sm_modbus_tcp_relay_test_1

Test state machine for the cl_modbus_tcp_relay SMACC2 client library. This state machine exercises all relay behaviors to verify proper operation.

Overview

This state machine connects to a Waveshare 8-Channel POE ETH Relay via Modbus TCP and tests all available client behaviors:

1. CbRelayOn - Turn on a single channel
2. CbRelayOff - Turn off a single channel
3. CbAllRelaysOn - Turn on all channels
4. CbAllRelaysOff - Turn off all channels
5. CbRelayStatus - Read channel status

State Flow

StConnect ─► StConnected ─► StRelayOn ─► StRelayOff ─► StAllOn ─► StAllOff ─► StReadStatus ─► StComplete
    ▲                           │             │           │           │            │
    └───────────────────────────┴─────────────┴───────────┴───────────┴────────────┘
                              (EvConnectionLost returns to StConnect)

State Descriptions

Configuration

Edit config/sm_modbus_tcp_relay_test_1_config.yaml:

sm_modbus_tcp_relay_test_1:
  ros__parameters:
    signal_detector_loop_freq: 20

    modbus_relay:
      ip_address: "192.168.1.254"    # Your relay board IP
      port: 502                       # Modbus TCP port
      slave_id: 1                     # Modbus slave ID
      heartbeat_interval_ms: 1000     # Connection monitoring interval
      connect_on_init: true           # Auto-connect on startup

Dependencies

• cl_modbus_tcp_relay - The Modbus TCP relay client library
• smacc2 - SMACC2 framework

System Dependencies

sudo apt install libmodbus-dev

Building

# Build both packages
colcon build --packages-select cl_modbus_tcp_relay sm_modbus_tcp_relay_test_1

Running

Prerequisites

1. Ensure the relay board is powered and connected to the network
2. Verify network connectivity to the relay (default: 192.168.1.254)

Manual Connectivity Test (Optional)

Before running the state machine, you can verify connectivity with mbpoll:

# Install mbpoll if not already installed
sudo apt install mbpoll

# Test connection by reading all coil states
mbpoll -m tcp -a 1 -t 0 -r 1 -c 8 192.168.1.254

Launch the Test

source install/setup.bash
ros2 launch sm_modbus_tcp_relay_test_1 sm_modbus_tcp_relay_test_1.launch.py

Expected Output

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