UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

BUFFER MODULE
 Buffering with electrolytic capacitors instead of lead acidbatteries Buffering of 24V loads
 Minimum hold-up time 0.2s at 20A, longer hold-up time at lower
loads
 Clear status indication by status LED and signaling terminals
 Quick-connect spring-clamp terminals
 3 Years warranty

PRODUCT DESCRIPTIONSHORT-FORM DATAThe UF20 buffer module is a supplementary device for regulated
DC 24V power supplies, which can be used for various purposes:- Deliver DC-power to bridge failures of the DC voltage
supply system.
- Extend the hold-up time after loss of the AC power.
- Deliver extra short-term peak current above the current
rating of the power supply.

Supply voltage
Required voltage tocharge capacitors
Threshold voltage forbuffer mode
Buffer voltage
Buffer current
Charging timeDC 24V -20%/+25%
typ. 23Vdc

19.2-30Vdc

22.5V / VIN-1V

Selectable

22.5V / VIN-1V
20A
typ. 25s
typ. 18s

Selectable

Current consumption

typ. 80mA
max. 600mA
1.9W
min. 200ms
min. 430ms
typ. 310ms
typ. 670ms
typ. 43s-25°C to +70°C
64x124x102mm
740g

It utilizes service-free electrolytic capacitors for storing theenergy which allows usage even at ambient temperatures up to+70°C.
The buffer module does not require any control wiring. It can be
added in parallel to the load circuit at any given point.
Buffer modules can be connected in parallel to increase theoutput ampacity or the hold-up time.

Power dissipation
Buffer time

Temperature range
Dimensions
WeightFor initial charging
For recharging
shortly after abuffer event
Stand-by mode
During charging
Stand-by mode
At 22.5V, 20A
At 22.5V, 10A
At 22.5V, 20A
At 22.5V, 10A
At 22.5V, 0.1A
Operational
WxHxD

ORDER NUMBERS

MAIN APPROVALS

Buffer ModuleUF20.241

For details and the complete approval list, see chapter 22.

Accessory

ZM1.WALL
ZM14.SIDE

Panel/ wall-mount bracket
Side-mount bracket
UL 508May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

UL 60950-1

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UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

INDEX
Page
1. Intended Use............................................................. 3
2. Installation Instruction............................................... 3
3. Functional Description............................................... 4
4. Electrical Ratings ....................................................... 5
5. Selection of the Back-up Threshold Voltage................ 6
6. Buffer Time ............................................................... 6
7. Charging Time ........................................................... 7
8. Operating Diagrams................................................... 7
9. Active Signal.............................................................. 8
10. Ready Signal.............................................................. 8
11. Inhibit Input .............................................................. 8
12. Efficiency and Power Losses....................................... 9
13. Lifetime Expectancy and MTBF .................................. 9
14. Functional Diagram ................................................. 10
15. Terminals and Wiring............................................... 10

Page
16. Front Side and User Elements.................................. 11
17. EMC........................................................................ 12
18. Environment ........................................................... 13
19. Protection Features................................................. 13
20. Safety Features ....................................................... 13
21. Dielectric Strength .................................................. 14
22. Approved, Fulfilled or Tested Standards................... 15
23. Regulatory Product Compliance............................... 16
24. Physical Dimensions and Weight.............................. 17
25. Accessories ............................................................. 18
25.1. ZM1.WALL - Wall mounting bracket ............... 18
25.2. ZM14.SIDE - Side Mounting Bracket ............... 19
26. Wiring Diagrams...................................................... 20

The information given in this document is correct to the best of our knowledge and experience at the time of publication. If not expressly agreed
otherwise, this information does not represent a warranty in the legal sense of the word. As the state of our knowledge and experience is constantly
changing, the information in this data sheet is subject to revision. We therefore kindly ask you to always use the latest issue of this document (available
under www.pulspower.com). No part of this document may be reproduced or utilized in any form without our prior permission in writing.
Some parts of this unit are patent by PULS (US patent No 091662,063, Des. 424,529, …).

TERMINOLOGY AND ABREVIATIONSPower supply mode

Describes a condition where the supply voltage is in the rated supply voltage range and the supplying
power supply can deliver a sufficient amount of current for the buffer module and the load. The mode canalso be called “Normal mode”.

Buffer mode

Describes a condition where the input voltage is below the transfer threshold level, the unit is running on
capacitors (buffering) and the output is loaded within the allowed limits.
The mode can also be called “Capacitor mode”.

