InteliPro, SW version 1.0, ©ComAp – May 2011 
InteliPro Communication Brochure 
3-3
CAN bus and RS485 
For wiring of CAN bus communication, the following rules are to be maintained: 
•  Maximal length of the CAN bus depends on the communication speed. For the speed of 
250kbps, which is used on the CAN1 bus (extension modules) and CAN2 bus if it is switched 
to 32C mode the maximal length is 200m. If the CAN2 bus is switched to 8C mode by the 
setpoint Comms settings: CAN Bus Mode, the speed is 50kbps and the maximal length is 
800m.  
•  The bus must be wired in linear form with termination resistors at both ends. No nodes except 
on the controller terminals are allowed. Use cable with following parameters: 
Cable type  Shielded twisted pair 
Impedance 120Ω 
Propagation velocity  >= 75% (delay <= 4.4 ns/m) 
Wire crosscut  >= 0.25mm
2
 
Attenuation (@1MHz)  <= 2dB/100m 
 
 
CAN BUS TOPOLOGY