Solid State Relays Common Precautions

Solid State Relays Common Precautions
●For precautions on individual products, refer to "■Precautions" in individual product information.
CAUTION
Touching the charged section is likely to cause
electric shock. Do not touch the SSR terminal
section (the charged section) when the power
supply is ON. For SSRs with terminal covers, be
sure to attach the cover before use.
The SSR and heat sink will be hot and are likely to
cause burns. Do not touch the SSR or the heat sink
either while the power supply is ON, or
immediately after the power is turned OFF.
The internal snubber circuit is charged and will
cause electric shock. Do not touch the SSR load
terminal immediately after the power is turned
OFF.
Solid State Relays Common Precautions
Electric shock is likely to result. Be sure to
conduct wiring with the power supply turned OFF.
SSRs may occasionally explode. Do not apply a
short-circuit current to the load side of an SSR.
To protect against short-circuit accidents, be sure
to install a protective device, such as a
quick-break fuse etc. on the power supply line.
Safety Cautions
OMRON constantly strives to improve quality and reliability. SSRs,
however, use semiconductors, and semiconductors may
commonly malfunction or fail. Short-circuit failures represent the
main failure mode and can result in an inability to shut OFF the
load. Therefore, for fail-safe operation of control circuits that use
SSRs, do not use circuits that shut OFF the load power supply only
with an SSR, but rather also use circuits with a contactor or breaker
that shuts off the load when the SSR fails. In particular, it may not
be possible to ensure safety if the SSRs are used outside the rated
ranges. Therefore, always use the SSRs within the ratings.
When using an SSR, always design the system to ensure safety
and prevent human accidents, fires, and social harm in the event
of SSR failure. System design must include measures such as
system redundancy, measures to prevent fires from spreading,
and designs to prevent malfunction.
1. Do not apply voltage or current in excess of the ratings to the
terminals of the SSR. Doing so may result in failure or burn
damage.
2. Heat Radiation
 Be careful with the increase in ambient temperature caused
by self-heating. Mount a fan etc. to provide a sufficient air
ventilation especially in case of internal mounting.
 Mount the SSR following the specified mounting orientation.
The abnormal heat generation from the body may cause
output elements to short or may cause burning.
3. Perform correct wiring following the precautions below.
Improper wiring may lead to abnormal heating resulting in burn
damage to the SSR once the power is supplied.
 Use a suitable wire according to the load current. Otherwise
the abnormal heating of the wire may cause burning.
4. Operating Conditions
 Designate the load within the rated range. Otherwise it may
result in faulty operation, malfunction, or burning.
 Use a power supply within the rated frequency range.
Otherwise it may result in faulty operation, malfunction, or
burning.
5. Do not transport the SSR under the following conditions.
Failure, malfunction, or deterioration of performance
characteristics may occur.
 Conditions under which the SSR will be exposed to water
 High temperatures or high humidity
 Without proper packing
6. Operating and Storage Environment
Do not use or store the SSR in the following environments.
Doing so may result in damage, malfunction, or deterioration
of performance characteristics.
 Do not use or store in environments subject to exposure
to sunlight.
 Do not use in environments subject to temperatures
outside the range specified individually.
 Do not use in environments subject to relative humidity
outside the range of 45% to 85% RH, or in locations
subject to condensation as the result of severe changes
in temperature.
 Do not store in environments subject to temperatures
outside the range specified individually.
 Do not use or store in environments subject to corrosive
or flammable gases.
 Do not use or store in environments subject to dust, salt,
or iron dust, or in locations subject to salt damage.
 Do not use or store in environments subject to shock or
vibration.
 Do not use or store in environments subject to exposure
to water, oil, or chemicals, or in environments subject to
exposure to rain and water splashes.
 Do not use or store in environments subject to high
temperature or high humidity.
C-340
Solid State Relays Common Precautions
Precautions for Correct use
●Before Using SSR
1. The SSR in operation may cause an unexpected accident.
Therefore it is necessary to test the SSR under the variety of
conditions that are possible.
