IMO VXSM75-1 Instruction Manual page 22

(1) Analog input terminals (13, 12, C1, 11)
a. Because weak analog signals are
handled, these signals are especially
susceptible to external noise effects.
Route the wiring as short as possible
(within 20 m) and use shielded cables. In
principle, ground the shield of the
shielded cable; if effects of external
inductive noises
connection to terminal 11 may be
effective.
b. Use twin contacts relay for weak signals
if relay is used in the circuit. Do not add
a contact to terminal 11.
c. When the inverter is connected with an
external device outputting the analog
signal, a malfunction may be caused by
electric noise generated by the inverter
according to some type of the circuit of
the device. If this happens, connect a
ferrite core or capacitor to the device
outputting the analog signal.
Fig. 2-3-3
WARNING
If the control cables touch the live part
of the main circuit, the insulation
sheath of the control cable, insulation of
which is not reinforced, may be broken to
cause a high voltage of the main circuit to be
fed to the control signal. This is banned in
the low voltage directive models for Europe.
Electric shock could occur.
CAUTION
Electric noise may be generated by the
inverter, motor or wiring. Take care of
malfunctions of the nearby sensors and devices.
An accident could occur.
Installation and Connection
are considerable,
(2) Digital input terminals (FWD, REV, X1
through X5, P24)
a. Generally the digital input terminals
(FWD, REV, X1-5) are turned on or off in
relation to the P24 terminal.
b. To use contact input, use a reliable
contact free from poor contact.
(3) Transistor output terminals (Y1E-Y2E,
CMC)
a. Circuit configuration shown in Table 2-3-
2 for transistor output is adopted. Take
care of the polarity of the external power
supply.
b. To connect a control relay, connect a
surge absorbing diode across the coil of
the relay.
Fig. 2-3-4 Countermeasure against electric noise
(example)
(4) Others
a. Route the wiring of the control terminals
as far from the wiring of the main circuit
as possible. Otherwise electric noise
may cause malfunctions.
b. Fix the control cables inside the inverter
to keep them away from the live parts of
the main circuit (such as the terminal
block of the main circuit).
2-8