Implementing 3-Switch XOR Ladder Logic with Internal Bit
Implement a 3-SPST switch XOR light circuit in LogixPro or RSLogix 500 using an internal relay bit. Includes truth tables, boolean equations, and verified.
Designed for centralized control in mid-scale automation architectures, the Mitsubishi Electric Q02CPU functions as a high-performance programmable logic controller processor within the MELSEC Q Series family. This module coordinates sequence control and device data processing with an optimized instruction set, supporting highly stable operations across manufacturing lines. Featuring a compact modular footprint, it integrates directly into standard Q Series base units, enabling seamless expansion and communication with specialized I/O and network modules.
| Parameter | Value |
|---|---|
| Manufacturer | Mitsubishi Electric |
| Model Number | Q02CPU |
| Series | MELSEC Q Series |
| Program Capacity | 28 k steps |
| Program Memory | 112 KB |
| LD Instruction Execution Speed | 0.079 us |
| I/O Points | 4096 points (local/remote) |
| I/O Device Points | 8192 points |
| Internal Current Consumption (5V DC) | 0.60 A |
| Operating Temperature Range | 0 to 55 degC |
| Shipping Weight (Calculated) | 0.30 kg |
| Package Dimensions (Calculated) | 120 mm x 110 mm x 45 mm |
| Connector / Port | Interface Type | Function Assignment |
|---|---|---|
| Built-in Serial Port | RS-232 (Mini-DIN 6-Pin) | Programming, debugging, and direct HMI connection |
| Memory Card Interface | PCMCIA-compliant slot | External memory card installation (SRAM/Flash/ATA) |
The Q02CPU is a legacy standard model within the MELSEC Q series. For systems requiring faster processing speeds, integrated Ethernet connectivity, or expanded data logging, consider the Q03UDVCPU or Q04UDVCPU. When swapping to a Universal Q Series CPU, verify program parameters in GX Works2 as some specialized instruction behaviors and memory card formats vary between the classic Q02CPU and newer "Universal" (UD/UDV) modules.
The Q02CPU has a strict program limit of 28 k steps. Exceeding this limit will trigger compilation failures. When utilizing extensive file registers (ZR), ensure you allocate the memory blocks correctly in the PLC parameters before downloading. If the battery voltage drops, stored latch data and SRAM contents will be lost; always establish a periodic preventative maintenance schedule to replace the Q6BAT backup battery.
When connecting to the RS-232 port with a QC30R2 programming cable or third-party serial-to-USB converters, ensure the communications parameters in GX Works2/GX Developer match (baud rate, parity, stop bits). To prevent serial communication dropouts caused by high-frequency electromagnetic interference (EMI) from neighboring variable frequency drives (VFDs), ensure the base unit’s functional ground (FG) terminal is grounded directly to a low-impedance earth point.
Isolate and completely lock out the main power supply feeding the MELSEC Q base unit before mounting or removing the CPU module. Hot-swapping the CPU module is strictly prohibited and will result in irreversible hardware damage or unpredictable system behavior.
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Designed for centralized control in mid-scale automation architectures, the Mitsubishi Electric Q02CPU functions as a high-performance programmable logic controller processor within the MELSEC Q Series family. This module coordinates sequence control and device data processing with an optimized instruction set, supporting highly stable operations across manufacturing lines. Featuring a compact modular footprint, it integrates directly into standard Q Series base units, enabling seamless expansion and communication with specialized I/O and network modules.
| Parameter | Value |
|---|---|
| Manufacturer | Mitsubishi Electric |
| Model Number | Q02CPU |
| Series | MELSEC Q Series |
| Program Capacity | 28 k steps |
| Program Memory | 112 KB |
| LD Instruction Execution Speed | 0.079 us |
| I/O Points | 4096 points (local/remote) |
| I/O Device Points | 8192 points |
| Internal Current Consumption (5V DC) | 0.60 A |
| Operating Temperature Range | 0 to 55 degC |
| Shipping Weight (Calculated) | 0.30 kg |
| Package Dimensions (Calculated) | 120 mm x 110 mm x 45 mm |
| Connector / Port | Interface Type | Function Assignment |
|---|---|---|
| Built-in Serial Port | RS-232 (Mini-DIN 6-Pin) | Programming, debugging, and direct HMI connection |
| Memory Card Interface | PCMCIA-compliant slot | External memory card installation (SRAM/Flash/ATA) |
The Q02CPU is a legacy standard model within the MELSEC Q series. For systems requiring faster processing speeds, integrated Ethernet connectivity, or expanded data logging, consider the Q03UDVCPU or Q04UDVCPU. When swapping to a Universal Q Series CPU, verify program parameters in GX Works2 as some specialized instruction behaviors and memory card formats vary between the classic Q02CPU and newer "Universal" (UD/UDV) modules.
The Q02CPU has a strict program limit of 28 k steps. Exceeding this limit will trigger compilation failures. When utilizing extensive file registers (ZR), ensure you allocate the memory blocks correctly in the PLC parameters before downloading. If the battery voltage drops, stored latch data and SRAM contents will be lost; always establish a periodic preventative maintenance schedule to replace the Q6BAT backup battery.
When connecting to the RS-232 port with a QC30R2 programming cable or third-party serial-to-USB converters, ensure the communications parameters in GX Works2/GX Developer match (baud rate, parity, stop bits). To prevent serial communication dropouts caused by high-frequency electromagnetic interference (EMI) from neighboring variable frequency drives (VFDs), ensure the base unit’s functional ground (FG) terminal is grounded directly to a low-impedance earth point.
Isolate and completely lock out the main power supply feeding the MELSEC Q base unit before mounting or removing the CPU module. Hot-swapping the CPU module is strictly prohibited and will result in irreversible hardware damage or unpredictable system behavior.
Global Express Shipping
Returns & Warranty
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| Country of origin |
United States
|