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Operating Environment
Warning
1. Never use in an atmosphere of explosive
gases.
The construction of the auto switch is not intended to prevent
explosion. Never use in an atmosphere with an explosive gas
since this may cause a serious explosion.
2. Do not use in an area where a magnetic field
is generated.
The auto switch will malfunction or the magnets inside of a
cylinder will become demagnetized if used in such an environ-
ment. (Please consult with SMC regarding the availability of a
magnetic field resistant auto switch.)
3. Do not use in an environment where the auto
switch will be continually exposed to water.
The switch satisfies the IEC standard IP67 construction (JIS C
0920: waterproof construction). Nevertheless, it should not be
used in applications where it is continually exposed to water
splash or spray. This may cause deterioration of the insulation
or swelling of the potting resin inside switch causing a
malfunction.
4. Do not use in an environment with oil or
chemicals.
Please consult with SMC if the auto switch will be used in an
environment laden with coolant, cleaning solvent, various oils
or chemicals. If the auto switch is used under these conditions
for even a short time, it may be adversely effected by a deteri-
oration of the insulation, a malfunction due to swelling of the
potting resin, or hardening of the lead wires.
5. Do not use in an environment with tempera-
ture cycles.
Please consult with SMC if the switch is used where there are
temperature cycles other than normal temperature changes,
as they may adversely affected the switch internally.
6. Do not use in an environment where there is
excessive impact shock.
<Reed switch>
When excessive impact (300 m/s
2
or more) is applied to a
reed switch during operation, the contact point may malfunc-
tion and generate a signal momentarily (1 ms or less) or cut
off. Please consult with SMC regarding the need to use a solid
state switch in a specific environment.
7. Do not use in an area where surges are gen-
erated.
<Solid state switch>
When there are units (such as solenoid type lifters, high
frequency induction furnaces, motors, etc.) that generate a
large amount of surge in the area around a cylinder with a
solid state auto switch, their proximity or pressure may cause
deterioration or damage to the internal circuit of the switch.
Avoid sources of surge generation and crossed lines.
Wiring
Caution
4. Avoid incorrect wiring.
<Reed switch>
A 24 VDC switch with indicator light has polarity. The brown
lead wire is (+), and the blue lead wire is (–).
1) If connections are reversed, the switch will still operate, but
the light emitting diode will not be illuminated.
Also note that a current greater than the maximum
specified one will damage a light emitting diode and make it
inoperable.
Applicable models: D-A93, A93V
<Solid state switch>
1) Even if connections are reversed on a 2-wire type switch,
the switch will not be damaged because it is protected by a
protection circuit, but it will remain in a normally ON state.
But reverse wiring in a load short circuit condition should be
avoided to protect the switch from being damaged.
2) Even if power supply line (+) and power supply line (–)
power supply line connections are reversed on a 3-wire
type switch, the switch will be protected by a protection
circuit. However, if the power supply line (+) is connected to
the blue wire and the power supply line (–) is connected to
the black wire, the switch will be damaged.
<D-M9
>
D-M9
does not have built-in short circuit protection circuit.
Be aware that if the power supply connection is reversed (e.g.
(+) power supply wire and (–) power supply wire connection is
reversed), the switch will be damaged.
5. When the cable sheath is stripped, confirm
the stripping direction. The insulator may be
split or damaged depending on the direc-
tion.
(D-M9
only)
∗
Stripper for a round cable (ø2.0) can be used for a 2-wire
type cable.
Recommended Tool
Model name
Wire stripper
Model no.
D-M9N-SWY
Series
MY3
Auto Switch Precautions 3
Be sure to read this before handling.
MY3A3B.qxd 06.2.17 9:13 AM Page 47
