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Protocols

Mitsubishi MC protocol (SLMP)

Connect MELSEC iQ-R, iQ-F, Q and L controllers with the MC protocol over Ethernet and use their devices in OPC UA, SCADA and reports.

  • mc3e_binary
  • mc3e_ascii
  • mc4e_binary
  • mc4e_ascii

The MC protocol (MELSEC communication protocol, in newer documents SLMP) gives direct access to the device memory of Mitsubishi controllers. PLCGateway supports the QnA-compatible 3E frame and the 4E frame, each in binary and ASCII coding, over TCP or UDP.

Word devices are merged into blocks of up to 960 words and bit devices are read as 16-bit words, so even large device lists need only a few requests. For iQ-R the extended device codes are used automatically when the series is set.

Driver id
mc3e_binary mc3e_ascii mc4e_binary mc4e_ascii
Connection
TCP / UDP · binary or ASCII
Address browsing
addresses are typed or imported
Writing
yes

What PLCGateway reads and writes

  • Data registers D, link registers W, file registers R and ZR
  • Bit devices M, L, F, V, B, X, Y, SM and special registers SD
  • Hexadecimally numbered devices such as X1A or W1F0
  • Timers and counters: current value, contact and coil
  • Bits of word devices (D100.3) and 32-bit values across two registers
  • Writing of words and bits

Address examples

AddressMeaning
D100Data register 100
D200 (FLOAT32)REAL value in D200–D201
D100.3Bit 3 of D100
M100 · SM400Internal relay / special relay
X1A · Y20 · W1F0Hexadecimally numbered devices
ZR1000 · TN5 · CN3File register / timer value / counter value

Controllers and devices

Equipment that is typically connected with this driver.

Connect in a few steps

  1. In GX Works open an Ethernet port for the MC protocol (SLMP) as TCP or UDP and allow writing in RUN if values are to be written.

  2. Add a device with frame (3E or 4E), coding (binary or ASCII), IP address and port, and choose the series (Q/L/FX5 or iQ-R).

  3. Enter the device addresses as tags or import them from CSV and test the connection.

  4. Share the values over OPC UA or use them in screens, reports and OEE.

Questions and answers

Is SLMP the same as the MC protocol?

SLMP is the name Mitsubishi uses for the MC protocol on newer controllers; the 3E and 4E frames are compatible. PLCGateway works with both names.

Does it work with the FX5U built-in Ethernet port?

Yes. Configure an SLMP connection on the built-in port in GX Works3 and select the series Q/L/FX5 in PLCGateway.

Are older FX3 controllers supported?

FX3 controllers with an Ethernet adapter use a different (1E) frame. Connect them through a gateway that offers Modbus TCP or OPC UA, or ask us about your installation.

Connect your machines

Tell us which controllers you run; we show you PLCGateway with your own addresses.

Product and model names are trademarks of their owners. They are named only to show which equipment the drivers communicate with; PLCGateway is not affiliated with these companies.