Wiring; Bus Topology - ABB Advant AC500 Manual

With connecting the terminals 1-2 and 3-4, a pull-up and a pull-down resistor can be activated (see
chapter "Serial interface COM1" for details).

Wiring

Bus line
Construction
Conductor cross section
- recommendation
Twisting rate
Core insulation
Resistance per core
Characteristic impedance
Capacitance between the cores
Terminating resistors
Remarks

Bus topology

A CS31 system bus always contains only one bus master (CPU or coupler) which controls all actions on
the bus. Up to 31 slaves can be connected to the bus, e.g. remote modules or slave-configured CPUs.
Besides the wiring instructions shown below, the wiring and earthing instructions provided with the
descriptions of the modules are valid additionally.
1
2
120
3
Ohms
4
CS31 bus master
e.g. PM581
Master at the
bus line end,
pull-up and
pull-down
activated
bus termination
120 Ohms
Figure: Bus topology for a CS31 system bus at COM1 (bus master at one end of the bus line)
____________________________________________________________________________________________________________
V2
AC500 Hardware
COM1
CS31 system bus
CS31
slave
direct earthing
with clip
on cabinet
steel plate
2 cores, twisted, with common shield
> 0.22 mm² (24 AWG)
0.5 mm² corresponds to Ø 0.8 mm
> 10 per meter (symmetrically twisted)
Polyethylene (PE)
< 100 Ω /km
ca. 120 Ω (100...150 Ω )
< 55 nF/km (if higher, the max. bus length must
be reduced)
120 Ω ¼ W at both line ends
Commonly used telephone cables with PE
insulation and a core diameter of > 0.8 mm are
normally good.
Cables with PVC core insulation and a core
diameter of 0.8 mm can be used up to a length of
ca. 250 m. In this case, the bus terminating
resistor is ca. 100 Ω .
1-36 System data
120
Ohms
CS31
slave
AC500 / Issued: 05.2007