# Quick Answer: Can You End A Resistor?

## WHY CAN bus has 120 ohm resistor?

For avoiding reflection we use Transmission Line theory.

For the High speed CAN bus the maximum length is 40m, with 1 Mbps speed and maximum of 30 nodes.

So here by using 120 ohms resistor as terminating resistor we can avoid all the reflections easily without fail..

## CAN bus voltage too high?

Normally the voltage should be between 2.0 V and 4.0 V. If it is lower than 2.0 V or higher than 4.0 V, it is possible that one or more nodes have faulty transceivers. … To find the node with a faulty transceiver please test the CAN transceiver resistance (see section 1.4).

## CAN bus with 60 ohm termination?

a single 60 ohm termination for lab testing when bus is only a few feet (probably not allowed, but it works). If you don’t have two 120-ohm resistors, you can accomplish the termination (on a small network) with a single 60 ohm resistor(120 in parallel with 120 is 60) or anything close 55-65 is fine.

## CAN bus terminating resistor value?

The most common CAN-Bus issue is too much or too little termination resistance. In a low speed CAN each device should have a 120 Ohm resistor. In a high speed CAN-Bus (>100Kbit, used in automotive) only each end of the main loop should have a 120 Ohm resistor.

## Why termination resistor is used in can?

Terminal resistors are needed in CAN bus systems because CAN communication flows are two-way. The termination at each end absorbs the CAN signal energy, ensuring that this is not reflected from the cable ends. Such reflections would cause interference and potentially damaged signals.

## How do you know if a resistor is terminated?

To check your network’s termination, disconnect the CAN interface’s D-sub 9 pin from the network and measure resistance through the cable by placing a digital multimeter / ohmmeter between pin 2 and 7. Make sure any CAN nodes e.g. a motor controller, are still attached but powered down.

## CAN bus multiple termination?

To avoid reflections on the CAN bus, two terminations of 120 Ω must be foreseen at each end of the CAN bus. Depending on the application, one termination of 60 Ω can also be sufficient. In this application only one resistor is used (for each CAN bus) of 60 Ω in the Network Connection Board (see also Figure 3).

## Can tolerance resistor be terminated?

To preserve network functionality in a scenario where a data line fails to open, termination resistors are required at each node. These extra fault-tolerance features limit the maximum speed of a low-speed/fault-tolerant CAN network to 125 kbit/s.

## CAN Bus active Terminator?

The Active Terminator is where the CANBUS starts. It contains six wires and feeds the CANBUS system from battery power. It makes sure CAN Power is always 12V.