Inhibit mode

Describes a condition where buffering is disabled on purpose (e.g. for service actions).

t.b.d.

To be defined, value or description will follow later.

DC 24VA figure displayed with the AC or DC before the value represents a nominal voltage with standard
tolerances included.
E.g.: DC 12V describes a 12V battery disregarding whether it is full (13.7V) or flat (10V).

24Vdc

A figure with the unit (Vdc) at the end is a momentary figure without any additional tolerances included.

may

A key word indicating flexibility of choice with no implied preference.

shall

A key word indicating a mandatory requirement.

shouldA key word indicating flexibility of choice with a strongly preferred implementation.

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

1. INTENDED USEThis device is designed for installation in an enclosure and is intended for commercial use, such as in industrial control, process control,
monitoring and measurement equipment or the like. Do not use this device in equipment where malfunction may cause severe personal
injury or threaten human life.

2. INSTALLATION INSTRUCTION
Risk of electrical shock, fire, personal injury or death.
- Turn power off before working on the device and protect against inadvertent re-powering.
- Do not open, modify or repair the device.
- Use caution to prevent any foreign objects from entering into the housing.
- Do not use in wet locations or in areas where moisture or condensation can be expected.
- Do not touch during power-on, and immediately after power-off. Hot surface may cause burns.
Obey the following installation instructions:This device may only be installed and put into operation by qualified personnel.
This device does not contain serviceable parts. The tripping of an internal fuse is caused by an internal defect.
If damage or malfunction should occur during installation or operation, immediately turn power off and send unit to the factory for
inspection.
Install the device in an enclosure providing protection against electrical, mechanical and fire hazards.
Install the device onto a DIN
rail according to EN 60715 with the power terminals on the top of the unit.
The device can be powered from a regulated power supply or a similar DC source. The voltage between the supply voltage terminals andthe PE terminal must not exceed 60Vdc continuously.
The device must be powered from a PELV or SELV source or an "Isolated Secondary Circuit" in order to maintain a SELV or PELV level.
Use an appropriately sized 24V power supply, which can deliver the additional internal current consumption, required to charge thecapacitors.
Check for correct supply voltage polarity. The device will not operate when the voltage is reversed.
Make sure that the wiring is correct by following all local and national codes. Use appropriate copper cables that are designed for aminimum operating temperature of +60°C for ambient temperatures up to +45°C, +75°C for ambient temperatures up to +60°C and+90°C for ambient temperatures up to +70°C. Ensure that all strands of a stranded wire enter the terminal connection.
The device is designed for pollution degree 2 areas in controlled environments. No condensation or frost is allowed. The enclosure of
the device provides a degree of protection of IP20.
The device is designed for convection cooling and does not require an external fan. Do not obstruct airflow and do not cover ventilation
grid!
Keep the following minimum installation clearances: 40mm on top, 20mm on the bottom, 0mm left and right side.
The device is designed for altitudes up to 6000m.
The maximum surrounding air temperature is +70°C. The operational temperature is the same as the ambient or surrounding air
temperature and is defined 2cm below the device.
The device is designed to operate in areas between 5% and 95% relative humidity.
For EMI reasons, signal lines (ready, active and inhibit) must be shorter than 30m

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

3/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

3. FUNCTIONAL DESCRIPTION
Working principle
When the power supply provides sufficient voltage, the buffer module stores energy in the integrated
electrolytic capacitors. In case of a voltage dip or loss, this energy is released to the DC bus in a
regulated process.
Bridges mains faults without interruption
Statistic show that 80% of all mains fault lasts less than 0.2s. These mains faults are completely bridged
by the buffer unit. This increases the reliability of the system as a whole.
Extended hold-up time
Once mains power fails or is switched off, the buffer unit will continue to provide the load current for adefined period of time. Process data can be saved and processes can be terminated before the DC
power switches off. Controlled restarts are subsequently possible.
Easy to handle, expandable and maintenance-free
The buffer module does not require any control wiring. It can be added parallel to the load circuit at
any given point. Buffer modules can be connected in parallel to increase the output ampacity or the
hold-up time.

