Omron S8T-DCBU-02 User manual

Buffer Block S8T-DCBU-02 1
Buffer Block
S8T-DCBU-02
Prevents Equipment Stoppage, Data Loss,
and Other Problems Resulting from
Momentary Power Failures
• Provides a backup time of 500 ms at an output current of 2.5 A.
• Can be wired to the 24-V output from the S8VS, S82J, S82K,
and S8PS Power Supplies.
• Connects to an S8TS Power Supply via an S8T-BUS03 Bus
Line Connector.
• Parallel connections to up to four Blocks can be used to
increase the backup time and current capacities.
• Complies with SEMI F47-0200 standard.
S8T-DCBU-02
S8TS
Ordering Information
■Buffer Block
■Options (Order Separately)
Bus Line Connector (Connects to Buffer Block)
Note: One package contains 10 S8T-BUS03 Connectors.
Basic Configuration
Connection using Bus Line Connector Connection via Wiring
Input voltage Output voltage
(during backup operation) Output current Model number
24 VDC (24 to 28 VDC) 22.5 V 2.5 A S8T-DCBU-02
Type Number of Connectors Model number
DC bus line 1 Connector S8T-BUS03
10 Connectors (See note.) S8T-BUS13
S8
T-D
C
B
U
-
02
S8
T-B
US03
Bus Line
C
onnector
(Order separatel
y
.
)
S8
T
S
-
060
2
4
@
(Order separatel
y
.
)
Load
Connect to AC lines.
Load
Connect to AC lines.

2Buffer Block S8T-DCBU-02
Specifications
■Ratings/Characteristics
Note: 1. The output characteristics are specified at the power output terminals.
2. Refer to Backup Time on page 10 for details.
3. Refer to Functions on page 7 for details.
4. If the number of S8T-DCBU-02 Buffer Blocks to be connected is “N,” set the detection current to 20 mA ×N.
5. Specified by S8TS-06024@connection.
6. Be sure to mount an End Plate (PFP-M: Order separately) on each end of the Buffer Block. Refer to DIN Tracks on page 14.
7. To comply with UL508 (Class 2: Per UL1310), connect one S8TS-06024@to one S8T-DCBU-02 Buffer Block.
■Reference Value
Item Model S8T-DCBU-02
Input Voltage 24 to 28 VDC
Current Charging 0.4 A
Standby 0.18 A
Output
(See note 1.) Backup operation Output voltage For 24 V: 22.5 V typ., 22.0 V min. For 28 V: 26.4 V typ., 25.8 V min.
Output current 2.5 A
Backup time
(See note 2.) Time required until the voltage drops from the fully charged level down to 21.6 VDC
1,000 ms min. (for an output current of 1.2 A)
500 ms min. (for an output current of 2.5 A)
Additional
functions Output functions
(See note 3.)
READY indicator Yes (color: green)
READY output Yes (relay: 24 VDC, 0.1 A max.)
Backup indictor Yes (color: red)
Backup output Yes (relay: 24 VDC, 0.1 A max.)
Overcurrent protection Reverse-L dropping, automatic recovery, overcurrent detection point: 5.8 to 6.8 A
Overvoltage protection Yes
Parallel operation Possible (4 Blocks max.)
Series operation Not possible
Other Ambient operating temperature Refer to the derating curve in Engineering Data. (with no condensation or icing)
Storage temperature −25 to 65°C
Ambient humidity Operating: 25% to 85%; Storage: 25% to 90%
Dielectric strength (See note 4.) 1.0 kVAC for 1 minute (between all DC connection terminals and GR terminals; Detection
current: 20 mA)
500 VAC for 1 minute (between all DC connection terminals/GR terminals and all signal
output terminals; detection current: 20 mA)
Insulation resistance 100 MΩmin. (between all DC connection terminals and GR terminals) at 500 VDC
Vibration resistance (See notes 5 and 6.) 10 to 55 Hz, 0.375-mm single amplitude for 2 h each in X, Y, and Z directions
Shock resistance (See notes 5 and 6.) 150 m/s2, 3 times each in ±X, ±Y, and ±Z directions
EMI Radiated Emissions Based on EN55011 Class B.
