Omron S8M-CP04, S8M-CP04-R, S8M-CP04-RS Product Manual

Digital Multicircuit Protector S8M 1

Digital Multicircuit Protector

S8M

Complete Flexible DC Circuit Protector That
Has a Wide Array of Displays, Alarm
Outputs, and Other Digital Functions.

• Four circuit protectors in one package

• Simple setting of curr ent tripping values for each bra nch outputs
in 0.1-A units

• Startup and shutdown sequence control

• Display and alarm functions (Input voltage, output current,
run time, and over-temperature)

• Outputs conform to UL Class 2 (at 24 VDC, S8M-CP04-RS
only)

• DIN Rail mounting

• Free Support Tool available

Note: Refer to Precautions for Safe Use on page 20.

Model Number Structure

■Model Number Lege nd

Note: Not all combinations are possible. Please refer to the list of models in Ordering Information below.

1. Communications

None: Not supported
R: Supported (RS-232)

2. UL Class 2 Output (at 24 VDC)

None: Not compliant
S: Compliant

Ordering Information

Note: For details on normal stock models, contact your nearest

OMRON representative.

Recommended Power Supplies

Note: When selecting the power supply , be sure to include the

internal power consumption of the S8M (approx. 10 W) and not
just the power consumption of the load.

12

S8M-CP04- @@

Communications UL Class 2 output Model number

None Not compliant S8M-CP04
Supported (RS-232C) Not compliant S8M-CP04-R

Compliant S8M-CP04-RS

Series name Model number

S8VS S8VS-06024@@

S8VS-09024@@
S8VS-12024@@
S8VS-18024@@
S8VS-24024@@

S8VM S8VM-05024@@

S8VM-10024@@
S8VM-15024@@
S8VM-30024C
S8VM-60024C

This Datasheet describes only the minimum setting operations required when using the S8M for the first time.
Refer to the S8M User's Manual (Cat. No. Z241), when making further settings.

2 Digital Multicircuit Protector S8M

Specifications

■Ratings/Characteristics

Item Model S8M-CP04 S8M-CP04-R S8M-CP04-RS
Number of branches 4
I/O

character­istics

Rated input voltage 24 VDC (19.2 to 26.4 VDC)
Allowable input current 17.0 A max. 16.0 A max.
Maximum tripping output current

(per branch output)

4.0 A 3.8 A

Internal voltage drop (See note 1.) 0.5 VDC max. (at 4.0 A) 0.7 VDC max. (at 3.8 A)
Output leakage current 10 mA max.
Power

consump­tion
(See note 2.)

4 branches output,
normal operation

10 W max. (at 4.0 A) 15 W max. (at 3.8 A)

4 branches output,
tripping operati on

3 W max.

Functions Tripping Abnormal voltage

tripping

28.8 V (fixed), tripping alarm output

Abnormal current
tripping

Setting range: 0.5 to 4.0 A (in 0.1-A units), tripping alarm
output

Setting range: 0.5 to 3.8 A (in 0.1-A
units), tripping alarm output

Tripping alarm out­put

Transistor output
30 VDC max., 50 mA max., leakage current: 0.1 mA max., residual voltage: 2 V max.

Alarms Ove rvoltage Setting range: 20.0 to 28.8 V (in 0.1-V units), alarm output

Undervoltage Setting range: 18.0 to 26.4 V (in 0.1-V units), alarm output
Overcurrent Setting range: 0.5 to 4.0 A (in 0.1-A units), alarm output Setting range: 0.5 to 3.8 A (in 0.1-A

units), alarm output

Run time Setting range: 0.0 to 99.9 kh (in 0.1-kh units), alarm output

(The alarm output is disabled if the time is set to 0.0 kh.)

Alarm output Transistor output

30 VDC max., 50 mA max., leakage current: 0.1 mA max., residual voltage: 2 V max.

Temperature Temperature Setting range: 25 to 80

°C, over-temperature output

Over-temperature
output

Transistor output
30 VDC max., 50 mA max., leakage current: 0.1 mA max., residual voltage: 2 V max.

Display Input voltage Display range: 17.0 to 30.0 V

Display accuracy: 2% rdg

±1 digit max.

Output current Branch output display range: 0.0 to 4.0 A

Peak output current display range:0.0 to 10.0 A
Total current display range: 0.0 to 40.0 A
Display accuracy: 5% FS (4 A)

±1 digit max.

Run time Display range: 0.0 to 99.9 kh

Display accuracy: 2% rdg

±1 digit max.

Temperature Display range:

−10 to 100°C

Display accuracy: 2

°C ±1 digit max.

External tripping input 19.2 to 30 VDC, minimum signal width: 10 ms, tripping within 20 ms of input
Startup sequence Can be enabled/disabled for each branch output, setting range: 0.0 to 99.9 s in 0.1-s units.
Shutdown sequence Can be enabled/disabled for each branch output, setting range: 0.0 to 99.9 s in 0.1-s units.
Communications None Supported (RS-232C)
Sampling pe r i od 1 ms

Digital Multicircuit Protector S8M 3

Note: 1. A voltage drop will occur in the S8M. Consider the voltage drop at the output.

2. When selecting the power supply, be sure to include the internal power consumption of the S8M (approx. 10 W) and not just the power

consumption of the load.

3. Refer to Engineering Data on page 6 for details.

Other Ambient operating temperature Refer to the derating curve in Engineering Data (with no condensation or icing) (See note 3.)

Storage temperature

−25 to 65°C

Ambient operating humidity 25% to 85% (storage humidity: 25% to 90%)
Dielectric strength 1.0 kVAC for 1 min (between all charged sections and all non-charged sections; detection cur-

rent: 20 mA)
500 VAC for 1 min (between all I/O and I/O signals/communications; detection current: 20 mA)
500 VAC for 1 min (between all I/O signals and communications; detection current: 20 mA)
500 VAC for 1 min (between input signals and all output signals; detection current: 20 mA)

Insulation resistance 100 M

Ω min. (between all charged sections and all non-charged sections) at 500 VDC

100 M

Ω min. (between all I/O and I/O signals/communications) at 500 VDC

100 M

Ω min. (between all I/O signals and communications) at 500 VDC

100 M

Ω min. (between input signals and all output signals) at 500 VDC

Vibration resistance 10 to 55 Hz, 0.375-mm single amplitude for 2 h each in X, Y, and Z directions
Shock resistance

150 m/s

2

, 3 times each in ±X, ±Y, and ±Z directions

EMI Conducted

Emission

Conforms to EN 61204-3 Class B

Radiated Emission Conforms to EN 61204-3 Class B
EMS Conforms to EN 61204-3 High severity levels
Approved standards UL: UL 508 (Listing), UL 60950-1

cUL: CSA C22.2 No. 107.1
cUR: CSA No. 60950-1
EN/VDE:EN 50178 (= VDE 0160), EN 60950-1

(= VDE 0805 Teil 1)

UL: UL 508 (Listing, Class 2:

Per UL 1310), UL60950-1
cUL: CSA C22.2 No. 107.1
cUR: CSA No. 60950-1
EN/VDE:EN 50178

(= VDE 0160),

EN 60950-1

(= VDE 0805 Teil 1)

Weight 400 g max.

