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 to handle centralized discrete automation tasks, the Schneider Electric TM221C40R serves as a high-density, AC-powered main processing unit within the Modicon M221 logic controller range. This compact base controller features 40 integrated discrete I/O channels, consisting of 24 digital inputs and 16 relay outputs, complemented by 2 high-speed analog inputs. Optimized for small-to-medium industrial architectures, it provides robust control capabilities while minimizing cabinet space usage.
| Parameter | Value / Rating |
|---|---|
| Manufacturer | Schneider Electric |
| Product Range | Modicon M221 |
| Model / SKU | TM221C40R |
| Supply Voltage Range | 100 to 240 V AC |
| Discrete Input Count | 24 (including 4 fast inputs) |
| Discrete Output Type | Relay (Normally Open) |
| Discrete Output Count | 16 Relay Outputs |
| Analog Input Range | 2 inputs (0 to 10 V), 10-bit resolution |
| Relay Output Current | 2 A per output (maximum) |
| Programming Software | EcoStruxure Machine Expert - Basic |
| Operating Temperature | -10 to 55 degC (horizontal mounting) |
| Shipping Weight (Calculated) | 0.83 kg |
| Package Dimensions (Calculated) | 21.1 cm x 14.1 cm x 11.4 cm |
| Terminal / Port | Assignment / Function |
|---|---|
| L, N | AC Power Supply Mains Connection (100 to 240 V AC) |
| FG | Functional Ground Connection |
| I0 to I23 | Discrete Inputs (I0-I3 support High-Speed Counter functions) |
| Q0 to Q15 | Relay Outputs (arranged in isolated common groups) |
| AI0, AI1, COM | Analog Inputs (0 to 10 V) and shared Analog Common |
| Ethernet (RJ45) | Modbus TCP client/server protocol access |
| Serial (RJ45) | RS232/RS485 Serial Link communication configuration |
The TM221C40R directly replaces older Twido modular or compact controller configurations during system modernization. When translating applications from TwidoSuite or TwidoSoft to EcoStruxure Machine Expert - Basic, pay careful attention to memory allocation variables (%MW) and input mapping offsets, as slight syntax translations are required to prevent data collision.
Thermal dissipation limits require vertical spacing clearance of at least 50 mm above and below the controller housing. If the unit is installed vertically (90-degree rotation), the maximum ambient rating drops from 55 degC to 35 degC. Additionally, ensure transient voltage suppressors (snubbers) are wired across inductive AC loads connected to the relay outputs to prevent premature contact pitting.
The 0 to 10 V analog inputs (AI0, AI1) share a single ground (COM) that is tied to the internal logic ground. Using unshielded cable on these inputs in high-EMI environments can lead to control signal jitter. Always run analog signals in shielded twisted-pair (STP) cabling, grounding the shield only at the controller end.
CRITICAL WARNING
De-energize all primary and field sensor power distribution circuits before installing or removing terminals. Verify that all residual charge has fully bled down. Failure to isolate input power paths may result in severe electrical shock, system bus errors, or permanent circuit board damage.
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Returns & Warranty

Designed to handle centralized discrete automation tasks, the Schneider Electric TM221C40R serves as a high-density, AC-powered main processing unit within the Modicon M221 logic controller range. This compact base controller features 40 integrated discrete I/O channels, consisting of 24 digital inputs and 16 relay outputs, complemented by 2 high-speed analog inputs. Optimized for small-to-medium industrial architectures, it provides robust control capabilities while minimizing cabinet space usage.
| Parameter | Value / Rating |
|---|---|
| Manufacturer | Schneider Electric |
| Product Range | Modicon M221 |
| Model / SKU | TM221C40R |
| Supply Voltage Range | 100 to 240 V AC |
| Discrete Input Count | 24 (including 4 fast inputs) |
| Discrete Output Type | Relay (Normally Open) |
| Discrete Output Count | 16 Relay Outputs |
| Analog Input Range | 2 inputs (0 to 10 V), 10-bit resolution |
| Relay Output Current | 2 A per output (maximum) |
| Programming Software | EcoStruxure Machine Expert - Basic |
| Operating Temperature | -10 to 55 degC (horizontal mounting) |
| Shipping Weight (Calculated) | 0.83 kg |
| Package Dimensions (Calculated) | 21.1 cm x 14.1 cm x 11.4 cm |
| Terminal / Port | Assignment / Function |
|---|---|
| L, N | AC Power Supply Mains Connection (100 to 240 V AC) |
| FG | Functional Ground Connection |
| I0 to I23 | Discrete Inputs (I0-I3 support High-Speed Counter functions) |
| Q0 to Q15 | Relay Outputs (arranged in isolated common groups) |
| AI0, AI1, COM | Analog Inputs (0 to 10 V) and shared Analog Common |
| Ethernet (RJ45) | Modbus TCP client/server protocol access |
| Serial (RJ45) | RS232/RS485 Serial Link communication configuration |
The TM221C40R directly replaces older Twido modular or compact controller configurations during system modernization. When translating applications from TwidoSuite or TwidoSoft to EcoStruxure Machine Expert - Basic, pay careful attention to memory allocation variables (%MW) and input mapping offsets, as slight syntax translations are required to prevent data collision.
Thermal dissipation limits require vertical spacing clearance of at least 50 mm above and below the controller housing. If the unit is installed vertically (90-degree rotation), the maximum ambient rating drops from 55 degC to 35 degC. Additionally, ensure transient voltage suppressors (snubbers) are wired across inductive AC loads connected to the relay outputs to prevent premature contact pitting.
The 0 to 10 V analog inputs (AI0, AI1) share a single ground (COM) that is tied to the internal logic ground. Using unshielded cable on these inputs in high-EMI environments can lead to control signal jitter. Always run analog signals in shielded twisted-pair (STP) cabling, grounding the shield only at the controller end.
CRITICAL WARNING
De-energize all primary and field sensor power distribution circuits before installing or removing terminals. Verify that all residual charge has fully bled down. Failure to isolate input power paths may result in severe electrical shock, system bus errors, or permanent circuit board damage.
Global Express Shipping
Returns & Warranty
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For full eligibility, restocking fees, and international return details, please view our official Refund & Return Policy .
| Country of origin |
France
|