CAN light-isolated repeater Manual

                                    ECANG is CAN repeaters light-isolated repeater is used to achieve the isolation and relay to enlargement of CAN signal. When CAN communication distance is longer than 5 km, this repeater is required in order to realize signal amplification and extend communication distance. The products have characteristics such as high-speed, two-way extending, automatically switching the flow of signals and automatically adaptation of baud rate. It can extend 10km(4800bps),5km(9600bps) of communication distance in 2 ways. All their industrial-grade devices are anti-static and anti-

                              lightning; make them work stably in the poor industrial environment.

                              Technical details:

                              relay range is up to 10km(4.8Kbps)、5km(9.6Kbps)、3km(19.2Kbps)、       2km(38.4Kbps)、1200m(57.6Kbps)、600m(115.2Kbps)、300m(250Kbps)、150m(500Kbps

                              light-isolated voltage: 1000 VDC (up to 3000 VDC, statement required when ordering)

                              communication rate: normal mode:0~500Kbps Adaptive, enhanced-driving mode: 0~100Kbps adaptive 

                              110 CAN transceivers can be linked to bus.

                              work way: Two-wire half-duplex transparent transmission, zero-delayed two-way automatic switching of signal

                              ★ the unique enhanced drive circuit, the voltage can be doubled when outputting signal, can be used for long-distance transmission of smaller communication line

                              ★ slope-limited driver, to minimize electromagnetic interference, and can reduce the reflection caused by the not match of transmission line terminal.

                              ★ transmission lines: Cross-sectional area is 0.75 mm2 above, the twisted pair with 120 Ohm impedance. The cross-sectional area of twisted pair should be more than 1.5 mm2 and the capacitance between line should be less than 60 pf / m when 

                              the length of lines are more than 1km

                              interface protection:
                              CAN port: Anti-lightning and anti-surge protection, repeatability surge capacity: Ipp = 100A (10/700us, 4KV)
                              standards: ITU-TK20/21, VDE 0433.
                              Power port: 500 W TVS anti-lightning protection, anti-polarity of power protection.

                              external 5 V, 1W DC power supply, the internal DC / DC isolated power supply

                              ★ temperature: -20 ℃ ~ +75 ℃

                              ★ Dimensions: 85 × 55 × 25

                              ★ installation: installation of 35 mm standard rails and the bolt hole

                              ★ Weight: 100 g

                              Products’ shape and definition of terminal signals:

                              Definition of connection terminal’s signal

                               CAN terminal(left)

                              CAN terminal and power terminal(right)






                              CAN high


                              CAN high


                              CAN low


                              CAN low


                              Signal ground


                              External connect the anode of 5V power supply


                              Not be used


                              Power ground(CAN signal ground)


                              Not be used


                              Not be used


                              Not be used


                              Not be used


                              Not be used


                              Not be used


                              Not be used


                              Not be used


                              ECANG-formed relay communication network:


                                    The 120 Ω resistances in the picture is terminal resistance. They are to prevent the signal reflection in the line. Users must connect the above resistance in the line’s two terminals as the map shown. Turn the terminal resistance setting switches K1 and K2 of ECANG to "R" (connect terminal resistances)

                              。The settings of K3 switch: Bus is divided into two sections by repeaters. When the length of each section is less than 5 km , turn the K3 to "normal" position. When the Length of each section is more than 5 km , turn K3 to the "drive-enhanced " location, witch will make relay output double voltage signal, but cause greater signal reflection at the same time. Particularly when several repeaters are in series.

                              The "normal" way is recommended.


                              1, The cut-off size of communication lines is often overlooked by the users. Because the CAN receiver’s effective level (0.8 V) is higher than the RS485 receiver’s (0.2 V), the requirement of communication lines’ cross-sectional area is high. And farther the communication distance is, the greater the cross-sectional area should be. The twisted pair best be the one whose impedance is 120 Ohm, and the capacitance between line is less than 60 pf / m. The following table is the twisted pair’s minimum cross-sectional area of different communication distance:

                              Communication distance(km)




                              Cross-sectional area of twisted pair (mm2)





                                    These are the cross-sectional areas of communication lines witch are required by the Fourstar’s CAN interface product with unique driven-enhanced circuit. The communications lines’ cross-sectional area may be doubled from the table values as for other companies’ CAN interface products.

                              2, In order to prevent the common mode voltage of CAN interface beyond the permitted range witch would impact the reliability of communication or even damage interfaces, you can use a low resistance wire whose cross-sectional area is 1 mm2 to connect the signal ground "SG" and the power ground "GND" of ECANG with the CAN nodes’ signal ground on their respective side. This will remove the groune of each node on the network..

                              3. For the setting of terminal resistance, the role of terminal resistance is to eliminate the waveform distortion caused by the reflection of signal in the communication lines. You should connect the terminal resistance into the start and end of the circuit. And turn the terminal resistance setting switches K1 and K2 of ECANG to "R" (connect terminal resistances). But terminal resistance is not acceptable for other CAN nodes in the circuit.

                              4, when there are several repeaters in series in the bus, there will certainly be delay of signal. Thus the length of each section of bus witch was divided by the repeater is no more than the 70 percent of corresponding baud rate’s maximum length. If the largest communications distance is 5 km when baud rate is 9600 bps, the maximum length of each bus section between the two ends of repeater can’t exceed 3500 m after the repeater is added. Try to set K3 in "normal" working methods.

                              Three main tips for using:

                               ① guarantee the cross-sectional area of twisted pair is no less than 1.5 mm2 (per km one-way resistance is no more than 12 Ohm);

                               ② the length of each bus section between the two ends of repeater is on more than 5km (two-wire resistance is no more than 120 Ohm);

                               ③ turn K3 to "normal" position, make repeaters work in the CAN standard way.

                              5, the second-line half-duplex communication is used for these products, non-delay transparent transmission, compatible with any upper agreements.