1. Never use in the presence of explosive gases.
The construction of our auto switches does not make them
explosion-proof. Never use them in the presence of an
explosive gas, as this may cause a serious explosion.
2. Do not use in an area where a magnetic field is
generated.
Auto switches will malfunction or magnets inside cylinders will
become demagnetized. (Please consult with SMC regarding
the availability of a magnetic field resistant auto switch.)
3. Do not use in environments where the auto
switches will be constantly exposed to water.
Although switches except D-A3/A44/G39/K39 satisfy the
IEC standard IP67 structure (JIS C 0920: anti-immersion
structure), do not use switches in applications where
continually exposed to water splash or spray. Poor insulation
or swelling of the potting resin inside switches may cause
malfunction.
4. Do not use in environments with oil or
chemicals.
Please consult with SMC if auto switches will be used in an
environment with coolants, cleaning solvents, various oils or
chemicals. If auto switches are used under these conditions
for even a short time, they may be adversely affected by
improper insulation, a malfunction due to swelling of the
potting resin, or hardening of the lead wires.
5. Do not use in an environment with temperature
cycles.
Please consult with SMC if switches are to be used where
there are temperature cycles other than normal temperature
changes, as they may be adversely affected internally.
6. Do not use in environments where there is
excessive impact shock.
<Reed switches>
When excessive impact (300 m/s2 or more) is applied to a
reed switch during operation, the contact point may
malfunction and generate or cut off a signal momentarily (1 ms
or less). Please consult with SMC regarding the need to use a
solid state switch depending on the environment.
7. Do not use in locations where surges are
generated.
<Solid state switches>
When there are units (solenoid type lifters, high frequency
induction furnaces, motors, etc.) which generate a large
amount of surge in the area around cylinders with solid state
auto switches, this may cause deterioration or damage to the
switches. Avoid sources of surge generation and crossed lines.
8. Avoid accumulation of iron debris or close
contact with magnetic substances.
When a large amount of ferrous debris such as machining
chips or spatter is accumulated, or a magnetic substance
(something attracted by a magnet) is brought into close
proximity with an auto switch cylinder, it may cause the auto
switches to malfunction due to a loss of the magnetic force
inside the cylinder.

Operating Environment

1. Perform the following maintenance periodically
in order to prevent possible danger due to
unexpected auto switch malfunction.
1) Securely tighten switch mounting screws.
If screws become loose or the mounting position is
dislocated, retighten screws securely after readjusting the
mounting position.
2) Confirm that there is no damage to lead wires.
To prevent faulty insulation, replace switches or repair lead
wires if damage is discovered.
3) Confirm that the green light on the 2-color indicator type
switch lights up.
Confirm that the Green LED is ON when stopped at the set
position. If the Red LED is ON when stopped at the set
position, the mounting position is not appropriate. Readjust
the mounting position until the Green LED lights up.

Maintenance

1. Please consult with SMC concerning water
resistance, elasticity of lead wires, and use at
welding sites.

Other

Warning Warning

Warning
Auto Switches
Precautions 3
Be sure to read before handling.
For detailed precautions on every series, refer to main text.
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