Item Model S8M-CP04 S8M-CP04-R S8M-CP04-RS

4 Digital Multicircuit Protector S8M

Connections

■Block Diagrams

DC branch output 4

−V

+V

DC branch output 3

−V

+V

DC branch output 2

Fuse

Cutoff
circuit

Current-detection

resistor

Cutoff
circuit

Cutoff
circuit

Voltage

detection

S8M-CP04-R/-RS only

Power supply

circuit

Communications

circuit

Communi­cations
terminals
RS-232C

Display

circuit

Switch

Processing

circuit

Temperature

detection

Current-detection

resistor

Current-detection

resistor

Cutoff
circuit

Thermal

fuse

Thermal

fuse

Current-detection

resistor

Cutoff
circuit

Current-detection

resistor

Cutoff
circuit

Thermal

fuse

Current-

limiting

circuit

Current-

limiting

circuit

Current-

limiting

circuit

Current-

limiting

circuit

Current-detection

resistor

Cutoff
circuit

Current-detection

resistor

Cutoff
circuit

Thermal

fuse

Fuse

Fuse

Fuse

−V

+V

DC branch output 1

−V

+V

+V

−V

Tripping alarm
output

Alarm output

Over­temperature
output

External
tripping input

DC input
power supply

SD
RD
SG

S8M-CP04-RS only

Current-detection

resistor

Digital Multicircuit Protector S8M 5

Construction and Nomenclature

■Nomenclature

Note: 1. For detailed display methods, refer to Status Indicators on

page 13.

2. Configured from independent circuits, and either sinking or
sourcing applications are possible.

3. Indicators 1 to 4 will not light except when the current is
being displayed.

4. Press for at least 3 s to enable operation.

5. Except for the S8M-CP04.

4 5 6 7

1

14

10
11

3

8

9
13
12

2

4 Tripping alarm output (TRP)

5 Alarm output (ALM)

6 Over-temperature output (TMP)

7 External tripping input (TRG)

Internal circuit configuration

Note: The S8M-CP04-RS is shown above.

No. Name Function

1 Power Input Terminals

(+V), (

−V)

Connect to the input line.

2 Branch Output

Terminals (+V), (

−V)

Connect to the load lines.
Up to four branch outputs can be
connected.

3 Status Indicators

(Red, Green)

Indicate the connection and cutoff
status for each branch output.
Cut off: Red, Connected: Green (See
note 1.)

4 Tripping Alarm Output

(+,

−)

Output (transistor: OFF) when the
error tripping operation functions.
(See note 2.)

5 Alarm Output (+,

−) Output (transistor: OFF) when a set

value for alarm detection is exceeded.
(See note 2.)

6 Over-temperature

Output (+,

−)

Output (transistor: OFF) when a set
value for over-temperature detection
is exceeded. (See note 2.)

7 External Tripping Input

(+,

−)

The tripping operation can be
executed with an externally input
signal.

8 Seven-segment Display

(Red)

Displays measured values and set
values.

9 Unit Indicators

(Orange)

V Lit when the input voltage is being

displayed.

A Lit when the output current is being

displayed.
Flashes when the peak output current
is being displayed.

kh Lit when the run time is being

displayed.

°C Lit when the temperature is being

displayed.
s Lit when setting the sequence time.
1 to 4 Lit or flashing when displaying branch

output information. (See note 3.)

10 Mode Key Used to change the parameter being

displayed or to reset the peak hold

current value.

11 Up Key Used to move to diff erent setting

modes or to increase a set value.

12 Down Key Used to move to different setting

modes or to decrease a set value.

13 Reset Key (RST) Used when connecting branch

outputs for tripping operation. (See

note 4.)

14 Communications

Terminals (RD, SD, SG)

Connect to the communications lines

(RS-232C). (See note 5.)

6 Digital Multicircuit Protector S8M

Engineering Data

■Derating Curve

Note: 1. Internal parts may occasionally be deteriorated or damaged. Do not use the S8M in areas outside the derating curve (i.e., in the area

shown by shading A in the above graph).

2. If there is a derating problem, use forced air cooling.

■Abnormal Current Tripping

Standard Detection

S8M-CP04/S8M-CP04-R S8M-CP04-RS

Instantaneous Detection

S8M-CP04/S8M-CP04-R S8M-CP04-RS

1

120

100

80

60

40

20

0

−100 10203040 6050 70−20
Ambient temperature (°C)

Maximum applied current for

any one branch output (%)

S8M-CP04, S8M-CP04-R: Maximum output current 4.0 A
S8M-CP04-RS: Maximum output current 3.8 A

Derating Curve of the S8M

The ambient temperature that S8M can be
operating is limited by the maximum output
current of one branch terminal on ordinary
current condition.

4

100

Time (ms)

Current

(A)

Characteristics when steady

Current limited by
internal circuit

Tripping region

Setting

range

6

20

120.5

Characteristics when steady

Current limited by
internal circuit

Tripping region

Setting

range

3.8

100

Time (ms)

Current

(A)

6

20

12

0.5

Characteristics when steady

Current limited b

y

internal circuit

Setting

range

Tripping region

Time (ms)

20

4

Current (A)

120.5

20

3.8 120.5

Characteristics when steady

Current limited b

y

internal circuit

Setting

range

Tripping region

Time (ms)

Current

(A)

Digital Multicircuit Protector S8M 7

■Mounting

Note: 1. Improper mounting will interfere with heat dissipation and may occasionally result in deterioration or damage of internal parts.

Do not use any mounting method other than the standard one.

2. Take adequate measures to ensure proper heat dissipation to increase the long-term reliability of the S8M.

3. Install the S8M so that the air flow circulates around it, because the S8M is designed to radiate heat by means of natural air flow.

Functions

■Functions

Standar d Mounting

Correct

Face-up Mounting

Incorrect

Alarm Alarm output Output status Alarm display

Abnormal voltage tripping TRP output: OFF

(normally ON )

All branch outputs cut off. A10

Abnormal current tripping TRP output: OFF

(normally ON )

Relevant branch output cut
off.

A11

Overvoltage alarm ALM output: OFF

(normally ON )

ON A20

Undervoltage alarm ALM output: OFF

(normally ON )

ON A21

Overcurrent alarm ALM output: OFF

(normally ON )

ON A22

Run time alarm ALM output: OFF

(normally ON )

ON A23

Over-temperature output TMP output: OFF

(normally ON )

ON A30

8 Digital Multicircuit Protector S8M

■Tripping Functions

Note: 1. Two abnormal current tripping types are supported depending on the tripping current characteristics: Standard detection and

instantaneous detection. Select the required tripping type.

2. Outputs are cut off using semiconductor relays and electrical insulation is not provided.

3. The output will remain OFF and the alarm display and alarm output will not be cleared even if power is restored. The S8M must be reset

to restore operation. (Refer to List of Alarms on page 16 for details.)

4. The voltage at the power input terminals is monitored to detect abnormal voltages. To confirm correct output voltages, measure the
voltages at the branch output terminals.

Chart 1: Operation Timing Chart 2: Operation Timing

Function Operation

Abnormal voltage tripping
Refer to Chart 1.
(See notes 2, 3 and 4.)

The input voltage is monitored and all branch outputs are cut off if the detection voltage is reached. Notification of the
status is provided using the alarm display and the tripping alarm output (TRP).

