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DC Electronic Circuit Protector (24 VDC 4 Outputs/8 Outputs Type)


Simplified safety design of DC circuits Reliable DC circuit protection in the event of short circuits or overcurrent Saves space even with multi-channels Sequential start-up of outputs to avoid start-up trouble

Ratings, Characteristics, and Functions

Model S8V-CP0424 S8V-CP0424S S8V-CP0824
Number of Outputs 4 4 8
UL Class 2 output No Yes No
Rated input voltage
(Input voltage allowable range)
24 VDC
(20 to 30 VDC)
24 VDC
(20 to 28.8 VDC)
24 VDC
(20 to 30 VDC)
Allowable input current *1 40 A 15.2 A 70 A
Max. rated output current (per
10 A 3.8 A 10 A
Internal voltage drop *2 180 mV typ. 180 mV typ. 200 mV typ.
Output leakage current 10 mA max.
(at input
24 VDC) *3
When all outputs
are connected
8 W typ.
(at 10 A x 4 CH)
4 W typ.
(at 3.8 A x 4 CH)
15 W typ.
(at 10 A x 7 CH)
When all outputs
are tripped
0.7 W typ. 0.8 W typ. 1.1 W typ.
time *4
Initialization time 250 ms typ.
Start-up delay
50 ms to 5 s
Functions *5 Current
function *6
Rated output
2 A, 3 A, 4 A, 6 A,
8 A, 10 A
3.8 A 2 A, 3 A, 4 A, 6 A,
8 A, 10 A
Cutoff current 2.5 A, 3.5 A, 4.5 A,
6.5 A, 8.5 A, 10.5 A
3.8 A 2.5 A, 3.5 A, 4.5 A,
6.5 A, 8.5 A, 10.5 A
Over voltage tripping function *6 No Yes No
Push button (ON/OFF/RESET)
with indicator
Yes (LED colors: Red/Green/Yellow)
Reset signal input (RST) Yes (High level: 20 to 30 VDC, Low level: 0 to 5 VDC)
Alarm signal output (ALM1/
Yes (MOS FET relay output 30 VDC max., 50 mA max.)
Insulation Dielectric strength 1.0 kVAC for 1 min (between all terminals and DIN rail
mounting parts), current cutoff 20 mA
Insulation resistance 100 MΩ min. (between all terminals and DIN rail mounting
parts) at 500 VDC
Environment Ambient operating temperature -25 to 70°C (Derating is required according to the temperature.)
(with no condensation or icing)
Storage temperature -40 to 85°C (with no condensation or icing)
Ambient operating humidity 5% to 96% (storage humidity: 5% to 96%)
Vibration resistance 10 to 55 Hz, maximum 5 G, 0.42 mm half amplitude for 2 h
each in X, Y, and Z directions
Shock resistance 294 m/s2, 3 times each in ±X, ±Y, ±Z directions
Reliability MTBF *7 135,000 hrs typ. 60,000 hrs typ. 60,000 hrs typ.
Life expectancy *8 10 years min.
Construction Weight 160 g max. 170 g max. 420 g max.
Cooling fan No
Degree of protection IP20 by IEC60529
Standards EMI Conforms to EN 61000-6-3
EMS Conforms to EN 61000-6-2
Safety standards UL 508 (CSA22.2 No.14-10) Listing Pol2
UL 2367 Recognition (Max. 100W per output, per Class 2
limitations) Pol2 *9
CE (EN 61000-6-2, EN 61000-6-3)
EAC (TR CU 020 / 2011)

*1. For power input terminals, use 35 A max. per pole.
*2. A voltage drop will occur in the S8V-CP. Consider the voltage drop at the output.
*3. When selecting the power supply, be sure to include the power consumption of the S8V-CP and not just the power consumption of the load.
*4. Outputs start in order from +VO1 to +VO8. +VO1 starts after the initialization time. Start-up delay time of each output is automatically decided depending on the load. If the start-up delay time is over 5 s, the next output is forcibly started.
*5. Refer to Tripping Functions for details.
*6. Refer to Current Tripping Characteristics and Current and Voltage Tripping Characteristics for details.
*7. MTBF is calculated according to JEITA RCR-9102.
*8. Refer to Recommended Replacement Periods and Periodic Replacement for Preventive Maintenance on Catalog for details.
*9. UL Class 2 output applies for the S8V-CP0424S model only.