For example, as for the characteristics of the SSR, it is
necessary to consider differences in characteristics between
individual SSRs.
2. The ratings in this catalog are tested values in a temperature
range between 15°C and 30°C, a relative humidity range
between 25% and 85%, and an atmospheric pressure range
between 88 and 106 kPa. It will be necessary to provide the
above conditions as well as the load conditions if the user
wants to confirm the ratings of specific SSRs.
2. Inductive Noise
Do not wire power lines alongside the input lines. Inductive
noise may cause the SSR to malfunction. If inductive noise is
imposed on the input terminals of the SSR, use the following
cables according to the type of inductive noise, and reduce the
noise level to less than the must release voltage of the SSR.
Twisted-pair wire: For electromagnetic noise
Shielded cable: For static noise
A filter consisting of a combination of capacitor and resistor will
effectively reduce noise generated from high-frequency
equipment.
■Input Circuit
Filter
High-frequency
device
●Input Noise
SSRs need only a small amount of power to operate. This is why
the input terminals must shut out electrical noise as much as
possible. Noise applied to the input terminals may result in
malfunction. The following describes measures to be taken
against pulse noise and inductive noise.
1. Pulse Noise
A combination of capacitor and resistor can absorb pulse
noise effectively. The following is an example of a noise
absorption circuit with capacitor C and resistor R connected to
an SSR incorporating a photocoupler.
Pulse width
R
C
Note: R: 20 to 100 Ω
C: 0.01 to 1 μF
●Input Conditions
1. Input Voltage Ripples
When there is a ripple in the input voltage, set the input
voltage so that the peak voltage is lower than the maximum
operating voltage and the root voltage is above the minimum
operating voltage.
Peak voltage
Root voltage
0V
2. Countermeasures for Leakage Current
When the SSR is powered by transistor output, the must
release voltage may be insufficient due to leakage current
while power is OFF. To counteract this, connect bleeder
resistance as shown in the diagram below and set the bleeder
resistance so that VR is half of the release voltage or less.
Pulse voltage
Pulse width (s)
The value of R and C must be decided carefully. The value of
R must not be too large or the supply voltage (E) will not be
able to satisfy the required input voltage value. The larger the
value of C is, the longer the release time will be, due to the
time required for C to discharge electricity.
10
10
00
6
4
0
2
10
00
1
0
10
00
0.2
0.01
20

0
10
00

0
0.0
01
40
0.0
1
0.0
01
33
0.0
0.1
1
33
0.1
0.02

33
0.6
0.4
0.06
0.04

33
0.1
1
1
F
F
F
F
F
F
F
F
60
100
200
400 600 1000
Pulse voltage (V)
Note. For low-voltage models, sufficient voltage may not be applied to the
SSR because of the relationship between C, R, and the internal
impedance. When deciding on a value for R, check the input
impedance for the SSR.
Bleeder resistance
The bleeder resistance R can be obtained in the way shown
below.
E
R≤
IL−I
E : Voltage applied at both ends of the bleeder resistance =
half of the release voltage of the SSR
IL : Leakage current of the transistor
I : Release voltage of SSR
The actual value of the release current is not given in the
datasheet and so when calculating the value of the bleeder
resistance, use the following formula.
Minimum value of release voltage
Release current for SSR =
Input impedance
For SSRs with constant-current input circuits, calculation is
performed at 0.1 mA.
The calculation for the G3M-202P DC24 is shown below as an
example.
1V
Release current I=
=0.625 mA
1.6 kΩ
1V×1/2
Bleeder resistance R=
IL−0.625 mA
C-341
Solid State Relays Common Precautions
There is variation in the input impedance of SSRs. Therefore, do
not connect multiple inputs in series. Otherwise malfunction may
occur.
Load
●Connecting to the Input Side
Solid State Relays Common Precautions
3. ON/OFF Frequency
An SSR has delay times called the operating time and release
time. Loads, such as inductive loads, also have delay times
called the operating time and release time. These delays must
all be considered when determining the switching frequency.
