1. Product Overview
The BUELEC CANDB9120ohm is a specialized DB9 connector designed to function as a 120 Ohm terminal resistor for CAN (Controller Area Network) bus systems. This device is crucial for maintaining signal integrity in CAN communication networks by preventing signal reflections, which can lead to data corruption and communication errors.
In CAN bus communication, specific pins are designated for signal transmission: Pin 2 for CAN_L (low signal) and Pin 7 for CAN_H (high signal). The integrated 120 Ohm resistor between these two pins serves to terminate the bus, absorbing signals at the end of the line and eliminating echo interference. Without proper termination, reflected waves can overlap with correct signals, causing waveform distortion and incomplete communication protocols.
Image 1.1: A pack of five BUELEC CAN DB9 120 Ohm Terminal Resistors. These connectors are essential for proper CAN bus termination.
2. Key Features
- Integrated 120 Ohm Resistor: Features a high-precision 120 Ohm resistor built-in between Pin 2 (CAN_L) and Pin 7 (CAN_H) for effective bus termination.
- Direct Connection: Designed as a male-to-female interface, allowing direct connection to the DB9 port of any CAN bus analyzer without requiring cable modifications.
- Enhanced Durability: Utilizes custom bonding for improved resistance and high-temperature tolerance, ensuring reliable performance in various environments.
- Optimized Power Calculation: Power parameters are calculated in accordance with TI CAN chip communication standards, making it suitable for applications with stringent communication error rate requirements.
- Broad Compatibility: Compatible with a wide range of CAN analyzers, including PCAN, GC-CAN-USB, Peak-CAN, ZLG-USBCAN, VECTOR-CAN, and Vehicle Spy.
3. Setup and Installation
The BUELEC CANDB9120ohm terminal resistor is designed for straightforward installation. It should be connected directly to the DB9 port of your CAN device or analyzer at the end of the CAN bus line.
- Identify the DB9 port on your CAN bus device or analyzer where termination is required.
- Ensure the device is powered off before making any connections.
- Align the male end of the CANDB9120ohm connector with the female DB9 port on your device.
- Gently push the connector into place until it is fully seated.
- Secure the connection using the retaining screws on the DB9 connector, if available.
The internal 120 Ohm resistor is pre-wired between Pin 2 (CAN_L) and Pin 7 (CAN_H) of the DB9 interface, ensuring correct termination upon connection.
Image 3.1: Diagram illustrating the internal 120 Ohm resistor connection between CAN_H (Pin 7) and CAN_L (Pin 2) within the DB9 connector, crucial for proper CAN bus termination.
4. Operation
Once installed, the BUELEC CANDB9120ohm operates passively as a critical component of your CAN bus network. Its primary function is to provide the necessary 120 Ohm termination at the end of the bus line. This termination prevents signal reflections that can occur when electrical signals reach the end of a transmission line, ensuring that the CAN bus signals are clear and free from interference.
The resistor helps maintain the integrity of the communication protocol, allowing for accurate and reliable data transmission across the CAN network. No user interaction is required for its operation after proper installation.
5. Specifications
| Specification | Detail |
|---|---|
| Model Number | CANDB9120ohm |
| Brand | BUELEC |
| Connector Type | DB9 (Male to Female) |
| Resistance Value | 120 Ohm |
| Resistance Accuracy | One thousandth (e.g., 119.6 Ohm to 120.4 Ohm) |
| Power Rating | 0.25W |
| Compatible Devices | CAN tools with DB9 interface |
| Usage Environment | Indoor |
| Package Dimensions | 8.8 x 8.1 x 4.9 cm |
| Package Weight | 60 grams |
Image 5.1: A multimeter displaying a 120 Ohm reading, demonstrating the integrated resistance of the BUELEC CAN DB9 terminal resistor.
Image 5.2: Detailed view of the BUELEC CAN DB9 120 Ohm terminal resistor, highlighting its 120 Ohm resistance, one-thousandth accuracy, and 0.25W power rating. Products undergo strict inspection to ensure stable pin connections.
6. Troubleshooting
If you experience issues with your CAN bus communication after installing the BUELEC CANDB9120ohm, consider the following troubleshooting steps:
- Connection Check: Ensure the connector is fully seated and securely fastened to the DB9 port. Loose connections can lead to intermittent communication.
- Pin Assignment: Verify that the CAN bus device you are connecting to uses the standard DB9 pinout for CAN (Pin 2 for CAN_L, Pin 7 for CAN_H).
- Resistor Verification: If possible, use a multimeter to confirm the 120 Ohm resistance across Pin 2 and Pin 7 of the connector.
- Bus Topology: Confirm that the terminal resistor is placed at the physical end of the CAN bus line. Incorrect placement can still cause reflections.
- Other Terminators: Ensure that there are only two 120 Ohm terminators on the entire CAN bus (one at each physical end). Additional terminators can cause signal degradation.
7. Maintenance
The BUELEC CANDB9120ohm terminal resistor requires minimal maintenance due to its robust design. To ensure optimal performance and longevity:
- Keep Clean: Periodically inspect the connector for dust or debris. Use a soft, dry cloth to gently clean the exterior. Avoid using liquid cleaners directly on the pins.
- Storage: When not in use, store the connector in a clean, dry environment, away from extreme temperatures and direct sunlight.
- Handle with Care: Avoid excessive force when connecting or disconnecting to prevent damage to the pins or housing.
8. Warranty and Support
For information regarding warranty coverage, technical support, or any product-related inquiries, please refer to the documentation provided with your purchase or contact BUELEC customer service directly. Contact details can typically be found on the manufacturer's official website or product packaging.