Fig. 3-1 Typical wiring diagram

Load

-

-

optional+

BufferModule++N L PE

Storage

Discharge

AC
DC
Buffer Module
AC
DC
Buffer Module
Power
SupplyAC

BufferModule

Load

+
-

DC

Fig. 3-2 Transfer behavior

Power
SupplyOutputPower
SupplyChargeDC

Transfer ThresholdtSupplyVoltage
Power
SupplyMode

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

BufferMode

Power
SupplyMode t4/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

4. ELECTRICAL RATINGS
Supply voltage
Supply voltage range1)
Normal operating voltage range2)
Transfer voltage for switching into
buffer modenom.

Transfer voltage for switching from
buffer mode into power supply mode

typ.
typ.

Buffer voltage
Ripple and noise voltage- in buffer mode
- in power supply mode
Current consumption

typ.
max.

Power dissipation
Buffer current
Buffer current overload behavior
Allowed voltage between supply
voltage and chassis ground
Capacitive and inductive loads

DC 24V -20%/+25%
19.2 - 30Vdc
23 – 30Vdc
22.5Vdc
VIN – 1V

typ.
typ.
typ.

Back-up threshold jumper set to “22.5V fixed”
Back-up threshold jumper set to “VIN – 1V”
See also chapter 5.
22.5Vdc
Back-up threshold jumper set to “22.5V fixed”
VBUFFER + 1V
Back-up threshold jumper set to “VIN – 1V”
See also chapter 5.
Same as the transfer voltage for switching into buffer mode.
200mVpp
Generated by the buffer module.
Defined at 20Hz to 20MHz, 50Ohm
The ripple and noise voltage is defined by the power supply.
80mA
When capacitor is fully charged
400mA
During charging of the capacitors
600mA
During charging of the capacitors
1.9W
When capacitor is fully charged
20A
Electronically limited, buffering stops and capacitor gets discharged below 17V. See
Fig. 4-2.
60Vdc or 42.4Vac
Continuous, IEC 62477-1

typ.
min.
max.
typ.
min.

max.

No limitation

1) Supply Voltage Range:
At voltages within the input voltage range, control functions such as LEDs, monitoring features, relay contacts, etc. are functioning normally. Within the input
voltage range the unit can either be in power supply mode or in buffer mode.
2) Normal Operating Voltage Range:
The normal operating voltage range describes the supply voltage, which supports the full functionality of the buffer module (including charging) but without
entering the buffer mode.

Fig. 4-1 Selection of an appropriate power supply

Fig. 4-2 Output characteristic in buffer mode, 22.5V fixedmode, typ.

Buffer Voltage

28V
Power
SupplyCurrent

Load
Current

24

22.5V

20
16
12

Internal
current
consumption

Current
consumption
for charging

Buffering stops
below 17V

8
40

Output Current

0

4

8

12 16 20

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

24

28 32A

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UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

5. SELECTION OF THE BACK-UP THRESHOLD VOLTAGE
The buffer behavior can be selected with the back-up jumper selector between “Fixed Mode” and “Variable Mode”.
Fixed Mode: (Jumper in position „2-3“ or „22.5V fixed”)
If the supply output voltage falls below 22.5V, buffering starts and the supply voltage will be kept at this level.
This adjustment is recommended:- when power supplies other than the DIMENSION Q-series are used
- with back-feeding loads- when the buffer module is placed close to the load or- whenever in doubt.
Variable Mode: (Jumper in position „1-2“ or „VIN – 1V”)
Buffering starts if the supply voltage decreases by more than 1V. Buffering ends when supply voltage increases by more than 1V
Voltage changes slower than 0.54V/s will be ignored if the voltage is above 22.5V. Below 22.5V buffering starts immediately.
This adjustment is recommended for any application where 22.5V is too low for the application or when the buffer module is placed
close to the power supply.
The factory setting is fixed mode, A missing jumper means also fixed mode.

6. BUFFER TIME
The buffer time (sometimes also called autonomy time) is the maximum period of time for which the capacitor can maintain therequired output current. The buffer time mainly depends on the output current in buffer mode.
To increase the buffer time any given number of buffer modules can be connected in parallel.
Buffer time

min.
min.
typ.
typ.
typ.

200ms
430ms
310ms
670ms
43s

Fig. 6-1 Buffer time, typ.

At 22.5V, 20A
At 22.5V, 10A
At 22.5V, 20A
At 22.5V, 10A
At 22.5V, 0.1A
Fig. 6-2 Buffer time for small buffer currents, typ.

Buffer Current, typ.

Buffer Current, typ.