4. Input impedance
In SSRs which have wide input voltages (such as G3CN and
G3TB), the input impedance varies according to the input
voltage and changes in the input current.
For semiconductor-driven SSRs, changes in voltage can
cause malfunction of the semiconductor, so be sure to check
by the actual device before usage.
See the following examples.
Input current (mA)
Input impedance (k)
Input impedance (Example)
G3CN
T25°C
20
0
8
●DC Switching SSR Output Noise Surges
When an L load, such as a solenoid or electromagnetic valve, is
connected, a diode that prevents counter-electromotive force. If
the counter-electromotive force exceeds the withstand voltage of
the SSR output element, it could result in damage to the SSR
output element. To prevent this, insert the element parallel to the
load, as shown in the following diagram and table.
Load
SSR
INPUT
As an absorption element, the diode is the most effective at
suppressing the counter-electromotive force. The release time
for the solenoid or electromagnetic valve will, however, increase.
Be sure to check the circuit before use. To shorten the time,
connect a Zener diode and a regular diode in series. The release
time will be shortened at the same rate that the Zener voltage
(Vz) of the Zener diode is increased.
Talbe 1. Absorption Element Example
6
Input current
Absorption
element
4
3
2
Input impedance
Effectiveness
Diode
Diode +
Zener diode
Varistor
CR


r
×
Solid State Relays Common Precautions
1.5
1
2
3
4
6
8
10
■Output Circuit
20
30
Input voltage (V)
●AC Switching SSR Output Noise and Surges
 In case there is a large voltage surge in the AC current being
used by the SSR, the RC snubber circuit built into the SSR
between the SSR load terminals will not be sufficient to
suppress the surge, and the SSR transient peak element
voltage will be exceeded, causing overvoltage damage to the
SSR.
 Only the following models have a built-in surge absorbing
varistor: G3NA, G3S, G3PA, G3NE, G3PH, G3DZ (some
models), G3RZ, and G3FM. When switching an inductive load
with any other models, be sure to take countermeasures
against surge, such as adding a surge absorbing element.
 In the following example, a surge voltage absorbing element
has been added.
(Reference)
1. Selecting a Diode
Withstand voltage = VRM ≥ Power supply voltage × 2
Forward current = IF ≥ load current
2. Selecting a Zener Diode
Zener voltage = VZ < SSR withstand voltage
− (Power supply voltage + 2 V)
Zener surge power =
PRSM > VZ × Load current × Safety factor (2 to 3)
Note. When the Zener voltage is increased (Vz), the Zener diode capacity
(PRSM) is also increased.
●AND Circuits with DC Output SSRs
Varistor
Use the G3DZ relay for the following type of circuit.
Load
Input
Varistor
Output
Input of the
logic circuit
Select an element which meets the conditions in the following
table as the surge absorbing element.
Voltage
Varistor voltage
100 to 120 VAC
240 to 270 V
200 to 240 VAC
440 to 470 V
380 to 480 VAC
820 to 1,000 V
Surge resistance
1,000 A min.
●Output Connections
Do not connect SSR outputs in parallel. With SSRs, both sides of
the output will not turn ON at the same time, so the load current
cannot be increased by using parallel connections.
C-342
●Self-holding Circuits
Self-holding circuits must use mechanical relays. (SSRs cannot
be used to design self-holding circuits.)
Solid State Relays Common Precautions
●Selecting an SSR for Different Loads
The following provides examples of the inrush currents for
different loads.
AC Load and Inrush Current
Solenoid
Incandescent
lamp
Load
Approx. 10 to
15 times
Relay
Approx. 5
Approx. 2
to 10
to 3 times
times
Capacitor
Approx.
20 to 50
times
Resistive
load
1
Normal current
Inrush current
Inrush current/ Approx. 10
Normal current
times
Motor
Waveform
4. Transformer Load
When the SSR is switched ON, an energizing current of 10 to
20 times the rated current flows through the SSR for 10 to 500
ms. If there is no load in load side circuit, the energizing
current will reach the maximum value. Select an SSR so that
the energizing current does not exceed half the inrush current
resistance of the SSR.
