Number Of User Data, Bus Cycle Time And Data Security; Replacement Of Modules On The Cs31 System Bus - ABB Advant AC500 Manual

Case b:
Multiple switch-gear cabinets: If potential differences can occur between the switch-gear cabinets, the
capacitive earthing method is chosen in order to avoid circulating currents on the cable shields.
Cabinet 1
COM1
PE
1
2
3
4
120
CS31 bus master
Ohms
e.g. PM581
Cabinet earthing
Cabinet 2
CS31-
Slave
PE
Figure: Earthing concept with several switch-gear cabinets: direct earthing of cable shields when cables
enter the first switch-gear cabinet (containing the master), and capacitive earthing at the modules
Everywhere is valid: The total length of the earthing connections between the shield of the Terminal
Base and the earthing bar must be as short as possible (max. 25 cm). The conductor cross section must
be at least 2.5 mm².
VDE 0160 requires, that the shield must be earthed directly at least once per system.

Number of user data, bus cycle time and data security

See the relevant chapters in the user handbook.

Replacement of modules on the CS31 system bus

____________________________________________________________________________________________________________
V2
AC500 Hardware
CS31 system bus
Earthing bar of cabinet 1
capacitive earthing with 0.1 uF
120
X-type capacitor directly on the
Ohms
cabinet's steel plate
Cabinet earthing
CS31
slave
PE
CS31-
Slave
PE
1-39 System data
direct
earthing
with clip
on cabinet
steel plate
CS31-Systembus
Earthing bar
of cabinet 2
AC500 / Issued: 05.2007