20A

2.0A

15

1.5

10

1.0

5

0.5
0

0
0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3s3

6

Buffer TimeMay 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

9

12

15

18s

Buffer Time

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UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

7. CHARGING TIME
Charging of the internal capacitors is indicated by the status LED, which is flashing with a slow frequency (1.25Hz).
Charging time

typ.
min.
max.
typ.
min.
max.

25s
20s
30s
23s
18s
28s

Initial charging 1)
Initial charging 1)
Initial charging 1)
Recharging 2)
Recharging 2)
Recharging 2)

1) Initial charging is the first charge after voltage is applied to the buffer module.
2) Recharging is the charging of the internal capacitors after voltage interruptions shorter than 2minutes.

Fig. 7-1 Recharging
Charge

mi n.

100%

typ.

max.

80
60

40
Recharging Time

20
0

5

10

15

20

25

30s

8. OPERATING DIAGRAMS
Fig. 8-1 Operating diagram
V MainsFig. 8-2 Signal schematic
Hold-up Time Power Supplyt

V Buffer
Capacitor

6 +t

7 Active

Vout

Ready

Optocoupler high ohmic

ActiveOptocoupler high ohmictOptocoupler
low ohmic

8 Readyt

5,1V

Optocoupler low ohmic
LED

1.25Hz

10Hz

t

3mA

UF20

9 InhibittCharging Mode

StandbyMode

Buffer Mode

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

7/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

9. ACTIVE SIGNALThe signal “Active” (pin 7) is an opto-coupler output which is low ohmic while buffer capacitors are discharged.
Wiring scheme see Fig. 8-2, Fig. 26-1 and Fig. 26-2.
Signal voltage
Signal current
Voltage drop across opto-coupler
Leakage current
Isolation voltage

max.
max.

35Vdc
10mA
0.9V / 3Vmax.
50µA
See chapter 21.

Voltage between pin 6 and 7
At 1mA / 5mA while opto-coupler is low ohmic
While opto-coupler is high ohmic

10.READY SIGNALThe signal “Ready” (pin 8) is an opto-coupler output which is low ohmic when buffer capacitors are fully charged.
Wiring scheme see Fig. 8-2, Fig. 26-1 and Fig. 26-2.
Signal voltage
Signal current
Voltage drop across opto-coupler
Leakage current
Isolation voltage

max.
max.

35Vdc
10mA
0.9V / 3Vmax.
50µA
See chapter 21.

Voltage between pin 6 and 8
At 1mA / 5mA while opto-coupler is low ohmic
While opto-coupler is high ohmic

11.INHIBIT INPUT
Buffering can be disabled or interrupted with the inhibit input (pin 9). Therefore, pin 6 should be connected to the positive pole of theterminal voltage or to the external control voltage and pin 9 must be connected to the corresponding negative pole.
Inhibiting the unit also discharges the internal capacitors. Charging of the capacitor is not possible when the buffer module is in inhibit
mode.
Wiring scheme see Fig. 8-2, Fig. 26-1 and Fig. 26-2.
Signal voltage
Signal current
Inhibit mode

max.
max.

35Vdc (between pin 6 and pin 9)
4mA, current limited

Isolation voltage

See chapter 21.

The unit does not buffer (or stops buffering) if the voltage between pin 6 and pin 9 is higher than
10V. Below 6V buffering will function again.

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

8/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

12.EFFICIENCY AND POWER LOSSES
Efficiency

typ.

>99%

Power losses

typ.

1.9W

Power supply mode, 20A output current,
capacitors fully charged
Power supply mode, 0A output current,
capacitors fully charged

13.LIFETIME EXPECTANCY AND MTBF
Calculated lifetime expectancy*)
MTBF**) SN 29500, IEC 61709
MTBF**) MIL HDBK 217F

166 000h*)
469 000h*)
2 327 000h
4 219 000h
398 000h
624 000h
132 000h
195 000h

Stand-by mode, 40°C
Stand-by mode, 25°C
Stand-by mode, 40°C
Stand-by mode, 25°C
Stand-by mode, 40°C, Ground Benign GB40
Stand-by mode, 25°C Ground Benign GB25
Stand-by mode, 40°C, Ground Fixed GF40
Stand-by mode, 25°C Ground Fixed GF25*)