5. Half-wave Rectifying Circuit
AC electromagnetic counters or solenoids have built-in diodes,
which act as half-wave rectifiers. For these types of loads, a
halfwave AC voltage does not reach the SSR output. For
SSRs with the zero cross function, this can cause them not to
turn ON. Two methods for counteracting this problem are
described below.
1. Connect a bleeder resistance with approximately 20% of the
SSR load current.
Bleeder resistance
Load
2. Use SSRs without the zero cross function.
6. Full-wave Rectified Loads
AC electromagnetic counters and solenoids have built-in
diodes, which act as full-wave rectifiers. The load current for
these types of loads has a rectangular wave pattern, as shown
in the following diagram.
Heater load
Temperature
Controller
(pulse-voltage-output)
Load
250
200
150
Non-repetitive
100
Repetitive
50
0
10
30 50 100
300 500 1,000
5,000
Energized time (ms)
3. Motor Load
When a motor is started, an inrush current of 5 to 10 times the
rated current flows and the inrush current flows for a longer
time than for a lamp or transformer. In addition to measuring
the startup time of the motor or the inrush current during use,
ensure that the peak value of the inrush current is less than
half the inrush current resistance when selecting an SSR. The
SSR may be damaged by counterelectromotive force from the
motor. Be sure to install overcurrent protection for when the
SSR is turned OFF.
Circuit current
wave pattern
Accordingly, AC SSRs use a triac (which turns OFF the
element only when the circuit current is 0 A) in the output
element. If the load current waveform is rectangular, it will
result in an SSR release error.
When switching ON and OFF a load whose waves are all
rectified, use Power MOS FET Relay.
-V-model SSRs: G3F-203SL-V, G3H-203SL-V
Power MOS FET Relay: G3DZ, G3RZ, G3FM
Note. Refer to "Control Component Catalogue" (Catalogue number:
SAOO-206) for detailed specification of G3FM models.
7. Small-capacity Loads
Even when there is no input signal to the SSR, there is a small
leakage current (IL) from the SSR output (LOAD). If this
leakage current is larger than the load release current, the
SSR may fail to release. Connect a bleeder resistance R in
parallel to increase the SSR switching current.
R<
E
IL−I
E: Load (e.g., relays) release voltage
I: Load (e.g., relays) release current
Bleeder resistance R
Load
Load power supply
Inrush current (A. Peak)
2. Lamp Load
A large inrush current flows through incandescent lamps,
halogen lamps, and similar devices (approx. 10 to 15 times
higher than the rated current). Select an SSR so that the peak
value of inrush current does not exceed half the inrush current
resistance of the SSR. Refer to “Repetitive” (indicated by the
dashed line) shown in the following figure. When a repetitive
inrush current of greater than half the inrush current resistance
is applied, the output element of the SSR may be damaged.
Bleeder resistance standards: 100-VAC power supply, 5 to 10 kΩ, 3 W
200-VAC power supply, 5 to 10 kΩ, 15 W
C-343
Solid State Relays Common Precautions
1. Heater Load (Resistive Load)
A resistive load has no inrush current. The SSR is generally
used together with a pulse-voltage-output in temperature
controller for heater ON/OFF switching. When using an SSR
with the zero cross function, most generated noise is
suppressed. This type of load does not, however, include
all-metal and ceramic heaters. Since the resistance values at
normal temperatures of all-metal and ceramic heaters are low,
an overcurrent will occur in the SSR, causing damage. For
switching of all-metal and ceramic heaters, select a Power
Controller (G3PW, consult your OMRON representative) with
a long soft-start time, or a constant-current switch.
Solid State Relays Common Precautions
8. Inverter Load
Do not use an inverter-controlled power supply as the load
power supply for the SSR. Inverter-controlled waveforms
become rectangular, so the dV/dt ratio is extremely large and
the SSR may fail to release.