The alarm display will alternate between the voltage and the alarm code (A10). The primary voltage is measured at
the input terminals.

Detection voltage: 28.8 V (fixed)

Abnormal current tripping
Refer to Chart 2.
(See notes 2 and 3.)

The output current is monitored and the branch output that is abnormal is cut off if the preset current is reached.
Notification of the status is provided using the alarm display and the tripping alarm output (TRP).

The alarm display will alternate between the current and the alarm code (A11).
Abnormal current detection setting range: 0.5 to 4.0 A (S8M-CP04-RS: 0.5 to 0.38 A) in 0.1-A units.
Either of two abnormal current tripping types can be set.
Standard detection: Tripping within 100 ms. (If a current exceeding the set v alue flo ws for 80 ms or more, it is detected

as an abnormal current and power is cut off within 20 ms.)

Instantaneous detection: Tripping within 20 ms. (If a current exceeding the set value flows for 10 ms or more, it is

detected as an abnormal current and power is cut off within 10 ms.)

(Refer to page 14 for the setting procedure.)

T ripping by e xternal signal
(See note 2.)

The output can be cut off by inputting a voltage to the external tripping input (TRG terminal). If a shutdown sequence
has been set, outputs will be cut off according to the shutdown sequence. (Refer to page 14 for information on the
shutdown sequence.)

External input signal width: 10 ms min.
External tripping enable/disable setting: Enabled
Input signal levels

High level: 19.2 to 30 VDC

Low level: 0 to 2.5 VDC
Tripping can also be performed by using communications (S8M-CP04-R/RS only).
Refer to the S8M User’s Manual (Cat. No. Z241) for information on tripping using communications.

28.8 V (Abnormal voltage tripping)

25 V (Overvoltage alarm)

18 V (Undervoltage alarm)

0

24 V (Rated)

Alarm display

Tripping alarm output
(See note.)

Reset

Alarm output
(See note.)

(Fixed)

(Settable)

(Settable)

100 ms 100 ms

t

A21 A20 A10

20 ms

3 s

Note: The alarm and tripping alarm output are both transistor outputs.

It is normall

y

ON and turns OFF when an alarm is detected.

t

(Settable)

(Settable)

4.0 A

(Abnormal current tripping)

3.5 A

(Overcurrent alarm)

3.0 A

(Normal current)

0

Alarm display

Alarm output
(See note.)

Tripping alarm output
(See note.)

Reset

20 ms

(Instantaneous)

3 s

100 ms

(Standard)

Within 20 ms for instantaneous
detection and 100 ms for standard
detection (depends on tripping type).

A22 A22 A11

Note: The alarm and tripping alarm output are both transistor outputs.

It is normally ON and turns OFF when an alarm is detected.

Digital Multicircuit Protector S8M 9

■Alarm Functions

Note: 1. Branch outputs are not cut off for the alarm functions.

2. The voltage at the power input terminals is monitored to detect abnormal voltages. To confirm correct output voltages, measure the

voltages at the branch output terminals.

Chart 3: Operation Timing Chart 4: Operation Timing

Function Operation

Overvoltage alarm
(Refer to Chart 1.)
(See notes 1 and 2.)

The voltage is monitored and notification is provided using the alarm display and output (ALM) if the preset
voltage is exceeded for more than 100 ms. The alarm display will alternate between the voltage and the alarm
code (A20). The primary voltage is measured at the input terminals.

Overvoltage alarm setting range: 20.0 to 28.8 V in 0.1-V units.
(Refer to page 14 for the setting procedure.)

Overcurrent alarm
(Refer to Chart 2.)
(See note 1.)

Each branch output current is monitored and notification is provided using the alarm display and output (ALM) if
the preset value is reached.

The alarm display will alternate between the current and the alarm code (A22).
Overcurrent alarm setting range: 0.5 to 4.0 A (S8M-CP04-RS: 0.5 to 0.38 A) in 0.1-A units.
Either of two tripping types can be set.
Standard detection: An alarm is output if the current exceeds the set value for 80 ms or longer.
Instantaneous detection: An alarm is output if the current exceeds the set value for 10 ms or longer.
(Refer to page 14 for the setting procedure.)

Undervoltage alarm
(Refer to Chart 1.)
(See notes 1 and 2.)

The voltage is monitored and notification is provided using the alarm display and out put (ALM) if the voltage drops
below the preset voltage for more than 80 ms. The alarm display will alternate between the voltage and the alarm
code (A21). The primary voltage is measured at the input terminals.

Undervoltage alarm setting range: 18.0 to 26.4 V in 0.1-V units.
(Refer to page 14 for the setting procedure.)

Run time alarm
(Refer to Chart 3.)
(See note 1.)

The time that the power is turned ON is calculated as the S8M run time and notification is provided using the
alarm display and output (ALM) if the preset time is reached. The alarm display will alternate between the run
time and the alarm code (A23).

Display range: 0.0 to 99.9 kh in 0.1-kh units.
Run time setting range: 0.0 to 99.9 kh in 0.1-kh units.
(Refer to page 14 for the setting procedure.)

Over-temperature output
(Refer to Chart 4.)
(See note 1.)

The internal temperature of the S8M is monitored using a built-in temperature sensor and notification is provided
using the alarm display and over-temperature output (TMP) if the preset temperature is exceeded for more than
1 s. The alarm display will alternate between the temperature and the alarm code (A30). The over-temperature
output is convenient f or control operations , such as operating a cooling fan to suppress temperature increased in
the control panel.

Note: The alarm display and over-temperature output are automatically cleared if the temperature fal ls below the
set temperature.

Display range:

−10 to 100°C in 1°C units.

Temperature setting range: 25 to 80

°C in 1°C units.

(Refer to page 14 for the setting procedure.)

t

(Settable

)

Run time

50.0 kh

Note: The alarm output is a transistor output. It is normally ON and
turns OFF when an alarm is detected.

Power ON

Alarm display

Alarm output
(See note.)

Run time cleared

0

A23

(Settable)

t

Temperature

50°C

0

Alarm display

Over-temperature
output (See note.)

A30 A30 A30

Note: The alarm display and over-temperature output are automatically cleared (with

hysteresis). (Refer to page 16.) The over-temperature output is a transistor output.
It is normall

y

ON and turns OFF when an alarm is detected.

10 Digital Multicircuit Protector S8M

■Other Functions

Note: The sequencing functions are designed for the four branch out puts of one S8M. There is no sync processing between S8M Protectors when

more than one S8M is used.

Chart 5: Operation Timing Chart 6: Operation Timing

Function Operation

Startup sequence
(Refer to Chart 5.)

The connection timing for branch outputs 1 to 4 can be set individually to offset the connection timing of load

devices. Creating time delays between starting loads enables safe load operation. It also reduces total inrush

current so that power supply capacity can be optimized.

Setting range: 0.0 to 99.0 s in 0.1-s units. (See note.)

(Refer to page 14 for the setting procedure.)

Shutdown sequence
(Refer to Chart 6.)

The cutoff timing for branch outputs 1 to 4 can be set individually to offset the cutoff timing of load devices for the

external tipping input or to enable an emergency stop.

Setting range: 0.0 to 99.0 s in 0.1-s units. (See note.)

(Refer to page 14 for the setting procedure.)

