1. Protocol Overview

• Protocol Description: HostLink is a serial communication protocol developed by Omron for its PLC products, primarily used for data exchange and monitoring between host systems (such as programming software, HMI, or SCADA) and PLCs. The protocol utilizes a master-slave polling mechanism via serial ports (RS-232C or RS-485) to perform read/write operations on PLC internal memory areas (e.g., CIO, WR, HR, DM, etc.).
• Application Scenarios: The HostLink protocol is widely used for programming and monitoring Omron CP, CJ, and CS series PLCs. It is particularly common in small to medium-sized automation systems, connecting PLCs with supervisory computers or touchscreens for real-time production data monitoring and equipment status management.
• E2C Trinity Support: E2C Trinity supports the standard Omron HostLink protocol, acting as a Client to read from and write to Omron PLCs via serial communication.

2. Prerequisites

Before starting the configuration, please ensure the following:

• Hardware Connection:
  • Ensure the E2C Trinity gateway is connected to the PLC serial port (RS-232C or RS-485) using the correct wiring.
  • Verify that the baud rate, data bits, stop bits, and parity settings match the PLC communication port settings.
• Device Parameters:
  • Prepare the PLC project file or the Data Point List.
  • Identify key parameters:
    • Unit Number (HostLink Node Number): The station number of the target PLC (default is usually 0).
    • Tag Addresses: Register addresses to be collected (e.g., D100, W10.01, CIO1500).
    • Data Type: Data type for each point (e.g., int16, float32/REAL, bool, etc.).

3. Configuration Steps

Follow these steps within the E2C Trinity web interface.

Step 1: Create Device

1. Log into the gateway management page. Navigate to [Data Acquisition] to enter the E2C Trinity configuration page.

1. Click the "Create Device" button and fill in the connection information in the pop-up window.

1. Click "Save" to complete the device creation.

Step 2: Configure Tag (Point Table)

1. Select the newly created device from the device list on the left.
2. Click "Add" to create a single data acquisition Tag. Fill in the tag information.

1. Repeat the steps to add all necessary tags. Once finished, click the "Publish" button in the top right corner to apply the configuration.

4. Verification & Troubleshooting

Verification

1. Check the device list to ensure the status is Online and tags are successfully collected.

1. View the Latest Value column to verify data accuracy.

1. Test Writing: Click the edit icon in the "Latest Value" column, modify the value, and verify if the PLC accepts the change in the next polling cycle.

Common Troubleshooting (FAQ)

• Issue: Device remains offline.
  • Verify physical serial cable connections (RX/TX/GND) and ensure RS485 A/B wires are not reversed.
  • Use a serial debugging tool on a PC to confirm if the PLC is responding to standard HostLink commands.
  • Double-check serial port settings: Baud Rate, Data Bits, Stop Bits, and Parity must be identical on both sides.
• Issue: Connected, but values are null or incorrect.
  • Verify Address and Data Type: Ensure the "Address Type" and "Address" match the PLC program exactly.
  • Check [Debug Logs] to filter by device and identify specific error details (e.g., timeout, checksum error).

5. Appendix: Data Type Mapping

When configuring tags in E2C Trinity, use the following mapping:

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