EMS Conforms to EN61000-6-2
Approved standards UL: UL508 (Listing, Class 2: Per UL1310) (See note 7.),
UL60950, UL1604 (Class I/Division 2)
cUL: CSA C22.2 No.14, No.60950, No.213 (Class I/Division 2)
EN/VDE: EN50178 (=VDE0160), EN60950 (VDE0806)
SEMI standard SEMI F47-0200
Weight 450 g max.
Item Value Definition
Reliability
(MTBF) 135,000hrs min. MTBF stands for Mean Time Between Failures, which is calculated according to
the probability of accidental device fail-
ures, and indicates reliability of devices.
Therefore, it does not necessarily repre-
sent a life of the product.
Life
expectancy 10 yrs. min. The life expectancy indicates average op- erating hours under the ambient tempera-
ture of 40°C and a load rate of 50%.
Normally this is determined by the life ex-
pectancy of the built-in aluminum electro-
lytic capacitor.

Buffer Block S8T-DCBU-02 3
Connections
■Block Diagram
S8T-DCBU-02
Operation
■Application
Connectable Power Supplies
The following Power Supplies (SELV Power Supplies) can be con-
nected. When connected to the following Power Supplies, the Buffer
Block will function properly against a momentary power failure of at
least 300 ms. (See note 1.)
S8TS Series: S8TS-06024@
S8VS Series: S8VS-06024@, S8VS-09024@@, S8VS-12024@@,
S8VS-18024@@, and S8VS-24024@@
S82K Series: S82K-03024, S82K-05024, S82K-@09024,
S82K-@10024, and S82K-@24024@
S82J Series: S82J-02524@@, S82J-05024@@,
S82J-10024@@ (See note 2.), S82J-15024@@,
S82J-30024@, and S82J-60024@
S8PS Series: S8PS-05024@@ (See note 2.),
S8PS-10024@@ (See note 2.), S8PS-15024@@,
and S8PS-30024@@
Note: 1. The backup current must be less than 5 A (parallel operation
connection is required if the backup current exceeds 2.5 A)
and the Buffer Block must be fully charged. If three or more
S8T-DCBU-02 Buffer Block are used in parallel operation
and the backup current exceeds 5 A, the momentary power
failure time that can be compensated for will be reduced.
2. When connected to the S82J-10024@@, S8PS-05024@@,
or S8PS-10024@@ Power Supply, the output voltage may
increase by approximately 4 V for approximately 10 to
50 ms after recovery from the momentary power failure. If
any adverse effect is foreseen, connect a diode as shown
below based on the guidelines given below.
Guidelines for Selecting Diode
Type: Schottky barrier diode
Withstanding voltage (VRRM): At least twice the rated output voltage
Forward current (IF): At least twice the rated output current
Electrolytic capacitor Discharging circuit
+
−
BACKUP output
Drive circuit
READY output
+V
−V
DC input/output
DC (+)
DC (−)
Connected to
Bus Line
Connector
Reverse
connection
protection Charging
circuit
Charging
control
circuit
Voltage
detection 1
Voltage
detection 2
Drive circuit
Discharg-
ing con-
trol circuit
Overvoltage
detection
Overcurrent
detection
Voltage
detection
Reverse flow
prevention diode
Reverse
connec-
tion pro-
tection
Detection
resistor
Voltage
detection
BACKUP
status
detection
Voltage
detection
Voltage
detection
Connected
to Bus Line
Connector
AC input
I/O terminal voltage 4 V
S8T-DCBU-02
Power Supply
Diode
−+

4Buffer Block S8T-DCBU-02
Power Supply To Be Connected
The power consumption of the S8T-DCBU-02 is approximately 10 W,
so make sure that the output capacity of the power supply is suffi-
cient.
If the S8T-DCBU-02 is connected to a previously installed power sup-
ply, the voltage may drop due to the power supply's overcurrent pro-
tection, or backup operations may not be possible.
Note: Connect a power supply within the specified derating range,
considering the power consumption of the S8T-DCBU-02.
