What do X, Y, M and D mean in Mitsubishi PLC programming?

X and Y are commonly used for discrete inputs and outputs, M for internal relays, and D for data registers. Exact ranges and addressing conventions depend on the controller family.

Does the simulator use Mitsubishi octal addressing?

No. The current parser deliberately maps X and Y with decimal bit indexing. The page states that deviation so learners do not mistake browser behavior for every physical MELSEC address rule.

Can this open a GX Works project file?

No. It runs text-based training examples and does not import, edit or download GX Works projects.

Mitsubishi PLC Programming — GX Works Examples

Mitsubishi PLC Programming: GX Works Devices and Examples

Learn how Mitsubishi X/Y inputs and outputs, M relays, D registers, T timers and C counters fit together—then run a small GX-style mnemonic program before opening a hardware project.

Independent learning tool. No hardware connection, vendor project import or controller download. Technical scope verified August 7, 2026.

Real Mitsubishi PLC programming footage

See this exact skill in the working simulator.

Watch the real browser product respond to the task on this page, then try the same practical workflow yourself. No slides, concept mockups, install, or credit card.

Try this in the browser

Mitsubishi PLC Simulator — Practise GX Works-Style Ladder Logic

Six Mitsubishi programming skills in context

See how device notation becomes a working machine sequence

Follow the same progression used on a practical training bench: identify the I/O and memory areas, build the motor permissive, add sequence devices and data, then validate the result in the correct engineering environment.

Generic compact PLC programming bench with ladder logic, wired inputs and output indicators for Mitsubishi-style browser practice — 01Begin with an observable bench where each input, internal state and output can be traced through the scan.

PLC device-memory training panel showing separated input, output, internal relay and data-register areas — 02Separate X/Y field I/O from M internal relays and D word data before reading the instruction sequence.

Motor-control training rig with start and stop buttons, PLC, contactor and motor for a Mitsubishi-style seal-in exercise — 03Use M0 as a visible seal-in state, then mirror that state to the physical Y output that drives the motor circuit.

Compact conveyor PLC lab with sensor, products and stack light for Mitsubishi-style timer and counter exercises — 04Add T and C devices only after the Boolean path is clear, so every timed or counted transition has a purpose.

PLC process lab with analog level transmitter, data display and test instruments for D-register practice — 05Use D registers for values and arithmetic, then verify that the data produces the intended process behavior.

Instructor and learner validating a generic PLC motor cell at an engineering workstation before commissioning — 06Transfer the proven logic into the correct GX Works project and validate the exact CPU, address rules and hardware safely.

Start with the Mitsubishi device model

MELSEC programs use compact device names throughout the logic. X and Y identify physical I/O, M is internal bit memory, D is word data, and T/C identify timer and counter instances. Reading those areas confidently is more valuable than memorising menu clicks.

GX Works2 and GX Works3 cover different generations and workflows. This page focuses on transferable program-reading and instruction skills; the linked software guide covers official downloads and platform selection.

Address translation sheet

Read the memory map before the rung

These are the address forms this learning runtime recognises. The final column states the simulator behavior, including intentional simplifications.

Device / area	Role	Example	Browser behavior
X	Discrete input	X0, X1, X8	The simulator deliberately uses decimal bit indexing: X8 maps to %I1.0.
Y	Discrete output	Y0, Y7, Y8	Maps to runtime output bytes using decimal indexing.
M	Internal relay	M0, M100	Maps into internal bit memory such as %M0.0.
D	Data register	D0, D100	Maps into word memory such as %MW0.
T / C	Timer / counter	OUT T0 K30, OUT C0 K10	Uses a fixed 100 ms timer base and literal counter preset.

Executable now

Supported instruction groups

Contacts and coils: LD, LDI, AND, ANI, OR, ORI and OUT
Block logic: ANB and ORB
Latching: SET and RST
Data operations: MOV, ADD, SUB, MUL and DIV as standalone operations

Do not assume

Not in the current subset

MPS, MRD and MPP branch-stack instructions
TOF and CTD in the Mitsubishi mnemonic parser
Exact octal/hex addressing rules of every MELSEC family
GX project files, hardware configuration and controller download

Worked example

A GX-style motor permissive

The first rung seals the start request into M0 until X1 breaks the path; the second mirrors that internal relay to Y0. It runs in the Mitsubishi parser.

Run your own program

Mitsubishi mnemonicParser-valid example

; M0 seals in the motor request
LD   X0
OR   M0
ANI  X1
OUT  M0
LD   M0
OUT  Y0

Learning sequence

From device names to a maintainable MELSEC program

01
Separate physical and internal devices
Mark X/Y as field I/O and M/D as program memory before following any branches.
02
Trace the result of each instruction
Follow the result-of-logic operation through LD, AND/ANI, OR/ORI and OUT.
03
Add timers, counters and data
Practise T/C done states and basic D-register moves without hiding the sequence in a large project.
04
Recreate it in GX Works
Select the real CPU, check its address rules, configure hardware and commission through Mitsubishi’s tools.

Engineering boundary

GX-style practice is not GX Works emulation

The browser parser models a useful Mitsubishi mnemonic subset. It intentionally normalises some addressing and timing behavior so exercises remain deterministic across the training runtime.

X/Y device mapping here uses decimal bit indexing, which may differ from the target MELSEC family.
The fixed timer base is a learning simplification, not a controller timing specification.
GX Works remains required for real project files, diagnostics and hardware transfer.

Technical evidence

Sources and verification

Page claims and the simulator support matrix were reviewed against the production parser and these primary technical sources on August 7, 2026.

Continue through the cluster

Related programming and simulator guides

Mitsubishi PLC simulator

Review exactly what the browser executes and what stays in GX Works.

GX Works software guide

Find the correct official engineering-tool path.

Instruction List simulator

Compare Mitsubishi mnemonics with IEC IL.

Questions

Mitsubishi PLC Programming FAQ

That depends on the MELSEC family you will encounter. GX Works2 remains relevant to older projects, while GX Works3 is the current environment for newer iQ-F and iQ-R workflows. Match the software to the actual controller.

Turn Mitsubishi device notation into working logic

Practise the supported GX-style subset in the browser, then transfer the reasoning into the correct MELSEC project.

Start free Compare all dialects