Skip to content

MELSEC iQ-R — PLC-side settings

MELSEC iQ-R — built-in Ethernet port (CPU module).

What you need

  • Configuration tool: GX Works3
  • Network: Align IP address, subnet mask, and default gateway with your network environment.
  • After configuration: Power cycle the PLC to apply the new parameters.

Example values used in this guide

Parameter Example value Notes
IP address 192.168.250.100 Adapt to your network
TCP port 1025 SLMP TCP
UDP port 1035 SLMP UDP

PLC-side settings

Screen: Unit parameters

Parameter Setting
IP Address 192.168.250.100 (example)
Subnet Mask Match your network
Default Gateway Match your network
Write Permission During RUN Permit all (SLMP)
Communication Data Code Binary
Open Method Setting Do not open via program

Screen: Remote device connection settings

Parameter TCP UDP
Communication Method SLMP SLMP
Protocol TCP UDP
Port Number 1025 1035
Keep-Alive Enabled UDP

Connecting with this library

Parameter Value
Canonical profile melsec:iq-r
Port (TCP) 1025
Port (UDP) 1035

Code example:

import asyncio

from slmp import SlmpConnectionOptions, SlmpTarget, open_and_connect, read_typed


async def main() -> None:
    options = SlmpConnectionOptions(
        host="192.168.250.100",
        port=1025,
        transport="tcp",
        plc_profile="melsec:iq-r",
        default_target=SlmpTarget(network=0, station=0xFF, module_io=0x03FF, multidrop=0),
    )
    async with await open_and_connect(options) as client:
        value = await read_typed(client, "D100", "U")
        print(f"D100={value}")


asyncio.run(main())

using PlcComm.Slmp;

var options = new SlmpConnectionOptions(
    "192.168.250.100", SlmpPlcProfile.IqR, 1025,
    SlmpTransportMode.Tcp, SlmpTargetAddress.OwnStation);
await using var client = await SlmpClientFactory.OpenAndConnectAsync(options);
var value = await client.ReadTypedAsync("D100", "U");
Console.WriteLine($"D100={value}");

The PLC-side settings on this page apply to every language. For Rust, C++ (Arduino/PlatformIO), and Node-RED, start from each library's Getting started.

Multi-CPU CPU-buffer target

U3E0\HG... through U3E3\HG... are qualified iQ-R CPU-buffer device routes. The qualified device and the SLMP request destination are independent fields. Cross-CPU reads can therefore be intentional and must not be rejected merely because those fields name different CPUs.

When a write must be reflected in CPU No. n, explicitly select both U3En\HG... and request-target module I/O 0x03En. A write sent to another CPU or Own Station can return a normal end code without changing the intended CPU buffer. The libraries do not infer or change the request target from the qualified device, retry another CPU, perform an automatic readback, or resend when a value does not appear. Target selection remains an application decision.

Screenshots

Unit parameters screen for the built-in Ethernet port Unit parameters screen for the built-in Ethernet port.

Remote device connection settings for SLMP communication Remote device connection settings for SLMP communication.