Selecting the Power Supply
Determining the Output Capacity
1. Checking Capacities of Devices To Be Connected
Check the capacities (W) of the devices to be connected.
2. Calculating the Total Capacity (Including That of the
S8T-DCBU-02 Buffer Block)
The S8T-DCBU-02 Buffer Block will consume the following power.
Add this to the above capacities (W) to obtain the total capacity.
Vin = 24 V: 9.6 W max. (during charging)
Vin = 28 V: 11.2 W max. (during charging)
3. Calculating the Required Output Capacity
Determine the rate of allowance and apply this allowance rate to
the total capacity calculated above to obtain the output capacity
required by the Power Supply. Be sure to provide a sufficient
allowance rate.
Example: Output voltage: 24 V
Capacities of devices: 36 W (output current: 1.5 A)
Allowance factor: 0.8
Required output capacity of the Power Supply > (36 W
+ 9.6 W) ÷0.8 = 57 W
Therefore, an S8TS-06024@Power Supply,
S8VS-06024@Power Supply, or a Power Supply with a
larger capacity is required.
Selecting the Power Supply
1. Checking the Output Hold Time and Restart Time of
the Power Supply
The relation between the momentary power failure time and the
backup time required to compensate the failure is shown in the
following illustration. As shown by the illustration, the backup time
required from the S8T-DCBU-02 Buffer Block depends on the
connected Power Supply even for the same momentary power
failure time.
Relation between Momentary Power Failure and Backup
Time
The output hold time and restart time of each Power Supply are
shown in Power Supply Output Hold Times (Reference Values) on
page 12 and Power Supply Restart Times (Reference Values) on
page 13.
Example: S8T-DCBU-02: 1 Unit
Connected power supply: S8TS-06024@Power Supply
Load current: 1 A
AC current input voltage: 200 VAC
Momentary power failure time: 300 ms
Required backup time > 300 ms + 270 ms - 100 ms =
470 ms
Refer to the graphs under Backup Time on page 10 to
check whether the backup time is sufficient.
2. Selecting the Power Supply
After obtaining the output capacity required for the Power Supply
and checking its output hold time and restart time as described
above, select an appropriate Power Supply from the list under
Connectable Power Supplies on page 3.
Calculate the total of these capacities.
Calculate the required capacity.
Determining the Output Capacity
Select an appropriate Power Supply.
Check the derating curve.
Selecting the Power Supply
Check capacities of devices to be
connected.
Check the output hold time and restart
time.
+=
Calculation of the Total Capacity
Total
capacity
(W)
Capacities
of devices
(W)
Power consump-
tion (W) of the
S8T-DCBU-02
÷>
Calculation of the Total Power Supply Capacity
Required
output capacity
(W) of the
Power Supply
Total
capacity
(W)
Allow-
ance
factor
+−>
Calculation of the Required Backup Time
Required
backup time
Momen-
tary pow-
er failure
time
Restart time
of Power
Supply
Output hold
time of Power
Supply
AC input
I/O terminal voltage
Backup time
Momentary power
failure time
Output hold time of
Power Supply Restart time of
Power Supply

Buffer Block S8T-DCBU-02 5
3. Checking the Derating Curve
Confirm that the total output capacity calculated in step 2, Calcu-
lating the Total Capacity, under Determining the Output Capacity
is within the derating curve of the Power Supply. If the capacity
exceeds the derating curve, increase the Power Supply capacity
or use forced air cooling to reduce the ambient operating temper-
ature.
Mounting
Mounting Direction
Use standard mounting only. Improper mounting will interfere with
heat dissipation and may occasionally result in deterioration of or
damage to internal parts.
Connecting to the S8TS-06024@
When connecting one or more S8T-DCBU-02 Blocks to the
S8TS-06024@using Bus Line Connectors, connect them to either
the left or right end of the Blocks. Heat dissipation will be interfered
with if the S8T-DCBU-02 Blocks are not connected to the end.
Wiring Connections
A load can be connected to either the power supply side or the
S8T-DCBU-02 side.
Note: Use the largest wire size possible and keep the wiring distance
as short as possible. If the voltage drop caused by the wiring
material is too large, the backup operation may not be suffi-
cient.
