Reference · built on requestConnectorPLC, SCADA & MES

MELSEC

Device memory, labels, and CPU state from MELSEC iQ-R, Q, and L series controllers over SLMP 3E and 4E frames on Ethernet.

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About

MELSEC is Mitsubishi Electric's programmable controller family. Its Ethernet-equipped modules and CPUs speak SLMP, a request-and-response protocol whose 3E and 4E frames match the QnA-compatible frames of the older MC protocol, so existing MC clients connect unchanged. The SLMP Reference Manual (SH-080956ENG) covers MELSEC iQ-R and iQ-L CPUs, MELSEC-Q and MELSEC-L built-in Ethernet CPUs and E71 modules, the MX Controller, and modules on CC-Link IE TSN. Messages travel over TCP/IP or UDP/IP in ASCII or binary code, and reach other stations through relay.

An operator on Fibric reads word and bit devices, labels, and CPU type and state, then proposes a device write or a remote operation for your approval. Writes go through interlocked logic you own, and every one leaves a receipt.

This is a reference listing. It documents what Fibric would read from MELSEC and what it could propose, based on the vendor's published interfaces. Fibric builds it under a managed deployment when you request it; selecting it here installs nothing.

Inputs

  • Bit and word devices read in batches with Device Read (command 0401): up to 960 word points per request
  • Scattered device addresses gathered in one Read Random (0403) or Read Block (0406) request
  • Values monitored as a set: register devices with Entry Monitor Device (0801), then poll them with Execute Monitor (0802)
  • Global and array labels on iQ-R and iQ-L CPUs through Label Read Random (041C) and Array Label Read (041A)
  • CPU model name from Read Type Name (0101), and buffer memory of intelligent function modules through Extend Unit Read (0601)

Proposed actions

  • Target capability: propose a device write with Device Write (1401), Write Random (1402), or Write Block (1406), shown with current values
  • Target capability: propose a label write on iQ-R or iQ-L CPUs through Label Write Random (141B) or Array Label Write (141A)
  • Target capability: propose a Remote Run (1001), Remote Stop (1002), or Remote Pause (1003) on a CPU module, for explicit approval
  • Target capability: propose Clear Error (1617) to initialize an error code and turn off the error LED once a fault is understood

Proposed actions are target capabilities. Every action runs propose-first and needs a validated deployment and the appropriate permissions.

What you can build

  • Keep fill weight on target

    Read the checkweigher's weight and reject registers each cycle, trend them per SKU, and propose a target-weight adjustment when the mean drifts.

    With Fill Weight

  • Prepare a changeover before the line stops

    Read the active recipe number and remaining count, then stage the next recipe's device values for approval so the switch happens once.

    With Changeover Plan

  • Find the compressor leak from pressure registers

    Monitor air pressure and compressor-run bits across idle periods, and flag the segment whose pressure decays while nothing consumes air.

    With Air Leak

  • Log downtime with its cause code

    Watch running and fault bits with Execute Monitor, stamp each stop with the CPU's error code, and open a downtime record for review.

    With Line Downtime

Requirements

  • An SLMP-compatible device: an iQ-R, iQ-L, Q, or L CPU with built-in Ethernet, an RJ71EN71, QJ71E71-100, or LJ71E71-100 module, or an MX Controller
  • An open TCP/IP or UDP/IP connection to that module, with frame type and data code (3E or 4E, ASCII or binary) agreed per connection
  • The remote password, if one is set, and the CPU's system protection released before any write
  • An interlock in the PLC program for anything written while the controller is running, as the manual's design precautions require
Authentication
A remote password set in the CPU or Ethernet module with the engineering tool and presented through SLMP command 1630, which releases the locked state: four characters on MELSEC-Q and L, 6 to 32 characters on iQ-R and iQ-L.

Limits

  • Requests extend the CPU's scan time; the manual advises smaller reads spread over several requests when control is affected
  • A device read or write is capped at 960 word points, or 3584 bit points in ASCII and 7168 in binary
  • The number of commands in flight per connection is bounded by the module's receive buffer; exceeding it can drop responses
  • Station numbers of 121 or higher need the station number extension frame, which only CC-Link IE TSN devices carry

Access and pricing

Reference listing. Fibric builds the connector under a managed deployment when you request it. Your quote covers the build, capabilities, usage, and support.

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Questions and answers

Is SLMP the same as the MC protocol?
The SLMP 3E and 4E frames use the same message format as the QnA-compatible 3E and 4E frames of the MC protocol, so devices built for MC protocol can talk to an SLMP-compatible device directly. Appendix 2 of the manual maps MC protocol commands to their SLMP equivalents.
Which MELSEC series does this listing cover?
Those the SLMP Reference Manual names: MELSEC iQ-R and iQ-L CPUs, MELSEC-Q and MELSEC-L built-in Ethernet CPUs, the QJ71E71-100, LJ71E71-100, and RJ71EN71 Ethernet modules, the MX Controller, and CC-Link IE TSN modules. Other series stay out of scope until their manuals are read.
Can the connector change a running controller?
The protocol allows it: Device Write, Write Random, Remote Run, Remote Stop, and Remote Pause are documented commands. Fibric only proposes them. The manual requires an interlock circuit in the program and warns that system protection returns an abnormal response until it is released on the CPU side.
Ask about MELSEC

Ask about the capabilities and requirements in this listing.

For project-specific requirements, contact Fibric.

This connector listing is developed, published, and supported by Fibric. It describes integration with MELSEC through published interfaces. Third-party names and logos identify the systems an integration connects to; they are the property of their respective owners, who are not affiliated with Fibric and do not sponsor or endorse this listing. Trademark policy