Allen-Bradley 1769-L20 CompactLogix Processor Module
Manufacturer: Allen Bradley
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Part Number: 1769-L20
Condition：New with Original Package
Product Type: CPU Processors
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Country of Origin: USA
Payment:T/T, Western Union
Shipping port: Xiamen
Warranty: 12 months
Allen-Bradley 1769-L20 CompactLogix Processor Module
The Allen-Bradley 1769-L20, also cataloged as the 1769-L20 Processor Module, operates as a dedicated hardware component for specific technical task execution within CompactLogix 1769 platforms. The unit coordinates local backplane operations and manages asynchronous serial communication lines directly from the embedded processing core.
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 1769-L20 |
| Brand | Allen-Bradley |
| Origin | United States |
| Weight | 0.75 lbs (0.34 kg) |
| Dimensions | Standard 1769 module width |
| Operating Temp | 0 to +60 deg C |
| Power Consumption | 800 mA @ 5 VDC backplane current draw |
| User Memory | 0.75 MB |
| I/O Capacity | Up to 8 local 1769 I/O modules |
| Communication Ports | 1 x RS-232 serial port |
| Network Expansion Options | DeviceNet, EtherNet/IP, ControlNet via network modules |
| Motion Control Axis Capacity | Up to 2 axes via SERCOS interface module |
| Programming Protocols | DF1, ASCII, Modbus RTU |
| Storage Temp | -40 to +85 deg C |
| Relative Humidity | 5% to 95% RH, non-condensing |
| Replacement Terminal Block | 1769-RTBN18 |
| Wire Size (Solid) | 22 to 14 AWG copper wire rated for 90 deg C |
| Wire Size (Stranded) | 22 to 16 AWG copper wire rated for 90 deg C |
| System Software | RSLogix 5000 / Studio 5000 Logix Designer |
| Certifications | CE, UL, CSA |
Deterministic Network Architecture
The local logic engine governs up to 8 local modules, maintaining a stable backplane bus communication velocity across the internal hardware bus. Industrial networks require precise data prioritization; consequently, this controller implements fixed scan allocations to stabilize I/O density scaling. The embedded firmware flash compatibility guarantees deterministic scheduling for linked peripheral networks including EtherNet/IP or DeviceNet. When integrating up to 2 axes of synchronized motion via a SERCOS interface module, the local 0.75 MB memory registers compute step executions linearly without interrupting standard discrete program cycles.
Frequently Asked Questions
Q: Does the 1769-L20 processor module support the installation of more than 8 local modules if an expansion power supply is used?
A: No. The internal processor firmware enforces a strict hardware limit of 8 local I/O modules max. To expand total I/O point count past this limit, engineers must establish a remote network drop using a communication interface adapter.
Q: Can an engineer swap or replace the 1769-L20 module while the power distribution rail remains live?
A: No. The 1769 chassis platform lacks structural provisions for active circuit separation. Operators must isolate all power lines from the backplane before removing or inserting modules to avert data corruption and component failure.
Field Installation Guidelines
- Chassis Attachment Verification: Mount the processor module firmly onto standard symmetrical DIN rail tracks. Lock the side-locking mechanism securely to establish adequate structural rigidity and grounding continuity.
- Bus Termination Implementation: Install a 1769 right-end cap onto the final module of the local bank. The controller cannot clear internal bus faults if this terminating resistor network remains disconnected.
- Terminal Wiring Restrictions: Terminate all RS-232 serial links using shielded cable options. Strip solid or stranded copper wire (rated for 90 deg C minimum) to the specified length before securing the terminals inside the 1769-RTBN18 block.