Startup delay A delay function is provided so that the abnormal current tripping

function or overcurrent alarm function will not be triggered by large

initial surge currents, e.g., for capacitive loads or lamp loads. The

abnormal current tripping function will function once the set time has

elapsed.

(Note: The delay is fixed at 70 ms.)

t

Current

0

70 ms: Delay

Alarm function disabled
for large surge currents
at startup.

Power supply voltage

Startup sequence time

Startup sequence time

Startup sequence time

Startup sequence time

Self-diagnosis

(0.5 s min.)

Branch output 1 voltage

Branch output 2 voltage

Branch output 3 voltage

Branch output 4 voltage

Shutdown sequence time

Shutdown sequence time

Shutdown sequence time

Shutdown sequence time

Within 20 ms

External tripping input

Branch output 1 voltage

Branch output 2 voltage

Branch output 3 voltage

Branch output 4 voltage

Note: Tripping operation is simultaneous for tripping made for
abnormal volta

g

es (28.8 V or higher).

Digital Multicircuit Protector S8M 11

■Key Operations and Displa ys in Each Mode

Input Voltage

Display

Run Mode

Mode Selection

Menu

Run Mode Setting Mode Test Mode Protection Level Parameter Initialization

Level Selection Yes, initialize.

Output Current

Display

(See note.)

Peak Output

Current Display

Clearing selected

peak output current.

Or no key operation for
more than 3 s.

Or no key operation for
more than 5 s.

Or no key operation for
more than 3 s.

Press for 3 s.

Press for 3 s. Press for 3 s.

Press for 3 s.

Press for 3 s.

Total Current

Display

Run Time Display

Temperature

Display

Abnormal Current

T ripping V alue

Abnormal Current

T ripping Type

Overcurrent
Alarm Value

Overcurrent

Alarm T ype

Undervoltage

Alarm Value

Setting Mode

Power ON

(See note.)

Standard/

Instantaneous

Value Setting

No key operation for more than 3 s.

No key operation for more than 3 s.

Standard/

Instantaneous

Value Setting

No key operation for more than 3 s.

No key operation for more than 3 s.

Value Setting

No key operation for more than 3 s.

Overvoltage
Alarm Value

Value Setting

No key operation for more than 3 s.

Run Time

Alarm Value

Value Setting

No key operation for more than 3 s.

Over-temperature

Output Value

Value Setting

No key operation for more than 3 s.

Startup Sequence

Time Setting (See note.)

Time Setting

No key operation for more than 3 s.

Shutdown Sequence

Time Setting (See note.)

Time Setting

No key operation for more than 3 s.

External Tripping Input

Setting (See note.)

Enable/Disable

Setting

No key operation for more than 3 s.

Communications Settings

(Models with

communications only)

Settings

No key operation for more than 3 s.

Clearing

the Run Time

YES/NO

Connected

Branch Output 1

Cut off

Connected

Cut off

Connected

Cut off

Connected

Cut off

Branch Output 2

Branch Output 3

Branch Output 4

Cut off all branch outputs

(Shutdown Sequence)

Execute

Execute

Connect all branch outputs

(Startup Sequence)

Test Mode

When power was turned
ON for the first time

When power was
turned OFF in
Test Mode

Note: Settin

g

s are displayed in order for branch outputs 1 to 4. Specific branch output settings have been omitted.

When power was turned
OFF in any mode except
Test Mode

12 Digital Multicircuit Protector S8M

■Mode Descriptions

The S8M supports a Run Mode, Setting Mode, and Test Mode.

Note: Refer to the S8M User’s Manual (Cat. No. Z241), when having

further setting.

■Initial Settings When First Using

the S8M

The following diagram illustrates mode transitions f or the S8M. When
the S8M is turned ON for the first time, it will enter Setti ng Mode. First
set the required initial settings for the parameters in Setting Mode
and then switch to Test Mode or Run Mode.

■Mode Selection Menu

The following modes can be selected from the Mode Selection Menu
using the Up and Down Keys.

Run Mode Used for normal operation.
Setting Mode Used to set or change S8M parameters.
Test Mode Used to test operation for devices connected to the

S8M.

When powe

r

was turned
OFF in Test
Mode

When power was
turned OFF in any
mode except Test
Mode

Mode Selection Menu

Run Mode run (RUN)

Setting Mode set (SET)

Test Mode tst (TST)

Protection Level prt (PRT)

Parameter Initialization ini (INI)

Press for 3 s.

Press for 3 s.

Press for 3 s.

Test Mode

Run Mode

Setting Mode

Power ON

(1) Run Mode

(2) Setting Mode

(3) Test Mode

(4) Protection Level

(5) Parameter Initialization

In Run Mode, the current, input voltage, and other values are displayed
for the branch outputs.
Use this mode for operation once initial settings and system
adjustments have been completed.

Setting Mode is used to set parameters.
Operation starts from this mode when using the S8M for the first time.

Test Mode enables forcing branch outputs ON and OFF.
Connections and cutoffs can be manipulated for all outputs for each
branch output.
By default, all outputs will be OFF.
Test Mode is thus used to turn ON branch outputs as required.

Protection Level can be used to set restrictions for reading and writing
parameters. Three levels, levels 0, 1, and 2, are available.
The default is level 1. Refer to the S8M User's Manual (Cat. No. Z241)
for the parameters that are protected in each level.

Parameter Initialization is used to return all parameters to their default
settings. The Parameter Initialization is not displayed in the default
protection level (level 1), and the protection level must be set to level 0
to initialize parameters. Refer to the S8M User's Manual (Cat. No. Z241)
if initialization is required.

Digital Multicircuit Protector S8M 13

■Run Mode

Run Mode is used for normal operation. When the input power is
turned ON and the mode was Run Mode or Setting Mode the last
time the input power was turned OFF, the S8M will start in Run Mode
and connecting the branch outputs will be started. Monitoring of the
voltages, currents, run time, and temperature can be confirmed using
the Up Key and Down Key ( and ).

Note: 1. The S8M will start in Setting Mode when power is turned ON

for the first time after shipping from the factory.

2. Settings cannot be changed in Run Mode. Use Setting
Mode to change settings.

3. If a startup sequence has been set, connections will be
started according to the set delays.

4. When moving to Run Mode, the branch output ON/OFF
status from before entering Run Mode will be maintained.
When switching to Run Mode from Test Mode, first turn ON
all of the branch outputs.

5. The voltage detection function monitors the voltage at the
power input terminals. Measure the voltage at the branch
output terminals to confirm that the output voltage is correct.

Status Indicators

The status indicators light according to the branch output status as
described below.

Clearing the Peak Output Currents

The peak output currents can be cleared. Select the peak output
current to be cleared in Run Mode and then use the following
operation.

1234VAkh°C

°C

°C

°C

°C

°C

s

1234VAkh s

1234VAkh s

1234VAkh s

1234VAkh s

1234VAkh s

(1) Input Voltage Display

(2) Output Current Display for Branch Output 1

(3) Peak Output Current Display for Branch Output 1

(4) Total Current Display

(5) Run Time Display

(6) Temperature Display

The output current for a branch output is displayed.

The total current for all four branch outputs is
displayed.

The S8M run time is displayed.

The temperature inside the S8M is displayed.

The input voltage is monitored and displayed.

The peak output current for a branch output is
displayed.
The output currents and peak output currents for
branch outputs 2 to 4 are displayed next.

