OPERATION MANUAL CompoBus/S

Supplying Power to the Slaves Section 2-3
Voltage Drops Due to
Wiring
Power supply
(24 V DC)
Arrangement of Power
Supplies
Power supply
(24 V DC)
When dividing the Slaves into groups to supply power, connect the groups
using a standard relay terminal like the one shown in the following diagram.
Insulate unused wires.
Insulate
unused
wires.
Power supply B
(24 V DC)
Relay terminal
Communications power + (BS +, brown)
Communications data high (BD H, black)
Communications data low (BD L, white)
Communications power – (BS –, blue)
When components such as circuit protectors, contactors, connectors, and
fuses are incorporated in the wiring, the internal resistance and contact resistance
of these components can have an effect on voltage drops as well as the
conductor resistance of the cable itself. When designing the wiring, attention
must be paid to these resistance values as well.
CP (circuit protector,
breaker, etc.)
Cable resistance Contact resistance
of relays, contactors,
contacts, etc.
Connector
Slave
r 0 r 1 r 2 r 3 r 4
Wiring must be designed to
provide a stable operating
voltage to the terminal
Slave as well.
Note The resistance and allowable current varies according to the cross section,
material, and structure of the cable, as well as the ambient temperature.
When designing the wiring and selecting the cables to be used, refer to the
specifications stated by the cable manufacturer.
In systems in which the I/O power supply for the entire system is supplied, it is
necessary to take into account the power consumption of each device and
load. Cables selected for use with the terminal Slave or load should also keep
voltage fluctuations within the allowable range. Care must also be taken to
ensure that the total current on the lines is within the range of the permissible
current of the cable, and that the capacity of the power supply is adequate.
I 1
Slave Slave Slave
Load
∆E 1 ∆E 2 ∆E 3
I 2
I 3
Slave
Load Load
Wiring must be designed to
provide a stable operating
voltage to the last load as
well.
Examine the following points when deciding whether to supply I/O power for
the entire system from a single source, or to install multiple power supplies.
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