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(3)
Do not use a load that generates surge voltage. If a surge voltage is generated,
discharge may be generated at the contact, possibly reducing the product life.
If driving a load such as a relay that generates a surge voltage.
<Reed>
Use an auto switch with built-in contact protection circuit or use a contact protection box.
<Solid state>
Use a built-in surge absorbing element type device.
(4)
Take precautions when multiple rotary actuator are used close together.
When multiple auto switch rotary actuator are used in close proximity, magnetic field interference may cause
the auto switches to malfunction. Maintain a minimum separation of 40mm between rotary actuator.
The auto switches may malfunction due to the interference from the magnetic fields.
Use of a magnetic screen plate (MU-S025) or commercially available magnetic screening tape can reduce the
interference of magnetic force.
(5)
Pay attention to the internal voltage drop of the auto switch.
<Reed>
1) Auto switch with an indicator light
●
If auto switches are connected in series as shown below, note that there will be a large voltage drop because
of internal resistance in the LED. (Refer to the internal voltage drop in the auto switch specifications.)
[The voltage drop will be “n” times larger when “n” auto switches are connected.]
Even though an auto switch operates normally, the load may not operate.
●
In the same way, when operating under a specified voltage, although an auto switch may operate normally,
the load may not operate. Therefore, the formula below should be satisfied after confirming the minimum
operating voltage of the load.
Supply Internal voltage Minimum operating
voltage drop of auto switch voltage of load
2) If the internal resistance of an LED causes a problem, select an auto switch without an indicator light.
<Solid state / 2-wire type>
3) Generally, the internal voltage drop will be greater with a 2-wire solid state auto switch than with a reed auto
switch. Take the same precautions as in 1).
Also, take note that a 12VDC relay is not applicable.
(6)
Pay attention to leakage current.
<Solid state / 2-wire type>
Current (leakage current) flows to the load to operate the internal circuit even when in the OFF state.
Operating current of load (OFF condition)
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Leakage current
If the criteria given in the above formula are not met, it will not reset correctly (stays ON).
Use a 3-wire switch if this specification will not be satisfied.
Moreover, leakage current flow to the load will be “n” times larger when “n” auto switches are connected in
parallel.
(7)
Ensure sufficient clearance for maintenance activities.
When designing an application, be certain to allow sufficient clearance for maintenance.
(8)
Use the rotary actuator and auto switch in proper combination.
The auto switch is pre-adjusted to operate properly for an auto-switch-capable SMC rotary actuator.
If the auto switch is mounted improperly, used for another brand of rotary actuator or used after changing the
machine installation, the auto switch may not operate properly.
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