399 and confirm a successful round trip.
3. Explain which protocol writes Cmd-RB and why reading an old reply alone does not prove that the device is connected.

Before moving on

• jeonglee_Demo/ retains db/training.db, db/training.proto, and iocBoot/iocB46_182-jeonglee_Demo/st.cmd set to port 9399.
• jeonglee_Demo/simulator/ retains executable tcpserver.bash and connection_handler.sh scripts for Chapters 4 and 6.
• The jeonglee_Demo IOC is stopped with exit and tcpserver.bash is stopped with Ctrl+C.
• ss -ltn 'sport = :9399' reports no active TCP listener.