Can Bus Termination; Can Bus Cabling - Eltek Smartpack2 User Manual

2 The Smartpack2 Master Controller

CAN Bus Termination

To ensure a correct bus communication and avoid data reflection, you must always
terminate the CAN bus with two 120 resistors, one at each end of the line (60 bus
impedance).
Smartpack2-based DC power systems are shipped from factory with the CAN bus already
terminated with 120 resistors. The CAN bus termination is implemented with a special
RJ45 plug with built-in 120 end-of-line resistor.
CWUI
(Controller's web-based user interface)
Smartpack2
Master Controller
CAN bus
(twisted-pair
CAT5 cable)
ID Number
I/O Monitor2
81
Alarm Outputs NC-C-NO
Config. Inputs
Flatpack2
DC Power System
Figure 3 Example of CAN bus addressing and termination in a Flatpack2 power system with
Smartpack2-based control system and several monitors connected the CAN bus
When connecting more CAN nodes to the bus, you have to remove the CAN bus
termination plug from one of the CAN bus ends, and plug it in one of the CAN ports on the
last connected CAN node.

CAN Bus Cabling

In addition to the two dedicated wires for communication, the CAN bus multi-wire cable
must integrate wires for the CAN power supply and other signals. In standard industrial
environments, the CAN bus can use standard cabling without shielding or twisted pair
wiring. If very low interference (EMI) is required, a CAT-5 twisted-pair cable is
recommended.
8
Ethernet cable (LAN)
Smartpack2
Basic Controller
1
01
Internal System Monitoring
I/O Monitor
82
Temp, Fan Speed Mon & Ctrl
Alarm Outputs NC-C-NO
Config. Inputs
User's Guide Smartpack2 Master Controller
120
End-of-Line
Resistor
Flatpack2 HE
Rectifiers
02 n
Battery Monitor
33
Battery string #1
Load Monitor
120
End-of-Line
49
Resistor
Shunts
Current Monitoring
Sense Inputs
Fuses
Fuse Monitoring
Configurable Inputs
350020.013, Issue 2.0, 2014 Jan