Input Voltage
Input voltage range: 24 to 28 VDC
Confirm that an input voltage of at least 24 V is being supplied to the
S8T-DCBU-02 input terminals.
Output Voltage
The output voltage for the backup operation is automatically adjusted
internally by detecting the input voltage. The backup operation is
started when the input voltage drops 2 V.
Note: The output voltage during the backup operation is a maximum
of 2 V lower than the voltage input at an input voltage of 24 V.
Serial Connection
Two Blocks cannot be connected in series to increase the output volt-
age to 48 V or to create positive and negative outputs.
Parallel Operation Connection
The output current and backup time for the backup operation can be
increased by connecting Blocks in parallel.
Standard number of Blocks for parallel operation: 2
Maximum number of Blocks for parallel operation: 4
The backup time will be greatly reduced if three or more Blocks are
connected in parallel and the output current for the backup operation
exceeds 5 A. Refer to Backup Time on page 10 for details on the
backup time during parallel operation.
Note: Although the number of Blocks that canbe connected when us-
ing the S8TS-06024@is five when calculated from the current
capacity of the Bus Line Connector, only a maximum of four
S8T-DCBU-02 can actually be connected in parallel.
Using the Bus Line Connector
When connecting to the S8TS-06024@, always use the S8T-BUS03
Bus Line Connector. This Connector connects only the DC lines. It
does not connect AC lines.
S8T-BUS03 Bus Line Connector
The S8T-BUS03 Bus Line Connector is equipped with a selector to
prevent incorrect connection to a power supply unit with a different
output voltage specification. Slide the selector to the 24 V position.
Standard mounting Yes
Back-down mounting No
Other mounting No
Correct
Standard mounting Incorrect
Back-down mounting
DCON
DCLOW
DCLOW
V.ADJ
+V
-V
L
LN
N
50/60Hz
AC100
-240V
Class2
Power
Supply
DC24V
2.5A
INPUT
OUTPUT
1.0A
+V-V
DCON
DCLOW
DCLOW
V.ADJ
+V
-V
L
LN
N
50/60Hz
AC100
-240V
Class2
Power
Supply
DC24V
2.5A
INPUT
OUTPUT
1.0A
+V-V
DCON
DCLOW
DCLOW
V.ADJ
+V
-V
L
LN
N
50/60Hz
AC100
-240V
Class2
Power
Supply
DC24V
2.5A
INPUT
OUTPUT
1.0A
+V-V
DCON
DCLOW
DCLOW
V.ADJ
+V
-V
L
LN
N
50/60Hz
AC100
-240V
Class2
Power
Supply
DC24V
2.5A
INPUT
OUTPUT
1.0A
+V-V
DCON
DCLOW
DCLOW
V.ADJ
+V
-V
L
LN
N
50/60Hz
AC100
-240V
Class2
Power
Supply
DC24V
2.5A
INPUT
OUTPUT
1.0A
+V-V
S8T-DCBU-02 S8T-DCBU-02 S8T-DCBU-02
Correct Correct Incorrect
DCON
DCLOW
DCLOW
V.ADJ
+V
-V
L
LN
N
50/60Hz
AC100
-240V
Class2
Power
Supply
DC24V
2.5A
INPUT
OUTPUT
1.0A
+V-V
DCON
DCLOW
DCLOW
V.ADJ
+V
-V
L
LN
N
50/60Hz
AC100
-240V
Class2
Power
Supply
DC24V
2.5A
INPUT
OUTPUT
1.0A
+V-V
S8TS-06024@S8TS-06024@
Selector

6Buffer Block S8T-DCBU-02
Inserting and Removing the Bus Line
Connector
Pay attention to the following points to maintain electric characteris-
tics.
•Do not insert and remove a Connector more than 20 times.
•Do not touch the Connector terminals.
•To remove a Connector, insert a flat-blade screwdriver alternately
at both ends.
Mounting to DIN Track
To mount the Block to DIN Track, hook portion (A) of the Block onto
the Track and press the Block in direction (B).
To dismount the Block, pull down portion (C) with a flat-blade screw-
driver and pull out the Block.
