Field Bus Interface¶
| Interface socket | 5-pin COMBICON |
| Transmission standard | ISO 11898, potential-free |
| Transmission protocol | CANOPEN (CAN), 1 Mbaud max. |
| Transfer rate (baud rate) | 10 kbit/s, 20 kbit/s, 50 kbit/s, 100 kbit/s, 125 kbit/s, 250 kbit/s, 500 kbit/s, 800 kbit/s and 1 Mbit/s, |
The CANOPEN connector has the following pin assignment:
Pin Assignment
| Interface | Pin | Signal | Description | |
|---|---|---|---|---|
Terminal block removed |
Terminal block inserted |
1 | CAN_GND | CAN reference potential |
| 2 | CAN_L | Bus line, receive/transmit line, LOW | ||
| 3 | CAN_SHLD | Shield of the bus line | ||
| 4 | CAN_H | Bus line, receive/transmit line, HIGH | ||
| 5 | NC | Not connected | ||
Attention
:strong:Unused connector!
Make sure that the terminal block is always connected to the terminal base, even if you do not use the interface.
Bus Length
The maximum possible bus length of a CAN network depends on bit rate (transmission rate) and cable type. The sum of all bus segments must not exceed the maximum bus length
| Bit Rate (speed) | Bus Length |
|---|---|
| 1 Mbit/s | 40 m |
| 800 kbit/s | 50 m |
| 500 kbit/s | 100 m |
| 250 kbit/s | 250 m |
| 125 kbit/s | 500 m |
| 62.5 kbit/s | 1000 m |
| 20 kbit/s | 2500 m |
| 10 kbit/s | 5000 m |
Types of Bus Cables
For CANOPEN, only bus cables with characteristics as recommended in ISO 11898 are to be used. The requirements for the bus cables depend on the length of the bus segment. Regarding this, the following recommendations are given by ISO 11898:
| Length of segment [m] | Bus cable (shielded, twisted pair) | Max. baud rate [kbit/s] | ||
|---|---|---|---|---|
| Conductor cross section [mm²] | Line resistance [W/km] | Wave impedance [W] | ||
| 0…40 | 0.25…0.34 / AWG23, AWG22 | 70 | 120 | 1000 at 40 m |
| 40…300 | 0.34…0.60 / AWG22, AWG20 | < 60 | 120 | < 500 at 100 m |
| 300…600 | 0.50…0.60 / AWG20 | < 40 | 120 | < 100 at 500 m |
| 600…1000 | 0.75…0.80 / AWG18 | < 26 | 120 | < 50 at 1000 m |
Bus Terminating Resistors
The ends of the data lines have to be terminated with a 120W bus terminating resistor. The bus terminating resistor is usually installed directly at the bus connector.
CANOPEN interface, bus terminating resistors connected to the line ends
| 1 | CAN_GND |
| 2 | CAN_L |
| 3 | Shield |
| 4 | CAN_H |
| 5 | Data line, shielded twisted pair |
| 6 | COMBICON connection, CANOPEN interface |
DEVICENET interface, bus terminating resistors connected to the line ends
| 6 | DEVICENET power supply |
| 7 | COMBICON connection, DEVICENET interface |
| 8 | Data lines, twisted pair cables |
| 9 | red |
| 10 | black |
| 11 | white |
| 12 | blue |
| 13 | bare |
Note
The earthing of the shield should take place at the switch-gear. Please refer to System Data AC500.