ABB AC500 PLC Hardware Manual page 1214

System Assembly, Construction and Connection
AC500-eCo > Connection and Wiring
The cable shields must be earthed. See CS31 system bus
on page 1214.
2.5.4.4 CS31 bus
Connection The AC500-eCo Processor Modules can be used as a CS31 bus master. They cannot be used
as a CS31 bus slave. The connection is performed via the serial interface COM1 used as a
CS31 bus (see chapter Serial Interface COM1
Connection of the bus signals: pin 3 and pin 8.
Wiring
Bus line
Construction
Conductor cross section
Recommendation
Twisting rate
Core insulation
Resistance per core
Characteristic impedance
Capacitance between the cores
Terminating resistors
Remarks
Wiring Remarks Shielded cables with PVC core insulation and a core diameter of 0.8 mm can be used up to a
length of ca. 50 m. In this case, the bus terminating resistor is ca. 100 W.
1214
NOTICE!
Risk of EMC disturbances!
Unshielded cables may cause EMC disturbances.
Always use shielded cables and connect the shield at every device.
NOTICE!
Risk of malfunctions!
The pull-up resistors must be used only one time within a bus line.
Use the pull-up resistors only at 1 master.
The ground potential of the interface COM2 is internally connected to the M ter-
minal of the CPU power supply connector.
3ADR010121, 13, en_US
Ä Chapter 2.5.4.4 "CS31 bus"
Ä Chapter 1.2.1.1.3 "Connections" on page 24).
2 cores, twisted, with common shield
> 0.22 mm² (24 AWG)
0.5 mm² corresponds to 0.8 mm
> 10 per meter (symmetrically twisted)
Polyethylene (PE)
< 100 Ω/km
ca. 120 Ω (100 Ω...150 Ω)
< 55 nF/km (if higher, the max. bus length
must be reduced)
120 Ω ¼ W at both line ends
Shielded cables with PVC core insulation and
a core diameter of 0.8 mm can be used up to
a length of ca. 50 m. In this case, the bus ter-
minating resistor is ca. 100 Ω.
2019/04/17