Lit green Normal connection status
Flashing green Connection standby status during the star tu p

sequence

Lit red Cutoff status for an abnormality
Flashing red Cutoff status for a redundant protection circuit with

Class 2 specifications

Not lit Forced cutoff or operation stopped

Status Indicators

Peak Output Current Display

Clearing completed.

Set value saved (flashes for 3 s)

Waiting display, 1 s

1234VAkh°Cs

1234VAkh°Cs

1234VAkh°Cs

1234VAkh°Cs

1234VAkh°Cs

After flashing

for 3 s

or

3 s with

no key operations

Note: Indicator Status Notation

: Lit : Flashing

14 Digital Multicircuit Protector S8M

■Setting Mode

Setting Mode is used to set S8M parameters. Settings can be read or changed while operation continues. The various parameters can be selected
as shown below.

Abnormal Current Tripping Type

Overcurrent Alarm Value

Abnormal Current Tripping Value

Undervoltage Alarm Value

Overvoltage Alarm Value

Run Time Alarm Value

Over-temperature Output

Startup Sequence (See note 4.)

Overcurrent Alarm Type

Unit No.

Communications Settings (See note 4.)

Bit Length

Stop Bits

Parity

Send Wait Time

Clearing the Run Time (See note 5.)

Baud Rate

Detection settings for currents to cut off branch outputs.
Standard detection/instantaneous detection

Detection settings for currents to cut off branch outputs.
Standard detection/instantaneous detection

Enable/disable the startup sequence and set the time
for each branch output.
Time setting range: 0.0 to 99.9 s

Unit number setting (0 to 31)

Baud rate setting
48: 4,800 bps, 96: 9,600 bps

Bit length setting (7 or 8)

Stop bit setting (1 or 2)

Parity setting
non: None, evn: Even, odd: Odd

Send wait time setting
0 to 999 ms

The run time can be cleared.

C-V

C-T

A-V

A-T

V-U

V-O

TIM

TMP

UPS

UNO

BPS

LEN

BIT

PTY

SWT

CLR

Repeated for each branch output.

Repeated for each branch output.

Repeated for each branch output.

Repeated for each branch output.

Shutdown Sequence (See note 4.)

Enable/disable the shutdown sequence and set the time
for each branch output.
Time setting range: 0.0 to 99.9 s

DWS

External Tripping Input (See note 4.)

Enable/disable the external tripping inpu

t

TRG

The current at which a branch output is cut off.
Setting range: 0.5 to 4.0 A (S8M-CP04-RS: 0.5 to

3.8 A) The branch output will be cut off if the value
set here is exceeded.

The current at which an alarm is output.
Setting range: 0.5 to 4.0 A (S8M-CP04-RS: 0.5 to

3.8 A)
An alarm will be output if the value set here is
exceeded.

The detection value for a voltage drop at which an
alarm is output.
Setting range: 18.0 to 26.4 V
An alarm will be output if the voltage drops below the
value set here.

The detection value for a voltage rise at which an
alarm is output.
Setting range: 20.0 to 28.8 V
An alarm will be output if the voltage rises above the
value set here.

The run time at which an alarm is output.
Setting range: 0.0 to 99.9 kh
An alarm will be output if the value set here is
exceeded.
The alarm will be disabled if the alarm value is set to

0.0.

The temperature at which an signal is output.
Setting range: 25 to 80°C
An over-temperature signal will be output if the value
set here is exceeded.

(See note 4.)

(See note 4.)

Note: 1. Parameters cannot be changed in protection level 2.

2. The S8M will start in Setting Mode when power is turned ON for the

first time after shipping from the factory.

3. Refer to the S8M User's Manual (Cat. No. Z241), when having
further settings.

4. Not displayed in protection level 1 or 2.

5. Not displayed in protection level 2.

Setting Parameters

Parameters are set as shown below.

Example for Setting the Abnormal Current Tripping Value

Set value saved (flashes for 3 s).

1234VAkh°Cs 1 2 3 4 VAkh°Cs

1234VAkh°Cs

After flashing
for 3 s

When finished, press to
save the set value.

Use to change the set value.

After no key

operations for

3 s

Note: Indicator Status Notation

: Lit : Flashing

Clearing the Run Time

The run time can be cleared. Select the run time to be cleared in Run
Mode and then use the following operation.

Clearing the Run Time

Set value saved (flashes for 3 s)

Waiting display, 1 s

1234VAkh°Cs

1234VAkh°Cs

1234VAkh°Cs

1234VAkh°Cs

After flashing

for 3 s

or

3 s with

no key operations

Digital Multicircuit Protector S8M 15

■Test Mode

Device startup operation can be tested by turning ON/OFF branch
outputs either individually or together. The branch outputs that are to
be used are set to be connected in Test Mode. The operation to turn
all branch outputs ON/OFF together can be used to check startup
and shutdown sequences.

1. Turning ON/OFF Individual Branch Outputs

The following display will appear when Test Mode is entered and the
Up and Down Keys ( and ) can be used to select the branch
output. Set the branch output number to be output, confirming the
number on the mode indicators, and then turn ON the output. The
ON/OFF (connected/cut off) status of the branch outputs can be
confirmed on the status indicators. An indicator will light green if the
output is connected normally.

2. Turn ON/OFF All Branch Outputs

The Up and Down Keys ( and ) can also be used to select all
branch output numbers. The ON or OFF display will appear . Use the
Mode Key to execute the operation.

Note: Test Mode can be entered only in protection level 0 or 1.

It cannot be entered in protection level 2.

■Protection Level Setting

A protection level can be set to prevent operating errors during
normal operation. Reading or changing parameter settings and other
operations can be restricted in three levels.

Select PRT (protection level) from the Mode Selection Menu and
then perform the following procedure. (The following example shows
changing to protection level 0.)

■Parameter Initialization

All S8M parameters can be restored to their default settings. Set
protection level 0 and then go to the Mode Selection Menu. INI
(parameter initialization) will be added to the menu. Select INI and
then perform the following procedure.

Note: 1. The Mode Selection Menu is not displayed in protection

level 1 or 2. The default setting is for protection level 1.

2. Default Settings

• The operating mode will change to Setting Mode.

• The parameters will change to their default settings.

• All branch outputs will be changed so they are not connected.

• The protection level will change to level 1.

Waiting display, 1 s (operation executed)

Waiting for connection (branch output 1 is OFF)

Waiting for cutoff (branch output 1 is ON)

1234VAkh°Cs

1234VAkh°Cs

1234VAkh°Cs

Changes after the
waiting display.

1234VAkh°Cs

1234VAkh°Cs

The all branch outputs will be connected if the Mode
Key ( ) is pressed in this status.
Confirm that the status indicators for all branch outputs
light green.

The all branch outputs will be cut off if the Mode Key
( ) is pressed in this status.
Confirm that the status indicators for all branch outputs
go OFF.

Note: Indicator Status Notation

: Lit : Flashing

Protection

Level

Intended for Possible operations

0 Facility designers

and manufacturers

All settings can be read and
changed.

1 Facility maintenance

personnel

Some settings can be read and
changed.

2 On-site operators S ettings can be read but not

changed.

