With the continuous development of industrial fieldbus technology, CANopen and Profibus, as two major mainstream fieldbus protocols, are widely used in automation control systems. Although they each have distinct structures and communication methods, the correct configuration of termination resistors in actual wiring directly affects the signal integrity and communication reliability of the bus. So, what are the key differences in termination resistors between these two fieldbus systems?
1. What is a Termination Resistor?
A termination resistor is a component installed at both ends of the bus to match the impedance, prevent signal reflections, and ensure communication stability. Proper use of termination resistors can effectively reduce signal interference and data errors, thus guaranteeing the normal operation of the bus.
2. CANopen vs Profibus: Key Differences in Termination Resistors
| Name | CANopen Termination Resistors | Profibus Termination Resistors |
| Connector Type | M12 Connector | M12 Connector |
| Coding | A Code | B Code |
| Number of Pins | 5 Pin | 4 Pin |
| Typical Resistance | 120 ohm (Pin 4 & Pin 5) | 2*390 ohm + 220 ohm |
| Standard
|
|
IEC 61158 (PROFIBUS DP/PA) |
3. CANopen Termination Resistors
4. Profibus Termination Resistors
