-9-
No.D-
※
S-OMI0002-B
Solid state Auto switch
Design and Selection
Caution
(1) Wiring should be kept as short as possible.
Do not use a cable longer than 100 m.
For long wire lengths, we recommend a ferrite core should be attached to both ends of the cable, to reduce noise.
(2) Do not use a load which generates a surge voltage.
When a load which generates a surge voltage is to be directly driven, operate such as a relay or solenoid, use an auto
switch with built-in surge protection.
(3) Pay attention to the internal voltage drop of the switch.
In general, the internal voltage drop will be greater with a 2-wire solid state auto switch than with a reed type auto
switch.
When auto switches are connected in series, the voltage drop will be "n" times larger when "n" auto switches are
connected.
Even though an auto switch may operate normally, the load may not operate.
Note that a 12 VDC relay is not applicable.
(4) Pay attention to the leakage current.
<2-wire type>
With a 2 wire solid state auto switch, current (leakage current) flows to the load to operate the internal circuit even
when the switch is in the OFF state.
Current to operate load (OFF condition) > Leakage current
If the criteria given in the above formula are not met, the auto switch will not reset correctly (stays ON).
Use a 3 wire type auto switch if this specification cannot be satisfied.
In addition, leakage current flow to the load will be "n" times larger when "n" auto switches are connected in parallel.
(5) The solid state auto switch output will be unstable for 50 ms after power is supplied.
During the time after supplying power, the input device (e.g. PLC, relay) may consider the ON position as OFF output
or the OFF position as ON output.
Please set up the application to consider the signals will be invalid within 50 ms after power is supplied.
Perform a similar setting when using the SMC AHC system (Auto Hand Changing system) MA series.
Wiring
Caution
(1) Do not short-circuit the load.
The auto switch will be damaged if the load is short-circuited.
(2) Avoid incorrect wiring.
1) If connections are reversed on a 2-wire type auto switch, the switch will not be damaged if protected by a protection
circuit, but the switch will always stay in an ON state.
However, it is still necessary to avoid reversed connections, since the switch could be damaged by a load short
circuit in this condition.
2) If connections are reversed (power supply wire + and -) on a 3-wire type auto switch, the switch will be protected by
a protection circuit. However, if the blue wire is connected to the power supply (+) and the black wire is connected
to the power supply (-), the auto switch will be damaged.
(3) Please note the correct stripping direction when removing the cable sheath. The insulator may be split or
damaged depending on the direction used.
Recommended tool:
Description
Part number
Wire stripper
D-M9N-SWY
: For 2-wire type auto switches, a round wire stripper (
2.0) can be used.
