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.
The 6ES5928-3UA21 is a CPU 928A module designed for the SIMATIC S5-135U and S5-155U automation systems. This single-width central processing unit provides reliable logic execution and control capabilities for industrial automation environments. Engineered for robust performance, the CPU 928A ensures seamless integration into existing SIMATIC S5 infrastructures, serving as a key component for maintaining critical process automation.
System Compatibility: Designed for S5-135U and S5-155U programmable logic controllers.
Form Factor: Single-width module for compact cabinet installation.
Operational Reliability: Proven performance for industrial control tasks and process continuity.
Versatility: Supports both new installations and legacy system maintenance.
Automated manufacturing and production lines
Legacy PLC system maintenance and infrastructure upgrades
Process control and monitoring in heavy industry
Replacement and spare part for S5-135U and S5-155U systems
| Feature | Specification |
| Manufacturer | Siemens |
| Brand | SIMATIC S5 |
| Series | S5-135/155 |
| Module Type | CPU 928A |
| Product Phase | Obsolete |
| Predecessor | 6ES5928-3UA12 |
| Successor | 6ES5928-3UB21 |
| Dimensions (H x W x D) | 25.00 x 12.00 x 10.00 cm |
| Weight | 0.50 kg |
| Commodity Code | 85371091 |
Handling: Always ensure power is disconnected before installing or removing the CPU module to prevent electrical damage to the backplane or module circuitry.
Mounting: Insert the module into the designated slot of the S5-135U or S5-155U rack, ensuring it is seated securely. Use the locking mechanisms to fasten the unit to the chassis.
Environment: Operate within the specified environmental limits to prevent overheating or signal interference. Ensure the control cabinet is clean and dry.
Static Precautions: The module contains sensitive electronic components. Utilize anti-static wrist straps during handling to prevent damage from electrostatic discharge.
Global Express Shipping
Returns & Warranty







The 6ES5928-3UA21 is a CPU 928A module designed for the SIMATIC S5-135U and S5-155U automation systems. This single-width central processing unit provides reliable logic execution and control capabilities for industrial automation environments. Engineered for robust performance, the CPU 928A ensures seamless integration into existing SIMATIC S5 infrastructures, serving as a key component for maintaining critical process automation.
System Compatibility: Designed for S5-135U and S5-155U programmable logic controllers.
Form Factor: Single-width module for compact cabinet installation.
Operational Reliability: Proven performance for industrial control tasks and process continuity.
Versatility: Supports both new installations and legacy system maintenance.
Automated manufacturing and production lines
Legacy PLC system maintenance and infrastructure upgrades
Process control and monitoring in heavy industry
Replacement and spare part for S5-135U and S5-155U systems
| Feature | Specification |
| Manufacturer | Siemens |
| Brand | SIMATIC S5 |
| Series | S5-135/155 |
| Module Type | CPU 928A |
| Product Phase | Obsolete |
| Predecessor | 6ES5928-3UA12 |
| Successor | 6ES5928-3UB21 |
| Dimensions (H x W x D) | 25.00 x 12.00 x 10.00 cm |
| Weight | 0.50 kg |
| Commodity Code | 85371091 |
Handling: Always ensure power is disconnected before installing or removing the CPU module to prevent electrical damage to the backplane or module circuitry.
Mounting: Insert the module into the designated slot of the S5-135U or S5-155U rack, ensuring it is seated securely. Use the locking mechanisms to fasten the unit to the chassis.
Environment: Operate within the specified environmental limits to prevent overheating or signal interference. Ensure the control cabinet is clean and dry.
Static Precautions: The module contains sensitive electronic components. Utilize anti-static wrist straps during handling to prevent damage from electrostatic discharge.
Global Express Shipping
Returns & Warranty
Orders are processed and delivered Monday-Friday (excluding public holidays).
For full eligibility, restocking fees, and international return details, please view our official Refund & Return Policy .
| Color pattern |
Green
|
| Country of origin |
Germany
|
| Power source |
AC-powered
|