MITSUBISHI MELSEC
Communicates with MITSUBISHI ELECTRIC PLC series using their standard communication protocol (MC protocol).
Supported series: Q / L / iQ-R / iQ-F / FX
Registration form entries
| Field | What to enter | Example |
|---|---|---|
| IP address | PLC's IP | 192.168.0.60 |
| Port | MC protocol port | 5000 (typical for Q/L) / 1500 (typical for iQ-R) |
| Controller Type (controller-type) | PLC series type | Q_L (Q/L series, default) / QnA / IQ_R / A — iQ-F and FX families use Q_L |
| Read mode (read-mode) | single (individual read per tag, default) / grouped (grouped batch read — minimizes round trips) | single |
| Batch merge gap (batch-gap-words) | Address gap within which word blocks may be merged in grouped mode | 16 (default) |
| String charset (string-charset) | String tag encoding (Korean supported) | MS949 (default) |
| iQ-R extended devices (enable-iqr-extended) | Whether to use iQ-R extended devices such as LCN/LZ/LF/LSTN/LCC/LSC | true to enable (disabled by default) |
MITSUBISHI PLCs also do not use a username or password. The PLC side must have "MC protocol / TCP / port" enabled (configured in GX Works).
Default port / Controller Type by series
| Series | Common port | controller-type |
|---|---|---|
| Q / L | 5000 or 1029 | Q_L |
| QnA | (PLC configured value) | QnA |
| iQ-R | 1500 | IQ_R |
| iQ-F | 1500 | Q_L (3E frame compatible) |
| A | (PLC configured value) | A |
| FX | (PLC configured value) | Q_L (3E frame compatible) |
On MITSUBISHI equipment, the port is assigned freely to the Ethernet module in GX Works / GX Developer. The table above lists only commonly used defaults; check the value actually in use with the PLC engineer or under [Ethernet Parameters] in GX Works.
PLC address notation for tags
MITSUBISHI PLC memory areas and their short notation:
| Notation | Area | Notes |
|---|---|---|
D100 | Data Register 100 | Most common, 16-bit |
M100 | Internal Relay 100 | 1 bit |
X100 | Input X100 | Input bit |
Y100 | Output Y100 | Output bit |
B0 | Link Relay 0 | 1 bit |
W100 | Link Register 100 | 16-bit |
R100 | File Register 100 | 16-bit |
T100 | Timer | |
C100 | Counter |
Reading 32-bit / 64-bit values as a pair
A single D100 location is 16-bit, so storing a 32-bit integer or float uses two locations (D100 + D101) together. In the gateway, specify the width in the [Format modifier] field.
| Value in the PLC | Data type | Format modifier | PLC address example |
|---|---|---|---|
| Bit (M, X, Y) | Boolean | (leave empty) | M100, X100, Y100 |
| 16-bit integer | Integer | (leave empty) | D100 |
| 16-bit unsigned | Integer | UI | D100 |
| 32-bit integer | Integer | DW | D100 (uses D100–D101) |
| 32-bit unsigned | Integer | UDW | D100 |
| 32-bit float (most common float type) | Float | REAL | D200 |
| 64-bit float | Double | LREAL | D300 |
| String of N words (= 2N characters) | String | STR[N] | D500 (uses D500–D515) |
Common problems and fixes
| Symptom / message | Possible cause | Fix |
|---|---|---|
| "Connection refused" | MC protocol disabled on the PLC side | GX Works → PLC parameters → built-in Ethernet → enable MC protocol / TCP / port |
| "Wrong device code" | Device type not supported | Check that controller-type matches the PLC series (codes differ between Q and iQ-R) |
| 32-bit values look wrong | Width not set | Specify DW (integer) / REAL (float) in the format modifier |
All tags show 0 | Mismatch in the PLC-side Ethernet/station settings | The gateway communicates using the default frame (direct local station) — check the Ethernet parameters (port/protocol) in GX Works |
Korean strings appear garbled as ? | String charset mismatch | Match the string-charset option to the PLC/HMI code page (default MS949) |
Frequently used examples
Registering run status, counter, and pressure together
| Tag name | PLC address | Data type | Format modifier |
|---|---|---|---|
| Pump running | M100 | Boolean | (leave empty) |
| Production counter | D100 | Integer | (leave empty) |
| Pressure (Pa) | D200 | Float | REAL |
| Cumulative run time | D102 | Integer | DW |
More detailed examples / automated registration
See the MELSEC examples in Advanced — REST API.