An inverter-controlled power supply may be used on the input
side provided the effective voltage is within the normal
operating voltage range of the SSR.
Trigger voltage
0
Trigger voltage
A
B
A and B: Loss time
ΔV/ΔT = dV/dt: voltage increase ratio
The dV/dt ratio tends to infinity,
so the SSR will not turn OFF.
Voltage waveform
Solid State Relays Common Precautions
9. Capacitive Load
The supply voltage plus the charge voltage of the capacitor is
applied to both ends of the SSR when it is OFF. Therefore,
use an SSR model with an input voltage rating twice the size
of the supply voltage. Limit the charge current of the capacitor
to less than half the peak inrush current value allowed for the
SSR.
10. SSR for DC Switching
Connection
With the SSR for DC switching, the load can be connected to
either negative (-) or positive (+) output terminal of the SSR.
Protective Component
Since the SSR does not incorporate an overvoltage absorption
component, be sure to connect an overvoltage absorption
component when using the SSR under an inductive load.
■Load Power Supply
1. Rectified Currents
If a DC load power supply is used for full-wave or half-wave
rectified AC currents, make sure that the peak load current does
not exceed the maximum usage load power supply of the SSR.
Otherwise, overvoltage will cause damage to the output element
of the SSR.
Peak voltage
SSR operating
voltage maximum
value
2. Operating Frequency for AC Load Power Supply
The operating frequency range for an AC load power supply is
47 to 63 Hz.
3. Low AC Voltage Loads
If the load power supply is used under a voltage below the
minimum operating load voltage of the SSR, the loss time of the
voltage applied to the load will become longer than that of the
SSR operating voltage range. See the following load example.
(The loss time is A < B.)
Before operating the SSR, make sure that this loss time will not
cause problems.
If the load voltage falls below the trigger voltage, the SSR will not
turn ON, so be sure to set the load voltage to 75 VAC min.
Current waveform
An inductance (L) load
causes a current phase delay
as shown on the left.
Therefore, the loss is not as
great as that caused by a
resistive (R) load.
This is because a high
voltage is already imposed on
the SSR when the input
current to the SSR drops to
zero and the SSR is turned
OFF.
4. Phase-controlled AC Power Supplies
Phase-controlled power supply cannot be used.
■Operating and Storage Environments
1. Operating Ambient Temperature
The rated value for the ambient operating temperature of the
SSR is for when there is no heat build-up. For this reason, under
conditions where heat dissipation is not good due to poor
ventilation, and where heat may build up easily, the actual
temperature of the SSR may exceed the rated value resulting in
malfunction or burning.
When using the SSR, design the system to allow heat dissipation
sufficient to stay below the “●Load Current vs. Ambient
Temperature” characteristic curve. Note also that the ambient
temperature of the SSR may increase as a result of
environmental conditions (e.g., climate or air-conditioning) and
operating conditions (e.g., mounting in an airtight panel).
2. Transportation
When transporting the SSR, observe the following points. Not
doing so may result in damage, multifunction, or deterioration of
performance characteristics.
3. Vibration and Shock
Do not subject the SSR to excessive vibration or shock.
Otherwise the SSR may malfunction and internal components
may be damaged.
To prevent the SSR from abnormal vibration, do not install the
SSR in locations or by means that will subject it to vibration from
other devices, such as motors.
4. Solvents
Do not allow the SSR to come in contact with solvents, such as
thinners or gasoline. Doing so will dissolve the markings on the
SSR.
5. Oil
Do not allow the SSR terminal cover to come in contact with oil.
Doing so will cause the cover to crack and become cloudy.
C-344
Solid State Relays Common Precautions
■Actual Operation
■Safety Concept
1. Leakage Current
1. Error Mode
A leakage current flows through a snubber circuit in the SSR
even when there is no input. Therefore, always turn OFF the
input or load and check that it is safe before replacing or wiring
the SSR.