Setting Protection Level

Mode Selection Menu
(Protection Level)

After no key
operations for
3 s

Run Mode

Set value saved
(flashes for 3 s)

Parameter Initialization

Mode Selection Menu
(Parameter Initialization)

After no key
operations for
3 s

Run Mode

Setting Confirmation
(Flashes for 3 s.)

16 Digital Multicircuit Protector S8M

■List of Alarms

Note: A larms will be displayed in order of priority if more than one alarm occurs at the same time.

Order of priority: A10, A11, A20, A21, A22, A23, A30.

Alarm

display

Name Alarm outputs Power

outputs

Recovery/reset method

A10 Abnormal voltage

tripping

TRP output: OFF
(normally ON)

Cut off Remove the cause of the abnormality and then press the Reset Key( ) on the front

panel for at least 3 s or use communications reset function (S8M-CP04-R/RS only).
Power supply will be restarted after recovery.

Note: 1. Resetting will be possible from 15 s after the output is cut off.

2. Cutoff and alarm status will not be reset even if the power supply is reset.

A11 Abnormal current

tripping

TRP output: OFF
(normally ON)

Cut off Remove the cause of the abnormality and then press the Reset Ke y ( ) on the front

panel for at least 3 s or use communications reset function (S8M-CP04-R/RS only).
Power supply will be restarted after recovery.

Note: 1. Resetting will be possible from 15 s after the output is cut off.

2. Cutoff and alarm status will not be reset even if the power supply is reset.

A20 Overvoltage alarm ALM output: OFF

(normally ON)

ON Remove the cause of the alarm and then press the Reset K ey ( ) on the front panel

for at least 3 s or use communications reset function (S8M-CP04-R/RS only). Run
Mode will be returned to after the alarm is reset.

Note: 1. Resetting will be possible if the voltage remains below the set value minus

0.3 V for at least 500 ms from 15 s after the alarm occurs.

2. The alarm status will be reset if the cause of the alarm has been removed
when the power supply is reset.

A21 Undervoltage

alarm

ALM output: OFF
(normally ON)

ON Remove the cause of the alarm and then press the Reset K ey ( ) on the front panel

for at least 3 s or use communications reset function (S8M-CP04-R/RS only). Run
Mode will be returned to after the alarm is reset.

Note: 1. Resetting will be possible if the voltage remains above the set value plus

0.3 V for at least 500 ms from 15 s after the alarm occurs.

2. The alarm status will be reset if the cause of the alarm has been removed
when the power supply is reset.

A22 Overcurrent alarm ALM output: OFF

(normally ON)

ON Remove the cause of the alarm and then press the Reset K ey ( ) on the front panel

for at least 3 s or use communications reset function (S8M-CP04-R/RS only). Run
Mode will be returned to after the alarm is reset.

Note: 1. Resetting will be possible if the current remains below the set value for at

least 500 ms from 15 s after the alarm occurs.

2. The alarm status will be reset if the cause of the alarm has been removed
when the power supply is reset.

A23 Run time alarm ALM output: OFF

(normally ON)

ON Perform the run time clear operation in Setting Mode.

CLR (run time clear) will be displayed on the Setting Mode Menu and YES/NO will
be displayed when the Mode Ke y ( ) is pressed. The run time will be cleared if the
Mode Key ( ) is pressed again when Yes is displayed.

Note: CLR (r un time clear) will not be displayed on the Setting Mode Menu in

protection level 2. Change the protection level to level 0 or 1 using the
Protection Mode Selection Menu and then clear the run time.

A30 Over-temperature

output

TMP output: OFF
(normally ON)

ON The alarm display and over-temperature output will automatically be reset if the

temperature remains below the set value minus 3

°C for at least 5 s.

Digital Multicircuit Protector S8M 17

■Alarm Display

The S8M displays alarms according to the parameters set in Setting
Mode. The alarm number and detected value are alternated on the
display for each alarm.

Example: Abnormal Current Tripping Alarm

Note: Alarms will be displayed in order of priority if more than one

alarm occurs at the same time.
Order of priority: A10, A11, A20, A21, A22, A23, A30.

■Resetting Alarms

When an alarm is displayed, remove the cause of the alarm and then
press the Reset Key ( ) for at least 3 s. The following display will

appear and the alarm will be reset.
Note: The over-temperature output will automatically be reset when

the temperature drops below the set value. All other alarms
must be reset manually.

■Communications

(S8M-CP04-R/ CP04-RS)

The built-in RS-232C port can be used to connect special Support
Tool to set parameters, monitor, perform tripping operations for
branch outputs, and perform other remote monitoring and control
operations from a network.

■Support Tool

(S8M-CP04-R/ CP04-RS)

The Support Tool is used to set and monitor models that support
communications. Parameters can be set, operation can be
monitored, and parameter files can be managed.

Support Tool Functions

• Reading and writing parameter settings

• Monitoring present values

• Monitoring status (cutof f status, norm al/error status)

Applicable OS: Windows 2000 or XP

Visit OMRON's website for downloading the Support Tool.

Nothing displayed

Current when alarm occurred

1234VAkh°Cs 1234VAkh°Cs

1234VAkh°Cs

0.5 s

0.5 s

0.5 s 0.5 s

Note: Indicator Status Notation

: Lit : Flashing

To Run Mode

Run Mode is returned to automatically when the alarm is reset.
Refer to List of Alarms on page16 for recovery/resetting

methods.

Type RS-232C
Communications method Half-duplex
Sync method Start-stop
Baud rate 4,800 or 9,600 bps
Transmitted code ASCII
Data bit length 7 or 8 bits
Stop bit leng th 1 or 2 bits
Error detection Vertical parity and BCC
Parity che ck None, even, or odd
Protocol CompoWay/F

18 Digital Multicircuit Protector S8M

Dimensions

Note: A ll units are in millimeters unless otherwise indicated.

Note: The image is the S8M-CP04-RS Model.

75

4.1

115

Two, M4 screws with
square washers

Eight, M3.5 screws with
square washers

86.5

8.7

4.35

94

Digital Multicircuit Protector S8M 19

■DIN Rail (Order Separately)

Note: All units are in millimeters unless otherwise indicated.

4.5

15 25 25

10 10

1,000 (500)
(See note.)

25 25 15 (5)

(See note.)

35

±0.3

7.3±0.15

27±0.15

1

Note: Values in parentheses are for the PFP-50N.

M

ounting Rail (Material: Aluminum

)

PFP-100N
PFP-50N

4.5

15 25 25

10 10

1,000

25 25 15

11.5

29.2242735

±0.3

16

M

ounting Rail (Material: Aluminum

)

PFP-100N2

1.3

4.8

35.5

35.5

1.8

1.8

M4 spring washer

10

6.2

1

50

M4 × 8
pen-head
screw

11.5
10

End Pl

ate

PFP-M

20 Digital Multicircuit Protector S8M

Safety Precautions

!CAUTION

■Precautions for Safe Use

Mounting

Take adequate measures to ensure proper heat dissipation to
increase the long-term reliability of the S8M. Install the S8M so that
the air flow circulates around it, because the S8M is designed to
radiate heat by means of natural air flow.

Improper mounting will interfere with heat dissipation and may
occasionally result in deterioration or damage of internal parts. Do
not use any mounting method other than a standard one.

Side-by-side mounting of two or more S8M is possible. The switch
mode power supply connected to inputs and any other sources of
heat, however, must be separated as shown below.