Tripping Functions

Current tripping

If the output current of each output exceeds the current tripping, the output is tripped by a semiconductor switch (MOS FET) in accordance with the current tripping characteristic.

Over voltage tripping

With the S8V-CP0424S, if the input voltage exceeds 28.8 V, all outputs are tripped by a semiconductor switch (MOS FET).
If the input voltage becomes 28.8 V or less, all outputs automatically return to the previous state.

Reset Signal Input (RST)

Turning ON all outputs during in the Current tripping (enable to reset) state is called reset. Output terminals in the Current tripping (enable to reset) state can be reset by an external input. As shown in the following figure, input a high level signal of 0.5 s or more and reset.
 Input voltage: 30 VDC max.
 Input impedance: 22 kΩ

S8V-CP Specifications 6

Note: 1. When Reset signal input terminal is used, a miss operation of reset may occur by a noise coming from the cable. Do not make an instable potential of Reset signal input terminal.

Alarm Signal Output (ALM1/ALM2)

If any of the output is tripped, the MOS FET relay is turned OFF. The signal output comprises of MOS FET relays and therefore, does not have polarity.
 Input voltage: 30 VDC max., Input current: 50 mA max.
 Residual voltage when ON: 2 V max.
 Leakage current when OFF: 0.1 mA max.
1. Alarm signal output is not equipped with an internal current limiting circuit, so be sure that the current flowing to the alarm signal output terminals does not exceed 50 mA.
2. Be sure to check that the Alarm signal outputs are working normally after wiring.

Output Status

The status of each output can be identified by the indicator or alarm signal output.
The status of each output is saved when the power is turned OFF. When the power is turned ON again, the status transits to that saved after initialization.
All outputs are set to Output ON state by default.

Indicator Alarm
Output Status Name Status Transition
by Push Button
Status Transition
by Reset Signal Input
Color Status
--- OFF OFF OFF Initialization --- ---
Green ON ON ON Output ON Manually output OFF ---
Yellow ON ON ON Over current *1 Manually output OFF ---
Red ON OFF OFF Manually output OFF Output ON ---
Red Blinking OFF OFF Current tripping
(Disable to reset) *2
--- ---
Yellow Blinking OFF OFF Current tripping
(Enable to reset)
Manually output OFF Output ON
(transition due to positive
pulse longer than 0.5 s)
Red Blinking
OFF OFF Over voltage tripping *3
Internal error detection *4
--- ---

*1. Each output transits automatically to Current tripping (disable to reset) state according to the Current tripping characteristics.
*2. The status remains on Current tripping (disable to reset) state during 500 ms to 20 s in order to protect the internal parts from heat.
  After that, the status automatically transits to Current tripping (enable to reset) state.
*3. S8V-CP0424S only
*4. If an internal fuse blows, or an internal memory error occurs, the output will be disconnected.
*5. Always remove the cause of the output first and then reset the alarm when abnormal tripping operates.

Engineering Data

Derating Curves


S8V-CP Specifications 14


S8V-CP Specifications 15


S8V-CP Specifications 16

Current Tripping Characteristics

S8V-CP0424, S8V-CP0824

S8V-CP Specifications 18

Note: If the power rating of the power supply unit is insufficient, the overcurrent protection characteristic can cause a voltage drop in all the outputs.
In order to trip the current according to the above characteristic, select a power supply unit with a current higher than the total tripping current considering the power consumption of the S8V-CP.

Current and Voltage Tripping Characteristics


S8V-CP Specifications 20

Note: 1. Input voltage 24 to 28.8 VDC tripping current is decreased to less than 3.2 A in accordance with the current and voltage tripping characteristic.
   2. Current tripping takes place between 250 ms to 5 s.