Checking Operation
After connecting the Blocks, check the Buffer Block using the follow-
ing procedure to confirm that it operates correctly for momentary
power failures on the AC input. Use this procedure for maintenance
as well.
1. Turn ON the AC power supply that has been connected.
2. Check the READY indicator on the S8T-DCBU-02 to confirm that
it is lit.
Note: Up to 60 seconds is required to charge the internal capacitor
before the indicator lights.
3. Use a timer and create a momentary power failure on the AC
input of the expected length of time. Considering variations in
characteristics, using 140% or more of the power failure time is
recommended.
Operation Check and Periodic Inspection
4. Check to confirm that the expected backup operation was per-
formed. The operation of the BACKUP indicator and BACKUP
output should be as shown below during the backup operation.
Check these as well.
Note: Check the backup operation under conditions that are safe and
will cause no problems if the backup operation fails.
B
A
30 mm min.
Track stopper
C
READY 1
2
READY output relayIndicator
Indicator lit
(READY: Green) Relay (READY) (1)-(2): open
H5CX-A
Digital Timer
E mode: Set for NPN input.
Load
6 7 8 9
11 12 13
10
1 2 3 4 5
SW
Not
used.
AC
Not
used. Not
used.
BACKUP 3
4
BACKUP output relayIndicator
Indicator lit
(BACKUP: Red) Relay (BACKUP) (3)-(4): closed

Buffer Block S8T-DCBU-02 7
■Functions
READY Operation
The READY indicator and READY output will function as shown
below after the internal capacitor is completely charged and the
Block is ready to perform the backup operation. Up to 60 seconds is
required for the capacitor to charge completely.
The following status will occur if there is an error in the charge volt-
age of the internal capacitor or the output voltage of the
S8T-DCBU-02.
The backup operation will not be sufficient or will fail under the above
status. If this status occurs, immediately remove the cause of the
error, such as the following causes.
1. The connected DC voltage is 23 V or less.
2. The terminals have been connected in reverse or wiring is other-
wise not correct.
3. The overvoltage protection circuit has operated.
4. The overcurrent protection circuit of the connected power supply
has operated.
Note: The contact capacity of the output relay is 0.1 A at 24 VDC.
Backup Operation
The S8T-DCBU-02 will switch to the backup operation if a voltage
drop is detected on the connected power supply.
When the backup operation functions, the energy in the internal
capacitor will be discharged to the load. When the voltage of the
power supply then recovers, the S8T-DCBU-02 will start charging the
capacitor. Up to 60 seconds is required to charge the capacitor com-
pletely. The backup operation may therefore not function for the
required period if the backup operation starts while the capacitor is
being charged.
The following are examples in which the backup operation may not
be sufficient.
1. The backup operation starts within 60 seconds after turning ON
the power supply.
2. The backup operation is started consecutively within 60 seconds
of the previous backup operation.
3. A rapid change in the load or other factor causes the DC voltage
to drop, resulting in the backup operation, and then the backup
operation occurs again within 60 seconds.
The READY indicator and READY output will function as shown
below when the internal capacitor is being charged.
Note: 1. The contact capacity of the output relay is 0.1 A at 24 VDC.
2. The backup operation may be repeatedly performed if the
connected power supply is overloaded. Remove the cause
of the overload immediately.
3. The backup operation does not detect drops in the AC input.
Overcurrent Protection
The overcurrent protection circuit will operate at an overcurrent
detection point of 5.8 to 6.8 A to automatically reduce the output volt-
age and protect equipment against shorts and overcurrents. Normal
operation will be restored automatically when the overcurrent status
is eliminated.
Note: Continuing operation in an overcurrent status may result in de-
terioration of or damage to internal parts.
Overvoltage Protection
If a voltage that is higher than the specified input voltage range is
input or the output voltage exceeds the specified voltage, the over-
voltage protection circuit will operate at between 31 and 36 V to shut
OFF the output voltage and protect the load from damage due to
overvoltages.
To restore operation, turn OFF the input power supply for 1 minute or
longer and then turn it back ON.
Note: 1. Remove the cause of the overvoltage before turn the input
power supply back ON.
