Examples Of Improper Remote I/O Wiring; Table 7-4 Correct And Incorrect Remote I/O Wiring - Hitachi S10VE User Manual

7.7.2 Examples of improper remote I/O wiring

Wiring the remote I/O cables in any of the incorrect ways shown in Table 7-4 can distort the waveform of the
signal on the lines, causing communication errors. Take care to wire the cables correctly.
1
Termination
RI/O-1
■ A maximum of 12 units can be connected per line, and you must terminate the line at both ends.
■ The unused port of the RI/O-IF module in the CPU unit must be terminated with 150Ω resistance.
1
1
RI/O-1
CPU unit
1
RI/O-1
1
RI/O-1
1
RI/O-1
● To avoid malfunction, set a terminating resistance (150Ω) at any RI/O-IF module ports to which a
remote I/O cable will not be connected. This prevents external noise from entering the system.

Table 7-4 Correct and incorrect remote I/O wiring

CPU unit PI/O unit
RI/O 2 1 RI/O
Unused
Termination (150Ω)
PI/O unit CPU unit
RI/O 2 RI/O
1
Termination
Termin
RI/O-1
■ There are no restrictions in terms of the positioning of the CPU unit.
CPU unit PI/O unit
RI/O 2 1 RI/O
PI/O unit
RI/O RI/O
2 1
RI/O-2
CPU unit PI/O unit
RI/O RI/O
2 1
TB
TB
■ Connect cables directly, not via a terminal block.
CPU unit PI/O unit
RI/O 2 1 RI/O
PI/O unit
2 1 RI/O
PI/O unit
1 RI/O
2
Termin
RI/O-2
PI/O unit
2 1 RI/O
■ Do not use a branching connection.
PI/O unit
RI/O
2 1
■ Do not form a closed loop.
PI/O unit
RI/O
2 1
PI/O unit
2 1 RI/O
■ Do not mix cable types in a given line.
Notice
7-15
PI/O unit
2 1 RI/O 2
Termination
PI/O unit
2 1 RI/O 2
Termin
PI/O unit
2 1 RI/O 2
PI/O unit
RI/O
2 1 2
2
2
7. Wiring