SMC Networks EX12 SCS Series Operation Manual page 14

○Terminating resistor
A terminating resistor should be connected to the end of the main communication cable (the furthest end
from the master) to stabilize communication. An OMRON terminating resistor should be used as shown
below.
Type: SRS1-T
Type: SCN1-TH4T
When connecting the communication cable to the terminal block with terminating resistor, connect the
BDH and BDL communication cables to each terminal.
When the slave at the end of the main communication cable has a T branch type connection, connect
the terminating resistor with a cable longer than the branch cable, so that the terminating resistor
position is the furthest from the master.
○Communication cable
Type
VCTF cable (commercially available cable)
Special flat cable
Type SCA1-4F10 (length 100 m)
○Power supply wiring
The SI unit is a multi power supply type slave. There are two power supplies, for communication and for
the solenoid valves.
(1) Communication power supply
When using VCTF cables for communication cable
The power is supplied from a cable which is separate from the communication VCTF cable to the SI
unit.
When a special flat ribbon cable is used for the communication line.
The communication power supply can be supplied to the SI unit from the special flat ribbon cable.
(2) Power supply for solenoid valves
Connect the power supply 24 VDC +10%/-5%.
suitable for the solenoid valve and SI unit current consumption.
It is possible to supply power to the communication power supply of the SI unit from the power supply
for solenoid valves.
: The power supply should have sufficient power taking into consideration the inrush current.
Caution
The remaining ends of the power supply wires of the special flat ribbon cable should be insulated.
Terminal block with terminating resistor.
This should be used with VCTF cable and the special flat ribbon cable.
Crimped connector with terminating resistor.
This should be used with only the special flat cable.
Vinyl cord VCTF JISC3306
2-core nominal area: 0.75 mm
Conductor resistance (20
Nominal area: 0.75 mm
Ambient temperature: 60
-13-
Specifications
2
(signal cable x 2)
o
C): 25.1 Ω/km
2
x 4 (signal cable x 2, power cable x 2)
o
C or less
Select a power supply and connected cables
No.EX※※-OMC0002-C