The SSR is an optimum relay for high-frequency switching and
highspeed switching, but misuse or mishandling of the SSR may
damage the elements and cause other problems. The SSR
consists of semiconductor elements, and will break down if these
elements are damaged by surge voltage or overcurrent. Most
faults associated with the elements are short-circuit
malfunctions, whereby the load cannot be turned OFF.
Therefore, to provide a safety feature for a control circuit using
an SSR, design a circuit in which a contactor or circuit breaker
on the load power supply side will turn OFF the load when the
SSR causes an error. Do not design a circuit that turns OFF the
load power supply only with the SSR. For example, if the SSR
causes a half-wave error in a circuit in which an AC motor is
connected as a load, DC energizing may cause overcurrent to
flow through the motor, thus burning the motor. To prevent this
from occurring, design a circuit in which a circuit breaker stops
overcurrent to the motor.
Exercise care when pulling or inserting the hold-down clips so
that their form is not distorted. Do not use a clip that has already
been deformed. Otherwise excessive force will be applied to the
SSR, causing it not to perform to its specification, and also it will
not have enough holding power, causing the SSR to be loose,
and resulting in damage to the contacts.
5. PCB SSR Soldering
 SSRs must be soldered at 260°C within five seconds. For
models, however, that conform to separate conditions,
perform soldering according to the specified requirements.
 Use a rosin-based non-corrosive flux that is compatible with
the material of the SSR.
6. Ultrasonic Cleaning
Do not perform ultrasonic cleaning. Performing ultrasonic
cleaning after the SSR base has been installed will cause
ultrasonic waves to resonate throughout the SSR internal
structure, thereby damaging the internal components.
Cause
Result
Overvoltage
Input element damage
Overvoltage
Output area
Output element damage
Overcurrent
Ambient temperature
exceeding maximum
Whole Unit
Output element damage
Poor heat radiation
2. Short-circuit Protection
A short-circuit current or an overcurrent flowing through the load
of the SSR will damage the output element of the SSR. Connect
a quick-break fuse in series with the load as a short-circuit
protection measure.
Design a circuit so that the protection coordination conditions for
the quick-break fuse satisfy the relationship between the SSR
surge resistance (IS), quick-break fuse current-limiting feature
(IF), and the load inrush current (IL), shown in the following chart.
IS>IF>IL
IS
IF
IL
Time (ms)
3. Operation Indicator
The operation indicator turns ON when current flows through the
input circuit. It does not indicate that the output element is ON.
C-345
Solid State Relays Common Precautions
4. Hold-down Clips
Location
Input area
Output terminal
Do not attempt to repair or use a terminal that has been
deformed. Otherwise excessive force will be applied to the SSR,
and it will lose its original performance capabilities.
Output circuit
3. Deformed Terminals
Input indicator
Do not cut the terminals using an automated-cutter. Cutting the
terminals with devices such as an automated-cutter may
damage the internal components.
Input circuit
2. Cutting Terminals
Peak current (A)
Leakage
current
Input terminal
Snubber circuit
Varistor
Trigger circuit
Input circuit
Switch element
Solid State Relays Common Precautions
■HANDLING THE SSR
■PCB-mounting SSRs
●Do Not Drop
1. Suitable PCBs
The SSR is a high-precision component. Do not drop the SSR or
subject it to excessive vibration or shock regardless of whether
the SSR is mounted or not.
The maximum vibration and shock that an SSR can withstand
varies with the model. Refer to the relevant datasheet.
The SSR cannot maintain its full performance capability if the
SSR is dropped or subjected to excessive vibration or shock.
In addition, it may result in malfunction due to its damaged
internal components if the SSR is dropped or subjected to
excessive vibration or shock.
The impact of shock given to the SSR that is dropped varies
upon the case. For example, if a single SSR is dropped on a
plastic tile from a height of 10 cm, the SSR may receive a shock
of 1,000 m/s2 or more. (It depends on the floor material, the
angle of collision with the floor, and the dropping height.)
Handle the SSR models in stick packages with the same care
and keep them free from excessive vibration or shock.