The calculated lifetime expectancy shown in the table indicates the minimum operating hours (service life) and is determined by the lifetime expectancy ofthe built-in electrolytic capacitors. Lifetime expectancy is specified in operational hours and is calculated according to the capacitor’s manufacturer
specification. The manufacturer of the electrolytic capacitors only guarantees a maximum life of up to 15 years (131 400h). Any number exceeding this value
is a calculated theoretical lifetime which can be used to compare devices.
**) MTBF stands for Mean Time Between Failure, which is calculated according to statistical device failures, and indicates reliability of a device. It is the statisticalrepresentation of the likelihood of a unit to fail and does not necessarily represent the life of a product.
The MTBF figure is a statistical representation of the likelihood of a device to fail. A MTBF figure of e.g. 1 000 000h means that statistically one unit will failevery 100 hours if 10 000 units are installed in the field. However, it cannot be determined if the failed unit has been running for 50 000h or only for 100h.

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

9/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

14.FUNCTIONAL DIAGRAM
Fig. 14-1 Functional diagram+
Supply +Voltage-

StatusLED

Buffer Capacitor
Charger &Inrush Limiter
ReversePolarity
Protection

Safety and
OverVoltage
Protection

BufferCapacitor
Shut-Down

Buffer Capacitor
Discharger
BufferCapacitor

6 (+)
9 Inhibit

ChassisGroundOpto-coupler
Input / Output
Voltage Monitor

Back-up
Level
Selector+-

8 Ready
Opto-coupler

Ready Monitor+-

7 Active

Active Monitor Opto-coupler

15.TERMINALS AND WIRING
The terminals are IP20 finger safe constructed and suitable for field and factory wiring.

Type
Solid wire
Stranded wire
American Wire Gauge
max. wire diameter
Wire stripping length
Tightening torqueScrewdriver

Supply voltage, chassis ground
Quick-connect spring-clamp terminals
max. 6mm2
max. 4mm2
max. AWG 20-10
max. 2.8mm (including ferrules)
typ. 10mm
Not applicableNot applicable

Signals
Pluggable screw terminals
max. 2.5mm2
max. 2.5mm2
AWG 22-14
2.25mm (including ferrules)
6mm
0.4Nm
3mm slotted

Instructions:a) Use appropriate copper cables that are designed for minimum operating temperatures of:+60°C for ambient up to +45°C and+75°C for ambient up to +60°C and+90°C for ambient up to +70°C minimum.
b) Follow national installation codes and installation regulations!
c) Ensure that all strands of a stranded wire enter the terminal connection!
d) Unused terminal compartments should be securely tightened or closed.
e) Ferrules are allowed.

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

10/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

16.FRONT SIDE AND USER ELEMENTS
Fig. 16-1 Front side

A Supply Voltage Terminals
Quick-connect spring-clamp terminals, two per polarity+ Positive supply voltage terminal– Negative (return) supply voltage terminal
B

Chassis Ground Terminal
Quick-connect spring-clamp terminals
Connection of the chassis to ground (earth) is optional and only
required for a view specific applications.

C

Signal Connector
4-pole plug connector with screw terminal comprises the following
signals:- “Active” signal, for details see chapter 9.
- “Ready” signal, for details see chapter 10- “Inhibit” input, for details see chapter 11

D Status LED
This green LED indicates that the following information:- OFF: Capacitors are discharged or supply voltage isbelow 22V.
- ON: Capacitors are fully charged- Slow flashing (1.25Hz):
Capacitors are getting charged.
- Fast flashing (10Hz):
Capacitors are getting discharged.
E Back-up Threshold Jumper
Option 1: Fixed mode (Jumper in position 2-3)
The unit switches to buffer mode as soon as the voltage falls below 22.5V.
Option 2: Variable mode (Jumper in position 1-2)
Unit switches to buffer mode when input voltage decreases by 1V. Voltagechanges slower than 0.54V/s will be ignored if the voltage is above 22.5V.
Below 22.5V buffering starts immediately.
For more details see chapter 5.

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

11/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

17.EMCThe buffer module is suitable for applications in industrial environment as well as in residential, commercial and light industry
environment.
EMC Immunity
for all operating modes
Electrostatic discharge

According to generic standards: EN 61000-6-1 and EN 61000-6-2

Electromagnetic RF field
Fast transients (Burst)

EN 61000-4-3
EN 61000-4-4

Surge voltage on supply voltage
terminals
Surge voltage on inhibit input,
active signal and ready signal
Conducted disturbanceEN 61000-4-5

EN 61000-4-2

EN 61000-4-5

Contact discharge *)8kVCriterion A
Air discharge *)15kVCriterion A
80MHz-2.7GHz
10V/m
Criterion A
Input lines
2kV
Criterion A
Output lines
2kV
Criterion A
Signals lines pin 6, 7, 8, 9 **)2kV
Criterion A+0.5kV
Criterion A+ / -  chassis ground
1kV
Criterion A
Not applicable since length of signal wire specified shorter than 30m.