Wiring

Minor electric shock during operation may occasionally occur.
Always attach the terminal cover when using the S8M.

Minor fire may possibly occur. Ensure that input and out put terminals
are wired correctly.

Increases in the temperature of internal parts resulting from heating
of wiring materials may result in deterioration or damage to internal
parts. Use wiring materials suitable to the current being used. The
following wiring materials, torque and strip length are recommended
to prevent heating and possible fires in wiring materials.

Recommended Wire Types

Do not apply more than 100 N force to the terminal block when
tightening screws.

Be sure to remove the sheet covering the S8M for machining before
power-ON so that it does not interfere with heat dissipation.

Installation Environment

Do not use the S8M in locations subject to shocks or vibrations. In
particular, install the S8M as far away as possible from contactors or
other devices that are vibration sources. Additionally, install a PFP-M
End Plate on each end of the S8M.

Install the S8M well away from any sources of strong, high frequency
noise and surge.

Operating Life

The life of the S8M is determined by the life of the electrolytic
capacitors used inside. Here, Arrhenius Law applies, i.e. , the life will
be halved for each rise of 10

°C or the life will be doubled for each

drop of 10

°C. The life of the S8M can thus be increased by reducing

its internal temperature.

Ambient Operating and Storage
Environment

Store the S8M at a temperature of −25 to 65°C and a humidity of
25% to 90%.

Internal parts may occasionally be deteriorated or damaged. Do not
use the S8M in areas outside the derating curve (i.e., in the area
shown by shading ( ) in the derating curve diagram on

page 6).
Surrounding air temperature for UL 508 Listing and UL60950-1
Recognition is 50

°C.

Use the S8M at a humidity of 25% to 85%.
Do not use the S8M in locations subject to direct sunlight.
Do not use the S8M in locations where liquid, foreign matter, or

corrosive gases may enter the S8M.

Minor electric shock, fire, or Product failure may
occasionally occur. Do not disassemble, modify, or repair
the Product or touch interior of the Product.

Minor burns may occasionally occur. Do not touch the
Product while power is being supplied or immediately
after power is turned OFF.

Fire may occasionally occur. Tighten terminal screws to
the specified torque.

Power input terminals: M4 1.08 N·m (9.6 in. lb.)
Branch output terminals: M3. 5 0.8 to 1.0 N·m

(7.2 to 8.8 in. lb.)

Minor electric shock, fire, or Product failure may
occasionally occur. Do not allow any pieces of metal or
conductors or any clippings or cuttings resulting from
installation work to enter the Product.

The Product will be damaged. Do not incorrectly connect
the polarity of power input terminals.

(See note 1.)

(See note 2.)

(See note 3.)

(See note 1.)

(

See note 4.

)

Note: 1. Convection of air

2. 75 mm min.

3. 75 mm min.

4. 10 mm min.

Terminals Wiring materials Torque Strip

length

Power input
terminals

AWG14
(2.081 mm

2

) × 2

Solid,
Stranded

1.08 N·m
(9.6 in. lb.)

8 to 10 mm

Branch
output
terminals

AWG16 to 20
(1.309 to

0.517 mm

2

)

0.8 to 1.0 N·m
(7.2 to

8.8 in. lb.)

6 to 7 mm

Other
terminals

AWG18 to 26
(0.823 to

0.129 mm

2

)

--- 10 mm

Digital Multicircuit Protector S8M 21

Input Voltage

Input voltage range: 19.2 to 26.4 VDC
The S8M provides abnormal voltage protection. All branch outputs

will be cut off if the input voltage exceeds 28.8 VDC. This function,
however , does not protect loads and internal parts from high voltages
in all cases. Be sure the input voltage is within the rated range.

Outputs may be cut off by the abnormal voltage protection with loads
that generate reverse peak electromotive force.

The S8M operates by DC input. Do not connect AC input to power
input terminals.

Input Power Supply Selection

The overcurrent protection characteristics of the power supply
connected to the input side can cause a voltage drop, resulting in
tripping.

If the capacity of the input power supply is too small compared with
the load, the overcurrent protection characteristics of the power
supply can cause the failure of S8M operating or tripping by voltage
drop occasionally.

If the input power supply starts or stops too slowly, the overcurrent
protection characteristics of the power supply can cause the failure of
S8M operating or tripping by voltage drop occasionally.

Tripping Performance

When abnormal tripping operates, always remove the cause of the
output first and then reset the alarm.

When using a load with a fixed power operation, the S8M may cause
tripping when the power supply is turned OFF.

Internal parts may possibly be deteriorated or damaged. Do not
repeatedly perform tripping or recovery operations more than
necessary.

Tripping performance depends on the ambient operating
temperature. Use the S8M within the derating curve shown in the
derating curve diagram on page 6.

Dielectric Strength Test

The S8M is designed to withstand 500 VA C f or 1 min ute between I /O
terminals, all output signal terminals, the external tripping input
terminals, and all communications terminals of the S8M.

The S8M may possibly be damaged from the impulse voltage if a
testing device switch is used to abruptly apply or shut off 500 VAC.
Increase the applied voltage gradually using the voltage adjustment
on the testing device.

Always short the specified terminals so that the voltage is applied to
all of the terminals at the same time.

Power input terminals and branch output terminals are not isolated.
Do not perform dielectric strength tests or other insulation appraisal
testing between inputs and outputs.

External Tripping Input

When using the external tripping input, always confirm the
application methods described in the S8M User's Manual (Cat. No.
Z241) before designing the system.

Display

The voltage detection function monitors the voltage at the power
input terminals. Measure the voltage at the branch output terminals
to confirm that the output voltage is correct.

Backup Device Connections

Observe the following precautions when using a backup de vice, such
as one from OMRON's S8T Series.

• When connecting a backup device to an S8M branch output, the
backup current will be supplied to other branches through internal
circuits and it is conceivable that internal parts may be deteriorated
or damaged at the same time. When using a backup device with
the S8M, connect the backup device to the power input side.

• When connecting a backup device to the S8M input side, the
backup time will be shorter than normal due to internal power
consumption. Always confirm the backup time when using a
backup device.

Startup Delay

The startup delay will not operate when a relay or other device is
used for ON/OFF control on the output side of the S8M, so a tripping
operation may occasionally occur.

Connections

It is possible to connect S8M like below.

Series connections, such as connecting an S8M to the output of
another S8M, are not possible.

+V

−V

+V

−V

+V

−V

−V

+V

−V

+V

−V

+V

−V

+V

−V

+V

−V

+V

−V

+V

−V

+V

Power
supply

S8M

S8M

Correct

Incorrect

+V

−V

−V

+V

−V

+V

−V

+V

−V

+V

V

V

+V

−V

Power
supply

S8M

S8M

22 Digital Multicircuit Protector S8M

Troubleshooting

If the S8M is not operating properly, check the items listed in the following table before requesting repairs.

Stage Observed problem Possible cause Remedy

Installation The S8M was installed on a DIN Rail,

but the bottom of the Unit is not
attached.

The S8M's bottom latch is not mounted
properly.

Check that the S8M has been pressed
until the bottom latch clicks.

Parameter setting The desired alarm value is not being

displayed.

The setting is not allowed in the present
protection level.

Change the protection level setting.

The set value was changed, but the
change wasn't accepted.

