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34
Supplying Power to the Slaves
Section 2-3
to Voltage Drop in 2-3-3 Limitations of Communications Cable Power Supply
on page 37. In this case, replace the figure stated for the cable’s resistance
with the conductor resistance of the collective communications power supply
cable in your calculations to verify the allowable cable length.
Note
Depending on the loads connected, multiple power supplies for I/O may gen-
erate electrical noise. Even for a collective power supply, the I/O power supply
should be separated from the communications power supply so that it does
not affect other Slaves. Similarly, a local power supply used for both communi-
cations and I/O should also be kept separate from communications power
supplies.
2-3-2
Using 4-conductor VCTF or Special Flat Cable
Power can be supplied to the Slaves through 4-conductor VCTF or Special
Flat Cable. When a CompoBus/S System is being constructed with 4-conduc-
tor VCTF or Special Flat Cable, the method used to supply power to the
Slaves depends on the type of Slave being used.
The following diagram shows an example of a CompoBus/S System con-
nected with Special Flat Cable that uses each type of Slave. There is no differ-
ence in configuration when 4-conductor VCTF cable is used.
Note
1.
Be sure to insulate unused Special Flat Cable wiring when using a Slave
that requires a local power supply or using an external power supply for
communications in a Slave that requires multiple power supplies.
Master
signal
Power lines
Signal lines
Branch
connector
Special Flat Cable
Power
supply
Network power
supply
Power Signal
I/O
power
supply
Power Signal
Multiple power supplies
For I/O
For Commu-
nications
Power
I/O
power
supply
Power Signal
For I/O
Power
Power
Local power
supply
Connec-
tor with
termina-
tor
H: BD H terminal
L: BD L terminal
+: BS + terminal
–: BS – terminal
: Power terminal V
: Power supply – terminal G
Insulate
unused
wires.
Signal
For Commu-
nications
Common
power sup-
ply for com-
munications
and I/O
+ –
+ –
+ –
+ –
+ –
+ –
– +
–
+
+ –
+ –
+ –
+
H
L
Commu-
nications
power
supply
–
+