2 Installation and Setting
- 4 -
2)
CAN bus connection
The following figure shows the CAN bus connection. The shielded twisted pairs are
recommended for CAN bus connection. The two sides of the bus are respectively
connected with two 120-Ω terminal matching resistors to prevent signal reflection.
Single-point grounding is generally used for the shield.
120
Ω
*
Built-in jumper
can be enabled on
the CANlink card.
*
CANL
CANH
CANH
Four-core STP
CGND
Avoid sharing the common
ground between the grounding
cable and large-power devices.
Do not remove too much of the shielding layer.
CANL CANH
CGND
Servo drive
CANL
120
Ω
*
Built-in jumper can
be enabled on the
CANlink card.
*
+24V
PLC with CAN card
Slave station
CANL
CANH
CGND
+24V
PLC with CAN card or remote
extension module
24 V power
+
-
Master station
CANL
CANH
CGND
AC drive with CAN card
Slave station
Slave station
[Note 1]
[Note 2]
[Note 1] Select a CANlink interface card according to the PLC type.
[Note 2] Select a CANlink interface card according to the AC drive type.
Figure 2-3
CAN bus connection
NOTE
◆
Inovance's
PLC and MDCAN2 are equipped with built-in resistors, which
can be enabled by the DIP switch.
3)
CAN bus transmission distance
The CANopen bus transmission distance is directly related to the baud rate and
communication cable. The following table describes the relationship between the
maximum bus length and the baud rate.
Table 2-2
Relationship between the bus length and the baud rate
Baud Rate (bps)
1 M
500 K
250 K
125 K
Bus Length (m)
30
80
150
150
4)
DIP switch
DIP switch S1 of MD38CAN2 composes a 2-digit DIP switch for setting the CAN bus
termination resistor. It is recommended that the termination resistor be used at two
sides of the network topology structure. The switch on the ON position indicates
1,
and
indicates 0 otherwise.
Table 2-3
Setting the termination resistor for MD38CAN2
DIP Switch No.
Termination Resistor
1
2
0
0
Disconnected
1
1
Connected