●Terminal arrangement/Internal connections
Solid State Relays Common Precautions
1. BOTTOM VIEW
If the relay's terminals cannot be seen from above, as in this
example, a BOTTOM VIEW is shown.
2. Rotating direction to BOTTOM VIEW
The following shows the terminal rotated in the direction
indicated by the arrow, with the coil always on the left
(orientation mark on the left).
Axis of rotation
1 PCB Material
PCBs are classified into epoxy PCBs and phenol PCBs. The
following table lists the characteristics of these PCBs. Select
one, taking into account the application and cost. Epoxy PCBs
are recommended for SSR mounting in order to prevent the
solder from cracking.
Material
Epoxy
Phenol
Paper phenol
Item
(PP)
 New PCBs are
highly insulationresistive but easily
 High insulation
 Inferior to glass
affected by moisture
resistance.
epoxy but
Electrical
absorption and
superior to paper
characteristics  Highly resistive to
cannot maintain
phenol PCBs.
moisture absorption.
good insulation
performance over a
long time.
 The dimensions are
 The dimensions are
not easily affected by  Inferior to glass
easily affected by
temperature or
temperature or
epoxy but
Mechanical
humidity.
humidity.
superior to paper
characteristics
phenol PCBs.
 Ideal for through-hole
 Not suitable for
or multi-layer PCBs.
through-hole PCBs.
Economical
 Expensive
 Rather expensive  Inexpensive
efficiency
 Applications that
may require less
reliability than
 Applications in
those for glass
 Applications that
comparatively good
epoxy PCBs but
require high
Application
environments with
require more
reliability.
low-density wiring.
reliability than
Glass epoxy
(GE)
Paper epoxy
(PE)
those of paper
phenol PCBs.
2 PCB Thickness
The PCB may warp due to the size, mounting method, or
ambient operating temperature of the PCB or the weight of
components mounted to the PCB. Should warping occur, the
internal mechanism of the SSR on the PCB will be deformed
and the SSR may not provide its full capability. Determine the
thickness of the PCB by taking the material of the PCB into
consideration.
3 Terminal Hole and Land Diameters
Refer to the following table to select the terminal hole and land
diameters based on the SSR mounting dimensions. The land
diameter may be smaller if the land is processed with through-hole
plating.
Hole dia. (mm)
Nominal value Tolerance
0.6
0.8
1.0
1.2
±0.1
1.3
1.5
1.6
2.0
Minimum land dia. (mm)
1.5
1.8
2.0
2.5
2.5
3.0
3.0
3.0
2. Mounting Space
The ambient temperature around the sections where the SSR is
mounted must be within the permissible ambient operating
temperature. If two or more SSRs are mounted closely together,
the SSRs may radiate excessive heat. Therefore, make sure that
the SSRs are separated from one another at the specified
distance provided in the datasheet. If there is no such
specification, maintain a space that is as wide as a single SSR.
Provide adequate ventilation to the SSRs as shown in the
following diagram.
Top
Ventilation airflow
Bottom
Top
Bottom
Ventilation airflow
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Solid State Relays Common Precautions
3. Mounting SSR to PCB
Read the precautions for each model and fully
familiarize yourself with the following information
when mounting the SSR to the PCB.
Step 1
SSR mounting
Step 2
Flux coating
Flux
1. Do not bend the terminals to make the SSR
self-standing, otherwise the full
performance of the SSR may not be
possible.
2. Process the PCB properly according to the
mounting dimensions.
1. The flux must be a non-corrosive rosin flux,
which is suitable to the material of the SSR.
Apply alcohol solvent to dissolve the flux.
2. Make sure that all parts of the SSR other
than the terminals are free of the flux. The
insulation resistance of the SSR may be
degraded if there is flux on the bottom of
the SSR.
Step 5
Cooling
Step 6
Cleaning
1. After soldering the SSR, be sure to cool
down the SSR so that the soldering heat
will not deteriorate the SSR or any other
components.
2. Do not dip the SSR into cold liquid, such as
a detergent, immediately after soldering the
SSR.
1. Refer to the following table for the selection
of the cleaning method and detergent.
