Mitsubishi PLC
Fundamentals of Applications
1. Common Series of Mitsubishi PLC
1. FX Series
Features: Compact, economical, suitable for simple control (e.g., FX3U, FX5U).
Applications: Small equipment, assembly line control, simple logic control.
2. Q Series
Features: Modular design, strong expandability, suitable for complex systems.
Applications: Large production lines, multi-axis motion control, networked systems.
3. L Series
Features: Mid to high-end performance, supports high-speed processing and multi-protocol communication.
Applications: Smart manufacturing, process control, energy management.
2. Basic Hardware of PLC
1. Basic Components
CPU Module: Executes programs, processes data.
Input Module (X): Receives signals from sensors and buttons (e.g., X0, X1).
Output Module (Y): Controls actuators (e.g., Y0 to Y7 to drive solenoids, motors).
Power Module: Supplies power to the PLC.
Expansion Module: Increases I/O points or functions (e.g., analog, communication modules).
2. Wiring Example
Input side: Sensors (NPN/PNP) connect to COM terminal and X points.
Output side: Relay/ transistor output connects to load (e.g., Y points → contactor coil).
3. Programming Software and Development Environment
1. Software Tools
GXWorks2: Suitable for FX series, Q series (traditional programming).
GXWorks3: Supports the latest FX5U, L series (structured programming).
2. Programming Languages
Ladder Diagram (LD): The most commonly used, similar to circuit diagrams.
Instruction List (IL): Code-based programming (e.g., LDX0, OUTY0).
Structured Text (ST): High-level language, suitable for complex algorithms.
4. Basic Instructions and Logic Control
1. Common Instructions
LD (Normally Open Contact): LDX0 (turns on when X0 is activated).
LDI (Normally Closed Contact): LDIX1 (turns on when X1 is deactivated).
OUT (Output): OUTY0 (drives Y0 output).
AND/ANI (AND Logic): Series contacts.
OR/ORI (OR Logic): Parallel contacts.
SET/RST (Set/Reset): Maintains output state.
5. Timers and Counters
1. Timer (T):
Types:
Standard Timer (e.g., T0K50, delays 5 seconds).
Cumulative Timer (retains timing value after power loss).
Applications: Motor delay start, alarm timing control.
2. Counter (C):
Types:
Incremental Counter (e.g., C0K10, counts 10 triggers).
Decremental Counter.
Applications: Production counting, workpiece position detection.
6. Communication and Expansion
1. Communication Protocols
RS485/232: Communicates with touch screens, inverters.
CCLink: Mitsubishi’s proprietary industrial network.
Ethernet: Remote monitoring, data acquisition.
2. Expansion Modules
Analog Module (FX3U4AD): Collects temperature, pressure signals.
Positioning Module (FX5U32MT): Controls servo motor positioning.
7. Debugging and Maintenance
1. Debugging Steps
Download the program to the PLC.
Use software to monitor real-time I/O status.
Force input/output testing (ensure logic correctness).
2. Common Issues
PLC not running: Check RUN/STOP switch, program errors.
Output not functioning: Check wiring, load power, output point damage.
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