Selection
Caution
1. Leakage voltage
Particularly when using a resistor in parallel with a switching
element and using a C-R element (surge voltage suppressor)
to protect the switching element, take note that leakage cur-
rent will flow through the resistor, C-R element, etc., creating
a possible danger that the valve may not turn off.
1) Take steps to ensure that there are no problems such as
abnormal voltage drops or insufficient capacity associated
with the signal power supply used to drive the solenoid
valve.
2) Make sure the leakage current flowing through the solenoid
valve when power is not being supplied is 0.1 mA or less. If
there the leakage current is larger than this, take
appropriate measures such as connecting a bleeder
resister (models with power-saving circuit).
3) An attenuation function is provided to reduce voltage
surges produced by the solenoid valve. However, the
controller should be equipped with protection against
voltage surges as some residual surge voltage may still
reach external components.
Series
VDW30/40
Specific Product Precautions 1
Be sure to read before handling. Refer to back cover for Safety Instructions, “Handling
Precautions for SMC Products” (M-E03-3) for Fluids Control 2 Port Valves Precautions,
and Series VDW in Best Pneumatics No. 7 for Specific Product Precautions.
Caution
2. Connection of piping to products
• When connecting piping to a product, refer to its instruction
manual to avoid mistakes regarding the supply port, etc.
• Do not apply external force to the coil when holding it to con-
nect piping, as the tube may deform.
• When attaching fittings to a solenoid valve, do not use fit-
tings that do not conform to the quick fastener standard.
• Handle with care when attaching fittings because the appli-
cation of excessive stress to the quick fastener portion could
damage the body.
Piping
Mounting
Warning
1. When the valve is secured using an insert nut (part
number suffix “-N”), handle with care during
installation because the application of excessive
stress to the body could damage it (appropriate
tightening torque: 0.8 to 1.0 N·m).
Warning
1. During use, deterioration of the tubing or damage
to the fittings could cause tubes to come loose
from their fittings and thrash about.
To prevent uncontrolled tube movement, install protective
covers or fasten tubes securely in place.
2% or less of rated voltage
DC coil
2. Low temperature operation
1) The valves can be used up to an ambient temperature of
–10
°
C, however take measures to prevent solidification of
impurities or freezing, etc.
2) When using valves for water application in cold climates,
first stop the water supply/discharge of the pump, etc., and
then take measures to prevent freezing such as draining
water in pipe. When heating by steam, be careful not to ex-
pose the coil portion to steam. Also, please take measures
to prevent freezing such as heating the body.
Warning
1. Fluid quality
In the case of water
The use of a fluid which contains foreign matter can cause
problems such as malfunction and seal failure by promoting
wear of the valve seat and armature, and by sticking to the
sliding parts of the armature, etc. Install a suitable filter
(strainer) immediately upstream from the valve. In general, a
mesh of about 50 to 100 is a guideline for the filter.
When using ordinary tap water, scaling and sludge from
substances in hard water such as calcium and magnesium
can cause solenoid valves to malfunction. It is therefore
necessary to install a water softener to remove such
substances and a filter (strainer) immediately before the
solenoid valve.
In the case of air
Please use ordinary compressed air where a filter of 40
µ
m or
less is provided on the inlet side piping. (Except dry air)
Recommended Piping Conditions
1. When connecting tubes
using One-touch fittings,
provide some spare tube
length as shown in Fig. 1,
recommended piping con-
figuration.
Also, do not apply external
force to the fittings when bind-
ing tubes with bands, etc. (see
Fig. 2.)
Unit: mm
Tube size
Mounting pitch
A
Nylon tube
Soft nylon tube Polyurethane tube
56 or more
84 or more
112 or more
140 or more
30 or more
39 or more
58 or more
70 or more
26 or more
39 or more
52 or more
69 or more
Straight
portion length
ø4
ø6
ø8
ø10
20 or more
30 or more
40 or more
50 or more
Switching element
OFF
C
R
Leakage current
Valve
Recommended
Unacceptable
Fig. 2 Binding tubes with bands
Straight
portion
Mounting
pitch
A
Fig. 1 Recommended piping
configuration
Power supply
Leakage voltage
6
VDW30-Info.qxd 10.5.31 10:51 AM Page 6
Courtesy of Steven Engineering, Inc.-230 Ryan Way, South San Francisco, CA 94080-6370-Main Office: (650) 588-9200-Outside Local Area: (800) 258-9200-www.stevenengineering.com