Detergent
Boiling or dip cleaning is possible for the SSR. Do
not perform ultrasonic cleaning or cut the
terminals, otherwise the internal parts of the SSR
may be damaged. Make sure that the temperature
of the detergent is within the permissible ambient
operating temperature of the SSR.
2. Applicability of Detergents
Preheating
Heater
1. Be sure to preheat the SSR to allow better
soldering.
2. Preheat the SSR under the following
conditions.
Step 4
OK
OK
Temperature
100°C max.
 Indusco  Holys
Aqueous
 Pure water (pure hot
detergent
water)
Time
1 min max.
Alcohol
 IPA  Ethanol
OK
Others
 Paint thinner
 Gasoline
NG
3. Do not use the SSR if it is left at high
temperature over a long time. This may
change the characteristics of the SSR.
Soldering
Applicability
 Perochine
Chlorine
Chlorosolder
detergent
 Trichloroethylene
Note 1. Contact your OMRON representatives
before using any other detergent. Do not
apply Freon TMC, paint thinner, or gasoline
to any SSR.
Note 2. The space between the SSR and PCB may
be not be adequately cleaned with a
hydrocarbon or alcohol detergent.
●Automatic Soldering
1. Flow soldering is recommended for
maintaining a uniform soldering quality.
 Solder: JIS Z3282 or H63A
 Soldering temperature: Approx. 250°C
(Approx. 260°C for DWS)
 Soldering time: Approx. 5 s
(Approx. 2 s for first time and approx. 3 s
for second time for DWS)
 Perform solder level adjustments so that
the solder will not overflow on the PCB.
●Manual Soldering
1. After smoothing the tip of the soldering
iron, solder the SSR under the following
conditions.
 Solder: JIS Z3282,
1160A, or H63A with
rosin-flux-cored solder
Solder
Flux
 Soldering iron: 30 to 80 W
 Soldering temperature:
280°C to 350°C
 Soldering time: Approx. 3 s
2. As shown in the above illustration, solder
with a groove for preventing flux dispersion.
Actions are being taken worldwide to stop
the use of CFC-113 (chlorofluorocarbon)
and 1.1.1 trichloroethane. Your
understanding and cooperation are highly
appreciated.
Step 7
Coating
1. Do not fix the whole SSR with resin,
otherwise the characteristics of the SSR
may change.
2. The temperature of the coating material
must be within the permissible ambient
operating temperature range.
Coating
Type
Applicability
Epoxy
OK
Urethane
OK
Silicone
OK
Note. When soldering PCB SSR with high-heat
capacity such as the G3M, make sure that
the soldering of SSR terminals is properly
performed.
C-347
Solid State Relays Common Precautions
Detergent
Step 3
Solid State Relays Common Precautions
■Application Circuit Examples
1. Connection to Sensors
(Brown)
Sensor
Load power supply
The SSR connects directly to a Proximity Sensor or
Photoelectric Sensor.
Load
(Black)
(Blue)
Sensors:
TL-X Proximity Sensor
E3S Photoelectric Sensor
Load power supply
2. Switching Control of Incandescent Lamps
Incandescent
lamp
Input signal
source
Load power supply
3. Temperature Control of Electric Furnaces
Load
heater
Input signal
source and
Temperature
Controller
4. Forward and Reverse Operation of Singlephase
Inductive Motors
Motor
Load power supply
Solid State Relays Common Precautions
*
Note 1. The voltage between the load terminals of either SSR 1 or SSR
2 when turned OFF is approximately twice as high as the supply
voltage due to LC coupling. Be sure to use an SSR model with
a rated output voltage of at least twice the supply voltage.
For example, if the motor operates at a supply voltage of 100
VAC, the SSR must have an output voltage of 200 VAC or
higher.
Note 2. Make sure that there is a time lag of 30 ms or more to switch
over SW1 and SW2.
* Resistor to limit advanced phase capacitor discharge current.
To select a suitable resistor, consult with the manufacturer of the
motor.
C-348