EN 61000-4-6

0.15-80MHz

10V

Criterion A*)
Chassis ground connection earthed (grounded)**) Tested with coupling clamp
Criterions:
A: Buffer module shows normal operation behavior within the defined limits.

EMC Emission
According to generic standards: EN 61000-6-3 and EN 61000-6-4
for standby- and charging
mode
Conducted emission,
IEC/CISPR 16-1-2, IEC/CISPR 16-2-1
Limits for DC power ports acc. EN 61000-6-3 fulfilled
supply voltage
Radiated emission
EN 55011, EN 55032
Class B
This device complies with FCC Part 15 rules.
Operation is subjected to following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept
any interference received, including interference that may cause undesired operation.

Switching Frequency

The buffer module has two converters with variable frequencies included.
6 to 610kHz
Charging converter at 24V input (is only active during charging)
The frequency depends on the state of charge of the capacitors
10 to 70kHz
Buffer converter at buffering at 22.5V
The frequency depends on the output current. The values are between 10%
and 100% of the nominal buffer current

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

18.ENVIRONMENT
Operational temperature *)Storage temperature
Humidity **)Vibration sinusoidal
Vibration random
Shock
AltitudeOver-voltage category
Degree of pollution-25°C to +70°C-40 to +70°C
5 to 95% r.H.
2-17.8Hz: ±1.6mm; 17.8-500Hz: 2g
2 hours / axis
0.5m²(s³)
2 hours / axis
30g 6ms, 20g 11ms
3 bumps / direction, 18 bumps in total
0 to 6000m
III
II
2

For storage and transportation
IEC 60068-2-30
IEC 60068-2-6
IEC 60068-2-64
IEC 60068-2-27
Approvals apply only up to 2000m
IEC 62103, EN 62477-1
IEC 62103, EN 62477-1, above 2000m altitude
IEC 62103, EN 62477-1, not conductive*)
Operational temperature is the same as the ambient or surrounding temperature and is defined as the air temperature 2cm below the unit.
**) Do not energize while condensation is present

19.PROTECTION FEATURES
Electrical protection
Over-voltage protection in buffer
mode
Degree of protection
Penetration protection
Reverse polarity protection
Input overvoltage protection
Internal input fuse

Electronically protected against overload, no-load and short-circuits
typ. 32Vdc
In case of an internal buffer module defect, a redundant circuit
max. 35Vdc
limits the maximum output voltage. Buffering stops andautomatically attempts to restart.
IP 20
EN/IEC 60529> 3.5mm
E.g. screws, small partsYesmax. -35V
Yes
max. 35V, no harm or defect of the unit
Not included

20.SAFETY FEATURESClass of protection

Isolation resistance

Chassis ground terminal resistanceNo classification according toIEC 61140 or IEC 60950-1
possible> 500MOhm> 500MOhm> 500MOhm< 0.1Ohm

Install the buffer module according to Class III rules

Supply voltage to signal port
Supply voltage to housing
Signal port to housing
Between housing and chassis ground terminal

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

21.DIELECTRIC STRENGTH
The signal port (active and ready signal and inhibit input) is floating and separated from the supply voltage.
Type and factory tests are conducted by the manufacturer. Field tests may be conducted in the field using the appropriate test
equipment which applies the voltage with a slow ramp (2s up and 2s down). Connect all poles of the power port terminals together aswell as all poles of the signal port before conducting the test. When testing, set the cut-off current settings to the value in the tablebelow. The following isolation tests were performed:
Type test

