Precautions On Design; Selection - SMC Networks SYJ Series Operation Manual

SYJ Series
Precautions for 3/5 Port Solenoid Valve ① ① ① ①
Be sure to read before handling. Refer to main text for detailed precautions on every series.
Design / Selection
Warning
1. Confirm the specification
Products represented in this instruction manual are
designed only for use in compressed air systems
( including vacuum).
2. Actuator drive
When an actuator, such as a cylinder, is to be driven
using a valve, take appropriate measures (cover
installation or approach prohibition) to prevent potential
danger caused by actuator operation.
3. Intermediate stopping
For 3-position closed center type, it is difficult to make
a piston stop at the required position accurately due to
the compressibility of air. Furthermore, since valves
and cylinders are not guaranteed for zero air leakage, it
may not be possible to hold a stopped position for an
extended period of time. Please contact SMC if it is
necessary to hold a stopped position for an extended
period of time.
4. Effect of back pressure when using a
manifold.
Use caution when valves are used on a manifold,
because an actuator may malfunction due to
back-pressure. For 3-position exhaust center valve or
single acting cylinder, take appropriate measures to
prevent the malfunction by using it with an individual
EXH spacer assembly, a back pressure check valve or
an individual exhaust manifold .
5. Holding of pressure (including vacuum).
Since the valve are subject to air leakage, they cannot
be used for applications such as holding pressure
(including vacuum) in a pressure vessel.
6. Not suitable for use as an emergency
shut-off valve, etc.
The valves listed in this catalog are not designed for
safety applications such as an emergency shutoff valve.
If the valves are used for the mentioned applications,
additional safety measures should be adopted.
7. Release of residual pressure
For maintenance purposes install a system for
releasing residual pressure. Especially in the case of
3-position closed center valve or double check valve
type, ensure that the residual pressure between the
valve and the cylinder is released.
8. Operation in a vacuum condition
When a valve is used for switching a vacuum, take
measures to install a suction filter or similar to prevent
external dust or other foreign matter from entering
inside the valve. In addition, at the time of vacuum
adsorption, be sure to vacuum at all times. Failure to
do so may result in foreign matter sticking to the
adsorption pad, or air leakage causing the workpiece
to drop.
9. Regarding a vacuum switch valve and a
vacuum release valve.
If a non-vacuum is installed in the middle of piping
system having a vacuum, the vacuum condition will not
be maintained. Use a valve designed for use under
vacuum condition.
10. Double solenoid type
When using the double solenoid type for the first time,
actuators may travel in an unexpected direction
depending on the switching position of the valve.
Implement measures to prevent any danger from
occurring when operation the actuator.
11. Ventilation
Provide ventilation when using a valve in a confined
area, such as in a closed control panel. For example,
install a ventilation opening, etc. in order to prevent
pressure from increasing inside of the confined area
and to release the heat generated by the valve.
12.Extended periods
energization
･ If a valve will be continuously energized for an
extended period of time, the temperature of the valve
will increase due to the heat generated by the coil.
This will likely adversely affect the performance of the
solenoid valve and any nearby peripheral equipment.
Therefore, when it is continuously energized or the
energized period per day is longer than the
de-energized period use either: DC specification,
power-saving type. In addition, it is possible to
shorten the energized time by making a valve with an
N.O. (normally open) specification.
･ For applications such as mounting a valve on a
control panel, incorporate measure to limit the heat
radiation so that the temperature will be high when a 3
station manifold.
13. Do not disassemble the product of
make any modifications,
additional machining.
It may cause human injury and/or an accident..
Caution
1. Momentary energization
If a double solenoid valve is operated with momentary
energization, it should be energized for at least 0.1
second. However, depending on the condition of the
secondary load, it should be energized until the cylinder
reaches the stroke and position, since there is a
possibility of malfunction.
2. Leakage voltage
Take note that the leakage voltage will increase when a
resistor is used in parallel with switching element or a
C-R circuit (surge voltage suppressor) is used for
protecting a switching device because of the passing
leakage voltage through the C-R circuit.
The suppressor residual leakage voltage should be as
follows.
DC coil
Should be 3% or less of the rated voltage.
AC coil
Should be 8% or less of the rated voltage.
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No.SYJ3000-OMM0002-A