OPERATION MANUAL CompoBus/S

Supplying Power to the Slaves Section 2-3
34
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 generate
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 communications
and I/O should also be kept separate from communications power
supplies.
2-3-2 Using 4-conductor VCTF or Special Flat Cable
Master
signal
H
L
Power
supply
+
–
H: BD H terminal
L: BD L terminal
+: BS + terminal
–: BS – terminal
+
: Power supply + terminal V
– : Power supply – terminal G
Power lines
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-conductor
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 connected
with Special Flat Cable that uses each type of Slave. There is no difference
in configuration when 4-conductor VCTF cable is used.
Power Signal
Network power
supply
Signal lines
Branch
connector
+ – + – + –
Power Signal
For Communications
For I/O
Power
+ –
I/O
power
supply
Special Flat Cable
Power Signal
For Communications
For I/O
Power
+ – – + + –
Communications
power
supply
+ –
I/O
power
supply
Multiple power supplies
Insulate
unused
wires.
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.
Power
+ –
+ –
Common
power supply
for communications
and I/O
Signal
Local power
supply
Connector
with
terminator