MP240D4 OPTO 22, MP240D4 Datasheet - Page 18

• Manufacturer Part Number: MP240D4
• Description: Solid State Relay
• Manufacturer: OPTO 22

Specifications of MP240D4

• Control Voltage Type: DC
• Input Voltage: 3VDC To 24VDC
• Load Current: 4A
• Load Voltage Range: 24VAC To 280VAC
• Switching Mode: Zero Cross
• Relay Terminals: Through Hole
• Load Voltage Max: 280VAC
• Load Voltage Min: 24VAC
• Capacitance: 8 pF (Max.) Coupling (Input-Output)
• Current, Surge, Non-repetitive Peak: 85 Apeak @ 1 Cycle
• Dimensions: 1.70 in. L x 0.40 in. W x 0.98 in. D
• Control Voltage Max: 32V
• Control Voltage Min: 3V
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DATA SHEET
FAQ: SSR Applications (cont.)
Q : What does a “zero-crossing” turn-on circuit refer
to?
A :“Zero-crossing” turn-on and turn-off refer to the point on the AC
wave form when the voltage is zero. It is at this point that an AC
SSR will turn on or off. All Opto 22 AC relays are designed with a
zero-crossing turn-on and turn-off circuit. When the AC circuit volt-
age is at zero, no current is flowing. This makes it much easier and
safer for the semiconductor device in the relay to be turned on or off.
It also generates much less electrical EMI/RFI noise.
Q : Can I use an AC SSR to switch DC?
A : No. Because of the zero crossing circuit described above, the
relay will most likely never turn on, and even if it is on, it will likely
not be able to be turned off, as DC voltage typically never drops to
zero.
Q : Can I use a DC SSR to switch AC?
A : No. The semiconductor device used in Opto 22’ s DC SSRs is
polarized. It may break down and conduct for the portion of the
waveform that is reversed in polarity.
Q : Can a DC SSR be used to switch an analog signal?
A : This is not recommended at all, for several reasons. First, the
voltage drop across the relay will cause signal loss. Second, the con-
duction characteristics of the SSR are very non-linear at low operat-
ing voltages and currents. Use a mechanical relay; it will work much
better.
Q : What agency approvals do your SSRs carry?
A : In general, Opto 22 relays carry UL, CSA, and CE approval. See
http://www.opto22.com/support/agency.aspx.
Additionally, some SSRs contain VDE-approved optocouplers;
contact Opto 22 for more information.
Form 859-050513
Dimension and specifications are subject to change. All products and/or company names throughout this data sheet are generally trademarks or registered trademarks of their respective companies.
Opto 22 • 43044 Business Park Drive • Temecula, CA 92590 • Phone: [phone] • 800-321-OPTO • Fax: [phone] • www.opto22.com
Inside Sales: 800-321-OPTO • E-mail: [e-mail] • Product Support: 800-TEK-OPTO • 951-695-3080 • Fax: [phone]
FAQ: SSR Troubleshooting
Q : My SSR does not function anymore. What may have
happened?
A : There is no “normal” mode of failure for SSRs. Most of the time,
they just stop working, by refusing to turn on or off. Often, an
improper installation is to blame for an SSR failure, as these are
very simple, reliable devices. If you have a failed SSR, it is important
to look at the normal operating parameters of that relay within the
larger system to make sure that the relay being used is appropriate
to the application, and that the relay is being properly installed in the
system. The three most common causes of SSR failure are as fol-
lows:
destroyed by overheating from carrying too much current
too long.
tor is less tough than a simple metal contact. Reverse voltages
exceeding the PRV rating of the relay will cause damage. Voltage
spikes on the switched line, perhaps from inductive kickback,
destroyed one or more of the internal switching devices. Remember
to use snubbers, transorbs, MOVs, and/or commutating diodes on
highly inductive loads.
large enough heat sink, or no thermal compound was used, causing
the relay to overheat. Also, insufficient tightening of the load termi-
nals can cause arcing and ohmic heating of the relay. Opto 22 rec-
ommends 15 to 16 inch-pounds of torque on the load screw
terminals. Similar failures have also been attributed to the use of
crimp-on terminal lugs or spades; make sure such terminals are
tightly crimped, and even drip some solder into the joint to ensure
good electrical contact and protection from corrosion.
SOLID-STATE RELAYS
1) SSR improperly matched to load. The relay was
2) SSR insufficiently protected. Remember, a semiconduc-
3) SSR improperly installed. The SSR was not mounted to a
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