Serial Connect

This function block opens and manages a serial (COM) connection. Use it to connect to serial devices, monitor connection state, and expose a connection identifier for other blocks to reference.

📥 Inputs

This function block does not have any inputs.

📤 Outputs

ConnId Unique identifier for the opened serial connection. Use this value to reference the connection from other blocks.

Connected? Boolean flag that indicates whether the serial connection is currently active.

🕹️ Controls

Port COM port name to connect to (for example COM3).

Baud Communication speed (for example 115200).

Read timeout (s) Time in seconds to wait for read operations.

Line delimiter Select the line ending used by your device (LF / CRLF / CR).

AutoReconnect Switch that enables automatic reconnection when the connection drops.

Reconnect interval (s) Interval between reconnection attempts when auto-reconnect is enabled.

Idle disconnect (s) Time of inactivity after which the connection will be closed automatically to free the port.

🎨 Features

• Automatic connection management: opens a connection with the configured parameters and keeps the ConnId available to other blocks.

• Auto-reconnect: optionally retries when the device becomes unavailable.

• Idle disconnect: closes the port when unused to avoid locking the device for other applications.

• Human-readable settings: select newline convention and tune timeouts to match the connected device.

📝 Usage Instructions

1. Set the Port and Baud values to match your device.

2. Configure Read timeout (s) and Line delimiter according to your device protocol.

3. Toggle AutoReconnect and set Reconnect interval (s) if you want the block to recover from disconnections automatically.

4. Adjust Idle disconnect (s) to let the block close the port when not in use.

5. Run the scenario. The block will open the connection and output ConnId and Connected?. Use the ConnId in other communication blocks that accept a connection reference.

📊 Evaluation

When evaluated, the block ensures a serial connection exists with the current settings. If settings change, the previous connection is released and a new one is created. The outputs reflect the active connection id and whether the connection is currently established.

💡 Tips and Tricks

• Use Led Output to visually reflect the Connected? state in your UI.

• Use String Input or Number Input and String Merge to craft commands to send over the serial link.

• Use Data Write Global / Data Read Global to share the ConnId or serial results with other parts of your scenario without direct wiring.

• Feed serial data into Data to JSON or CSV Export to log communication for later analysis.

• Forward parsed data to remote systems with MQTT Publish or REST API - Post for cloud integration or monitoring.

• Use Debug Input to inspect messages while developing your serial workflow.

• Combine with Send Mail to trigger email alerts when connection drops or when specific messages arrive.

🛠️ Troubleshooting

• If Connected? remains false: verify the device port and baud settings match the device; check device drivers and OS device manager.

• If you cannot open the port: make sure no other application is using the same COM port. Close other programs or enable idle disconnect in those systems.

• If lines appear truncated or merged: try a different Line delimiter setting or increase Read timeout (s).

• If frequent disconnects occur: enable AutoReconnect and increase Reconnect interval (s) to give the device time to recover.

• If unexpected characters appear: confirm baud rate and parity settings with the device documentation and adjust accordingly.