CPU 72x
24.05.2019
page 10
1.4.3
Interfaces
The decentralized processor modules CPU 72x are equipped with one (CPU 725-LT/LTH
and CPU 727-T/TH) or two (CPU 723-T) CAN bus interface and one RS-232 interface.
1.4.3.1
CAN Bus
The connection of the CAN bus is realized via a 5 pole terminal (CAN-, GND and CAN+).
CAN Bus
CPU 723-T
CPU 727-T/TH
CPU 725-LT/LT
H
Galvanic separation
CAN1
logic
No
Yes
1)
Yes
1)
CAN1
RS-232C
Yes
1)
Yes
1)
Yes
1)
CAN1
UC
Yes
1)
Yes
1)
Yes
1)
CAN2
logic
Yes
1)
—
—
CAN2
RS-232C
Yes
1)
—
—
CAN2
UC
Yes
1)
—
—
CAN
ground
Yes
1)
Yes
1)
Yes
1)
Test voltage
560 Vac, 800 Vdc
Bit rates
setting via DIP switch S1 and/or software
Max. bit rate
CAN1
1
Mbit/s
500
kbit/s
500 kbit/s
CAN2
500
kbit/s
—
—
Driver
Level according ISO 11898 standard
1)
simple insulation
Fig.09: CAN bus wiring
Note
At the beginning and the end of the CAN bus network the terminal resistances
RT = 120
are to put in (see chapter "Installation, Startup, and Operation",
5.2.3 CAN Bus Termination).