Melsec TCP/UDP (Mitsubishi)
Melsec TCP/UDP (Ethernet)
The Melsec TCP and UDP drivers are used to communicate with Mitsubishi Electric PLCs such as the Q, L, FX5U, and iQ-R series over the Ethernet port.
These drivers use Mitsubishi’s standard MC Protocol (3E Frame) communication structure.
Connection Settings (Network Settings)
When you select the protocol name in the tree view, these settings define the network parameters of the PLC.
| Parameter | Description | Example |
| Ethernet Adapter | Selects which network adapter on your computer will be used. If All is selected, Windows’ default routing is used. | All |
| IP Address | The IP address of the Mitsubishi PLC to connect to. | 192.168.0.10 |
| Port | MC Protocol communication port. • For TCP, common defaults are 5007 or 5002. • For UDP, common defaults are 5000 or 5001. (Should be checked in the PLC project under Built-in Ethernet Port Settings.) | 5000 |
| Network No | Network Number: The network ID where the target PLC resides. Typically 0 for direct connections. (If not routing through CC-Link IE, keep it as 0.) | 0 |
| PC No | Station Number: The number of the target PLC on the network. 255 (0xFF) means “the station I am directly connected to” and is commonly used. | 255 |
| Module No | CPU Number: Selects which processor to connect to in a Multi-CPU system. Use 0 for standard single-CPU systems. | 0 |
| IO No | Ethernet Module I/O Address: The I/O address of the Ethernet port on the PLC. • 1023 (0x3FF): Typically the built-in Ethernet port on the CPU. • For external Ethernet modules (e.g., QJ71E71), this value depends on the module slot. | 1023 |
| Delay (ms) | Minimum waiting time between two communication requests. | 100 |
| Timeout (ms) | Maximum waiting time for a PLC response after a request is sent. | 250 |
| Retry Count | Number of retry attempts before entering the Fault state if communication errors occur. | 3 |
Station (Device) Settings
In Mitsubishi MC Protocol, the device is defined using the PC Number and Network Number.
| Parameter | Description |
| Address | PC Number (Network Station): • For direct CPU connection, 255 (0xFF) or 1 is commonly used. • If accessing another station in a Mitsubishi network (e.g., CC-Link IE), enter that station’s number. |
| Symbol | Symbolic name assigned to the device (e.g., Device). |
| Enable | Determines whether the device is active. Conditions can be defined to dynamically enable or disable communication. Multiple conditions may be assigned; if any is true, the device becomes active. Leave blank to keep the device always active. |
| Maximum word count | Packet Size: Maximum number of Words (Registers) to read at once. Default is 125. Note: For older FX series PLCs or noisy lines, reducing this value (e.g., to 32 or 64) may improve stability. |
| Connected | The selected bit becomes True when the connection to the device is established. |
| Fault | The selected bit becomes True when a communication error occurs. |
| Comment | Descriptive note for the device. |
Addressing Table
Wise SCADA uses the following prefixes for Mitsubishi PLC memory areas.
- Important Note (Hex vs Decimal)
In Mitsubishi addressing:
- Physical I/O such as X and Y use Hexadecimal numbering
(Example: X0, X1 … XF, X10). - Internal memory areas such as M and D use Decimal numbering.
| Address Type | Data Type | Description | Example |
| M | Bit | Internal Relay | M 0, M 100 |
| X | Bit | Physical Input (Hex) | X 0, X 1F |
| Y | Bit | Physical Output (Hex) | Y 0, Y 10 |
| B | Bit | Link Relay (Hex) | B 0, B 1A |
| D | Word (16-bit) | Data Register | D 0, D 100 |
| W | Word (16-bit) | Link Register (Hex) | W 0, W 1F |
| R | Word (16-bit) | File Register | R 0, R 50 |
| ZR | Word (16-bit) | Extended File Register | ZR 0, ZR 100 |
| L | Bit | Latch Relay | L 0, L 50 |
| F | Bit | Fault Relay (Annunciator) | F 0, F 10 |
| TN / CN | Word | Timer / Counter (Current Value) | TN 0, CN 5 |
| TS / CS | Bit | Timer / Counter (Contact Status) | TS 0, CS 5 |