Allen-Bradley 1769-ECL CompactLogix Left End Cap
Configured for communication bus termination in CompactLogix and MicroLogix 1500 systems, the Allen-Bradley 1769-ECL (1769-ECL End Cap) provides direct physical/electrical execution. It terminates the left end of the 1769 Compact I/O parallel backplane bus, preventing signal reflections and maintaining impedance stability across connected modules. The component mounts directly adjacent to the left-most module without requiring additional external power supplies or network configuration.
Suffix Breakdown & Model Matrix
| Model Suffix | Orientation / Application | Series Compatibility |
|---|---|---|
| 1769-ECL | Left-End Cap Terminator | Series A and B |
| 1769-ECR | Right-End Cap Terminator | Series A and B |
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 1769-ECL |
| Brand | Allen-Bradley |
| Origin | USA |
| Weight | 0.11 lbs (0.05 kg) |
| Dimensions | Standard 1769 Single-Slot Profile |
| Operating Temp | 0 to 60 deg C (32 to 140 deg F) |
| Power Consumption | Passive Termination Circuitry |
| Enclosure Type | Open Style |
| System Compatibility | Allen-Bradley CompactLogix / MicroLogix 1500 |
| Termination Position | Left-Most Slot Interface |
Backplane Bus & Deterministic Communications
The 1769-ECL maintains backplane bus communication velocity across CompactLogix I/O structures by providing differential line termination. By suppressing high-frequency noise injection and packet reflection on the parallel bus lines, it preserves deterministic scan timing and firmware flash compatibility across all backplane-connected modules.
Frequently Asked Questions
Q: What error occurs if the 1769-ECL left end cap is missing from a CompactLogix bank?
A: The controller will register a backplane bus fault due to an unterminated signal loop, blocking I/O image table updates and halting execution.
Q: Can the 1769-ECL be used on the right side of a 1769 Compact I/O bank?
A: No, the 1769-ECL is physically keyed exclusively for left-side termination. Right-side termination requires the 1769-ECR model.
Field Installation Guidelines
- Power Isolation: Turn off system backplane power prior to attaching or removing the end cap.
- Alignment & Insertion: Align the guide rails on the right face of the 1769-ECL with the corresponding slots on the left-most 1769 module.
- Bus Lever Engagement: Slide the end cap flush against the adjacent module and push the bus lever into the locked position to establish backplane termination.
- Mounting: Ensure the end cap is securely snapped onto the 35 mm DIN rail or fastened via panel-mounting screws.
- ESD Precautions: Handle the module using standard electrostatic discharge protection practices to safeguard internal passive termination networks.
Allen-Bradley 1769-ECL CompactLogix Left End Cap
Allen-Bradley 1769-ECL CompactLogix Left End Cap
Configured for communication bus termination in CompactLogix and MicroLogix 1500 systems, the Allen-Bradley 1769-ECL (1769-ECL End Cap) provides direct physical/electrical execution. It terminates the left end of the 1769 Compact I/O parallel backplane bus, preventing signal reflections and maintaining impedance stability across connected modules. The component mounts directly adjacent to the left-most module without requiring additional external power supplies or network configuration.
Suffix Breakdown & Model Matrix
| Model Suffix | Orientation / Application | Series Compatibility |
|---|---|---|
| 1769-ECL | Left-End Cap Terminator | Series A and B |
| 1769-ECR | Right-End Cap Terminator | Series A and B |
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 1769-ECL |
| Brand | Allen-Bradley |
| Origin | USA |
| Weight | 0.11 lbs (0.05 kg) |
| Dimensions | Standard 1769 Single-Slot Profile |
| Operating Temp | 0 to 60 deg C (32 to 140 deg F) |
| Power Consumption | Passive Termination Circuitry |
| Enclosure Type | Open Style |
| System Compatibility | Allen-Bradley CompactLogix / MicroLogix 1500 |
| Termination Position | Left-Most Slot Interface |
Backplane Bus & Deterministic Communications
The 1769-ECL maintains backplane bus communication velocity across CompactLogix I/O structures by providing differential line termination. By suppressing high-frequency noise injection and packet reflection on the parallel bus lines, it preserves deterministic scan timing and firmware flash compatibility across all backplane-connected modules.
Frequently Asked Questions
Q: What error occurs if the 1769-ECL left end cap is missing from a CompactLogix bank?
A: The controller will register a backplane bus fault due to an unterminated signal loop, blocking I/O image table updates and halting execution.
Q: Can the 1769-ECL be used on the right side of a 1769 Compact I/O bank?
A: No, the 1769-ECL is physically keyed exclusively for left-side termination. Right-side termination requires the 1769-ECR model.
Field Installation Guidelines
- Power Isolation: Turn off system backplane power prior to attaching or removing the end cap.
- Alignment & Insertion: Align the guide rails on the right face of the 1769-ECL with the corresponding slots on the left-most 1769 module.
- Bus Lever Engagement: Slide the end cap flush against the adjacent module and push the bus lever into the locked position to establish backplane termination.
- Mounting: Ensure the end cap is securely snapped onto the 35 mm DIN rail or fastened via panel-mounting screws.
- ESD Precautions: Handle the module using standard electrostatic discharge protection practices to safeguard internal passive termination networks.
