NI 9852 Operating Instructions 12 ni.com
Determining the Necessary Termination Resistance for the Board
Unlike High-Speed CAN, Low-Speed/Fault-Tolerant CAN
requires termination at the Low-Speed/Fault-Tolerant CAN
transceiver instead of on the cable itself. Termination requires
tworesistors, RTH for CAN_H and RTL for CAN_L. This
configuration allows the Philips Fault-Tolerant CAN transceiver to
detect and recover from bus faults. It is important to determine the
overall termination of the existing network, or the termination of
the individual device, before connecting it to a
Low-Speed/Fault-Tolerant port. Philips recommends an overall
RTH and RTL termination of 100 to 500 Ω (each) for a properly
terminated low-speed network.
Termination on the low-speed/fault-tolerant ports of the NI9852 is
set through the NI 985x software to either 1kΩ or 5 kΩ.