____________________________________________________________________________________________________________
V2
AC500 Hardware
1-37 System
data
AC500 / Issued: 05.2007
CS31 system bus
CS31
Sh
ie
ld
BU
S
2
BU
S
1
Sh
ie
ld
BU
S
2
BU
S
1
slave
CS31
slave
120
Ohms
120
Ohms
direct
earthing
with clip
1
2
3
4
COM1
Master within
the bus line,
pull-up and
pull-down
activated
CS31 bus master
e.g. PM581
Figure: Bus topology for a CS31 system bus at COM1 (bus master within the bus line)
CS31 system bus
CS31
Shield
BU
S
2
BU
S
1
slave
CS31
CS31
Shield
BU
S
2
BU
S
1
slave
1
2
3
4
120
Ohms
COM1
CS31 bus master
e.g. PM581
Master at the
bus line end,
pull-up and
pull-down
activated
bus termination
120 Ohms
system bus
WRONG!
Spur lines are not
allowed.
RIGHT!
Bus line is looped through
from module to module.
Figure: Wiring with spur lines is not allowed