2. The backup operation will not be performed when the over-
voltage circuit operates to shut OFF the output.
Reverse Connection Protection
The S8T-DCBU-02 will be protected even if the positive and negative
I/O terminals are connected in reverse.
READY
READY output relayIndicator
1
2
Indicator lit
(READY: Green) Relay (READY) (1)-(2): open
READY output relayIndicator
READY 1
2
Indicator not lit
(READY: Green) Relay (READY) (1)-(2): closed
BACKUP 3
4
BACKUP output relayIndicator
Indicator lit
(BACKUP: Red) Relay (BACKUP) (3)-(4): closed
READY output relayIndicator
READY 1
2
Indicator not lit
(READY: Green) Relay (READY) (1)-(2): closed

8Buffer Block S8T-DCBU-02
Nomenclature
Buffer Block
S8T-DCBU-02
A, B: READY Output: NC contact
C, D: BACKUP Output: NC contact
E: READY Indicator (READY: Green)
F: BACKUP Indicator (BACKUP: Red)
G: NC
H: Slider
I: Protective Earth Terminal
J: I/O Terminal (−V)
K: I/O Terminal (+V)
L: Rail Stopper
M: Connecting part of Bus Line Connector
N: Terminal Block Cover
Bus Line Connector
S8T-BUS-03
A: Selector
B: Ground Terminal
C: NC
D: DC Terminal (+V)
E: Bus Line DC Terminal (−V)
2
1
3
4
7
5
6
13
14
14
1110 9
12
8

Buffer Block S8T-DCBU-02 9
Engineering Data
■Characteristics
Derating Curve Note: 1. If natural air circulation is limited, use the forced air cooling
to prevent overheating.
2. The ambient temperature is measured at a point 50 mm be-
low the Buffer Block.
3. Check the derating curve for each power supply to be con-
nected. Refer to Connections to the S8TS (Reference Val-
ues) on page 11 for details on the derating curves when
connecting the Buffer Block to the S8TS-06024@Power
Supply.
Time Charts
Startup Momentary Power Failure or Voltage Drop
Power Supply Interrupted or Stopped
2.5
2.0
1.5
1.0
0.5
Current during backup operation (A)
Ambient temperature (°C)
−20 −100 1020304050607080
Charging
time
open
closed
open
closed
AC input
Internal capacitor voltage
I/O terminal voltage
READY output
BACKUP output
BACKUP indicator
Output current of the
S8T-DCBU-02
READY indicator
Power supply output hold time Power supply
restart time
AC input
Internal capacitor voltage
I/O terminal voltage
BACKUP indicator
Output current of the
S8T-DCBU-02
Backup time
open
closed
open
closed
READY output
BACKUP output
READY indicator
open
closed
open
closed
Backup time
2 seconds (typical)
AC input
Internal capacitor voltage
I/O terminal voltage
BACKUP indicator
Output current of the
S8T-DCBU-02
READY output
BACKUP output
READY indicator

10 Buffer Block S8T-DCBU-02
■Backup Time
Single Operation Parallel Operation with 2 Blocks
Parallel Operation with 3 Blocks Parallel Operation with 4 Blocks
Note: 1. The backup time may be reduced if a fixed power load (such as a DC-DC converter) is connected.
2. If the input voltage increases, the output voltage for the backup operation will also increase, reducing the backup time due to the higher
power consumption of the load.
10
1
0.1
Backup time (s)
Load current (A)
0.0 0.5 1.0 1.5 2.0 2.5
Vin = 24 V typical
Vin = 24 V guaranteed
Vin = 28 V typical
10
1
0.1
Backup time (s)
Load current (A)
0.0 1.0 2.0 3.0 4.0 5.0
Vin = 24 V typical
Vin = 24 V guaranteed
Backup time (s)
Load current (A)
10
1
0.1 0.0 1.5 3.0 4.5 6.0 7.5
Vin = 24 V typical
Vin = 24 V guaranteed
10
1
0.1
Backup time (s)
Load current (A)
0.0 2.0 4.0 6.0 8.0 10.0
Vin = 24 V typical
Vin = 24 V guaranteed