1. Protocol Overview

• Protocol Description: The MC 3E (MELSEC Communication Protocol 3E) is a proprietary Ethernet communication protocol developed by Mitsubishi Electric for its Q, L, and iQ-R series PLCs. The protocol supports both binary and ASCII data formats and uses TCP or UDP for transmission, enabling efficient read/write access to PLC internal data from host systems.
• Application Scenarios: This protocol is widely used in Mitsubishi automation systems and serves as a mainstream communication protocol for data exchange and equipment monitoring between PLCs and systems such as HMI, SCADA, and MES.
• E2C Trinity Support: E2C Trinity supports connecting to Mitsubishi PLCs using the MC 3E protocol via Ethernet (TCP/UDP), acting as a client to read and write data from various PLC memory areas, including X, Y, M, D, W, R, etc.

2. Prerequisites

Before starting the configuration, please ensure the following:

• Hardware Connection:
  • Ensure the E2C Trinity gateway and the target PLC are connected to the same Local Area Network (LAN) and can communicate.
  • The debugging PC must be connected to the same network to log into the E2C Trinity web interface for configuration.
• Network Parameters:
  • Obtain the IP Address and Port Number of the target PLC. The default port for the MC 3E protocol is typically 6000.
  • Ensure the E2C Trinity gateway is on the same subnet as the PLC with no IP conflicts.
• Device Parameters:
  • Prepare the PLC project file or the Data Point List.
  • Identify key parameters:
    • Communication Mode: Confirm whether the PLC is configured for TCP or UDP, and whether it uses Binary or ASCII format.
    • Data Point Addresses: e.g., D100, M200.
    • Data Type for each point: e.g., bool, short (int16), float (float32), 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.

Repeat for all tags. Once finished, click "Publish" 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 being collected.

1. 查看采集的数值是否正确

1. Test Writing: Click the edit icon in the "Latest Value" column to modify the value. The next update should reflect the change.

Common Troubleshooting (FAQ)

• Issue: Device status is "Offline" or connection failed.
  • Check physical cable connections and link lights.
  • Use the Ping tool in [System -> Tools] to check network reachability.
  • Carefully verify the IP, Port, TCP/UDP mode, and "Is Binary" settings against the PLC configuration.
  • Check PLC Ethernet module settings; ensure a connection or port is configured for the host (E2C Trinity).
• Issue: Device is connected, but tag values are null or incorrect.
  • Verify Address and Data Type: Ensure the "Address Type" (e.g., D, M), "Address" (e.g., 100), and "Data Type" (e.g., short, float) match the PLC program exactly.
  • Ensure the addressed register exists and the PLC program is running.
  • Check [Debug Logs] to filter by device and identify specific error details.
• Issue: Where to check logs?
  • Check Debug Logs or System Logs in the management interface.

5. Appendix

Mitsubishi MC 3E Data Type Mapping

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

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