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PLC setup guide

Configure the PLC before using any communication library. A power cycle is required after every parameter change.

For every protocol, choose and pass the canonical PLC profile explicitly when opening a standard connection — the libraries do not infer it from the PLC. The setup pages below list the profile to use for each model.

For MELSEC SLMP profile limits and end-code troubleshooting after the PLC-side settings are correct, use the SLMP profile reference and SLMP Troubleshooting & Codes.

Checking the connection after setup

You can confirm the settings before writing any code. For the three Ethernet protocols, PLC Scope is a Windows desktop tool that connects and shows live device values; keep the first check read-only, because it can also write devices and issue CPU RUN/STOP. For MC Protocol Serial, use the read-only bring-up scripts in examples/linux_cli of the MC Protocol Serial C++ library.

Supported models

Protocol Model Connection type Port
MELSEC SLMP iQ-R Built-in Ethernet 1025
MELSEC SLMP iQ-F Built-in Ethernet 1025
MELSEC SLMP iQ-L Built-in Ethernet 1025
MELSEC SLMP MX-R Built-in Ethernet 1025
MELSEC SLMP MX-F Built-in Ethernet 1025
MELSEC SLMP QnUDV Built-in Ethernet 1025
MELSEC SLMP QnU Built-in Ethernet 1025
MELSEC SLMP LCPU Built-in Ethernet 1025
MELSEC SLMP RJ71EN71 Communication unit 1025
MELSEC SLMP QJ71E71-100 Communication unit 1025
MELSEC SLMP LJ71E71-100 Communication unit 1025
KV Host Link KV-X500 Built-in Ethernet 8501
KV Host Link KV-8000 Built-in Ethernet 8501
KV Host Link KV-7000 Built-in Ethernet 8501
KV Host Link KV-5000 Built-in Ethernet 8501
KV Host Link KV-XLE02 Communication unit 8501
Computerlink TOYOPUC Ethernet 1025
MC Protocol Serial MELSEC serial modules Serial module (serial)

Protocol troubleshooting pages

These pages are shared by all language implementations for the same protocol.

Protocol Page
MELSEC SLMP Troubleshooting & Codes
KV Host Link Troubleshooting & Codes
Computerlink Troubleshooting & Codes
MC Protocol Serial Troubleshooting & Codes

Configuration tools

Tool Applies to
GX Works3 MELSEC iQ-R, iQ-F, iQ-L, MX-R, MX-F, RJ71EN71
GX Works2 MELSEC Q series (QnUDV, QnU, QJ71E71-100), L series (LCPU, LJ71E71-100)
KV Studio KEYENCE KV-X500, KV-8000, KV-7000, KV-5000, KV-XLE02

Simulator connection notes

GX Simulator 3

GX Simulator 3 uses IP 127.0.0.1 and port 5511 for SLMP over TCP.

The following parameter must be enabled:

  • Enable/Disable Online Change: Enable All (SLMP)

Simulator model support:

  • Model: iQ-R/iQ-L only

Verified with GX Works3 Version 1.125F.

KV STUDIO Simulator

KV STUDIO Simulator uses IP 127.0.0.1 and port 8501 for Host Link over TCP.

Simulator model support:

  • Model: KV-X500/KV-8000 only

Verified with KV STUDIO Ver.12.41.