The new setting was not saved. After pressing the Up and Down Keys to

change the set value, press the Mode
Key and verify that the setting flashes
and the setting is saved.

When the S8M was switched to Run
Mode after setting the overvoltage
alarm and undervoltage alarm, the
alarm output went OFF and cannot be
cleared.

The undervoltage and overvoltage
settings may have been reversed.

Switch to Setting Mode and check the
settings.

Equipment setup The display is flashing “ON” in Test

Mode, but power is not being supplied
by the outputs.

A flashing “ON” display indicates that
the S8M is waiting to turn ON the
outputs.

If the Mode Key is pressed, the output
will be connected and power will be
supplied.When power is being
supplied, “OFF” will flash on the display .

The S8M was turned OFF in Test Mode,
and there was no power from the
outputs when the S8M was turned ON
again.

If the power is turned OFF in Test
Mode, all of the branch outputs are cut
off for safety reasons.

Either connect all branch outputs in
Test Mode or connect each branch
output individually.

When the output is connected in Test
Mode, it is cut off immediately and can't
be connected again.

Check whether the status indicator is lit
red. The current may be higher than the
tripping current.

Check for problems such as output
wiring problems.If no problems are
found, press the Reset Key for at least
3 s.

Operation The displayed temperature is clearly

different from the ambient temperature.

The S8M detects the Unit's internal
temperature, which can be 5 to 10

°C

higher than the ambient temperature.

When the alarm is being used as a
control signal for a fan or cooling
equipment, set the alarm value based
on the graph in the S8M User’s Manual
(Cat. No. Z241).

An alarm was output and the cause of
the alarm was eliminated, but the alarm
display cannot be cleared.

The S8M doesn't disregard temporary
errors, so the alarm display is retained
even after the cause of the alarm is
cleared.

The alarm can be cleared by pressing
the Reset Key for at least 3 s.

The peak output current value is not
displayed and the display shows “- - -”.

The current may have exceeded the
measurable range.

Clear the peak output current value in
Run Mode.

The circuit was not designed for a
current that high, but the circuit is cut off
as soon as power is supplied.

The abnormal current tripping type
(detection method) may be set to
“instantaneous.” With instantaneous
detection, an abnormal current is
detected very quickly and the circuit
may be cut off due to excessive current
during equipment operation.

Either change the abnormal current
tripping type from instantaneous to
standard or raise the current tripping
value.

There may be a large number of
devices connected to the output.The
more devices that are connected, the
higher the operating current.

Use the S8M's startup sequence
function to spread out the connections
to the devices (delay the connection of
some devices).

Branch output cut off The connection cannot be reset

immediately after it is cut off.

T o protect the S8M's internal circuits, at
least 15 seconds must pass before a
cut-off output can be reset.

If “RST” is displayed when the Reset
Key is pressed for at least 3 s, the cut­off output can be reset when 15 s has
passed since the output was cut off.

The output was reset, but it was
immediately cut off again.

The original cause of tripping may not
have been eliminated. After resetting
the error, a large current may have
flowed again.

Eliminate the cause of the cutoff and
press the Reset Key for at least 3 s.

Maintenance The r un time alar m went OFF, so the

equipment was checked and other
parts were replaced, but the alarm
could not be cleared.

The S8M continues adding to the run
time. The run time must be reset to 0 in
order to clear the alarm.

Clear the run time.

Digital Multicircuit Protector S8M 23

In the interest of product improvement, specifica tions are sub jec t to c hange witho ut notic e.

ALL DIMENSIONS SHOWN ARE IN MILLIMETERS.

To convert millimeters into inches, multiply by 0.03937. To convert grams into ounces, multiply by 0.03527.

Cat. No. T037-E1-01

OMRON Corporation

Industrial Automation Company
Control Devices Division H.Q.

Power Electronics Department

Shiokoji Horikawa, Shimogyo-ku,
Kyoto, 600-8530 Japan
Tel: [phone]/Fax: [phone]

Printed in Japan
0506-1.5M (0506) (C)

Warranty and Application Considerations

Read and Understand this Catalog

Please read and understand this catalog before purchasing the products. Please consult your OMRON representative if you
have any questions or comments.

Warranty and Limitations of Liability

WARRANTY

OMRON's exclusive warranty is that the products are free from defects in materials and workmanship for a period of one year (or
other period if specified) from date of sal e by OMRON.

OMRON MAKES NO WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED, REGARDING NON-INFRINGEMENT,
MERCHANTABILITY, OR FITNESS FOR PARTICULAR PURPOSE OF THE PRODUCTS. ANY BUYER OR USER
ACKNOWLEDGES THA T THE BUYER OR USER ALONE HAS DETERMINED THA T THE PRODUCTS WILL SUITABLY MEET
THE REQUIREMENTS OF THEIR INTENDED USE. OMRON DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR
IMPLIED.

LIMITATIONS OF LIABILITY

OMRON SHALL NOT BE RESPONSIBLE FOR SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES, LOSS OF PROFITS,
OR COMMERCIAL LOSS IN ANY WAY CONNECTED WITH THE PRODUCTS, WHETHER SUCH CLAIM IS BASED ON
CONTRACT, WARRA NT Y, NEGLIGENCE, OR STRICT LIABILIT Y.

In no event shall the responsibility of OMRON for any act exceed the individual price of the product on which liability is asserted.
IN NO EVENT SHALL OMRON BE RESPONSIBLE FOR WARRANTY, REPAIR, OR OTHER CLAIMS REGARDING THE

PRODUCTS UNLESS OMRON'S ANALYSIS CONFIRMS THAT THE PRODUCTS WERE PROPERLY HANDLED, STORED,
INSTALLED, AND MAINTAINED AND NOT SUBJECT TO CONTAMINATION, ABUSE, MISUSE, OR INAPPROPRIATE
MODIFICATION OR REPAIR.

Application Considerations

SUITABILITY FOR USE

OMRON shall not be responsible for conformity with any standards, codes, or regulations that apply to the combination of
products in the customer's applicatio n or use of the products.

Take all necessary steps to deter m ine the suitability of the product for the systems, machines, and equipment with wh ich i t wi ll
be used.

Know and observe all prohibitions of use appl icable to this product.
NEVER USE THE PRODUC TS FO R AN APPLICATION INVOLVING SERIOUS RISK TO LIFE OR PROPERTY WITHOUT

ENSURING THAT THE SYSTEM AS A WHOLE HAS B EEN DESIGNED TO ADDRESS THE RISKS, AN D THAT THE OMRON
PRODUCTS ARE PROPERL Y RATED AND INSTALLED FOR THE INTENDED USE WITHIN THE OVERALL EQUIPMENT OR
SYSTEM.

Disclaimers

PERFORMANCE DATA

Performance data given in this catalog is provided as a guide for the user in determining suitability and does not constitute a
warranty. It may represent the result of OMRON's test conditions, and the users must correlate it to actual application
requirements. Actual performance is subject to the OMRON Warranty and Limitations of Liability.

CHANGE IN SPECIFICATIONS

Product specifications and accessories may be changed at any time based on improvements and other reasons. Consult with
your OMRON representative at any time to confirm actual specifications of purchased product.

DIMENSIONS AND WEIGHTS

Dimensions and weights are nominal and are not to be used for manufacturing purposes, even when tolerances are shown.