60s

A
500VacB
500VacC
500VacFactory test

5s

500Vac

500Vac

500VacField test

5s

500Vac

500Vac

500VacCut-off current setting

> 1mA

> 1mA

> 1mA

Fig. 21-1 Dielectric strength

SupplyVoltage

B

A

ChassisC

Active and Ready Signal
Inhibit Input

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

14/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

22.APPROVED, FULFILLED OR TESTED STANDARDSUL 508

IEC 60950-1

UL 60950-1

IEC 60068-2-60

ISA-71.04 G3

VDMA 24364

UL Certificate
Listed equipment for category NMTR - Industrial Control Equipment
Applicable for US and Canada
E-File: E198865
CB Scheme Certificate
General safety requirements for Information Technology Equipment (ITE)UL Certificate
Recognized component for category QQGQ - Information Technology
Equipment (ITE)
Applicable for US and Canada
E-File: E137006
Manufacturer's Declaration (Online Document)
Environmental Tests, Flowing Mixed Gas Corrosion Test
Test Ke - Method 4
H2S: 10ppb
NO2: 200ppb
Cl2: 10ppb
SO2: 200ppb
Test Duration: 3 weeks, which simulates a service life of a 10 years.
Manufacturer's Declaration (Online Document)
Airborne Contaminants Corrosion Test
Severity Level: G3 Harsh
H2S: 100ppb
NOx: 1250ppb
Cl2: 20ppb
SO2: 300ppb
Test Duration: 3 weeks, which simulates a service life 10 years
Paint Wetting Impairment Substances Test (or LABS-Test)
Tested for Zone 2 and test class C1 according to VDMA 24364-C1-L/W for
solvents and water-based paints

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

15/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

23.REGULATORY PRODUCT COMPLIANCE
EU Declaration of Conformity

REACH Regulation (EU)

WEEE Regulation

KC

UKCA

EAC

The CE mark indicates conformance with the- EMC directive- RoHS directive
Manufacturer's Declaration
EU regulation regarding the Registration, Evaluation, Authorisation andRestriction of Chemicals (REACH) fulfilled.
EU Regulation (EC) 1907/2006.
Manufacturer's Declaration
EU Regulation on Waste Electrical and Electronic Equipment
Registered as business to business (B2B) products.
EU Regulation 2012/19/EU
KC Korean Certification
Korean - Registration of Broadcasting and Communication Equipment
Registered under Clause3, Article 58-2 of Radio Waves Act.
Registration No. R-R-PUG-UF20_241.
UKCA Declaration of Conformity
Trade conformity assessment for England, Scotland and WalesThe UKCA mark indicates conformity with the UK Statutory
Instruments
2016 No.1091,
2012 No.3032
EAC Certificate
EAC EurAsian Conformity - Registration Russia, Kazakhstan and Belarus
8504408200, 8504409000

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

16/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

24.PHYSICAL DIMENSIONS AND WEIGHT
Width
HeightDepth

WeightDIN rail
Housing material
Installation clearances

64mm
124mm
102mm
The DIN rail depth must be added to the unit depth to calculate the total required installation
depth.
740g
Use 35mm DIN rails according to EN 60715 or EN 50022 with a height of 7.5 or 15mm.
Body: Aluminium alloy
Cover: Zinc-plated steel
See chapter 2
Fig. 24-1 Front viewFig. 24-2 Side view

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

17/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

25.ACCESSORIES

25.1. ZM1.WALL - WALL MOUNTING BRACKETThis bracket is used to mount the buffer module on a wall without utilizing a DIN rail.
The two aluminum brackets and the black plastic slider of the unit have to be detached, so that the steel
brackets can be mounted.

Fig. 25-1 Wall mounting

Fig. 25-2 Mounting Dimensions - Wall mounting bracket

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

18/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

25.2. ZM14.SIDE - SIDE MOUNTING BRACKETThis bracket is used to mount the buffer module sideways with or without utilizing a DIN rail.
The two aluminum brackets and the black plastic slider of the unit have to be detached, so that the steel
brackets can be mounted.
For sideway DIN rail mounting, the removed aluminum brackets and the black plastic slider need to be mounted
on the steel bracket.

Fig. 25-3
Side mounting without DIN rail
brackets

Fig. 25-4
Side mounting with DIN rail
brackets

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

Fig. 25-5
Mounting Dimensions
Side mounting bracket

19/20

UF20.241
24V, 20A, 200MS, BUFFER MODULE

UF-Series

26.WIRING DIAGRAMS

L
N
PE

optional++ - -+- +-IN 1 IN 2

Adj
DC-OK
Overload

InhibitExt ernal
Volt age Source

Ready
Relay, lamp or signal
Statusoptional

May 2023 / Rev. 2.1 DS-UF20.241-EN
All parameters are specified at 24V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

OUT

+ -

+Buffered
Load

6 +

L N PE

UF20
Back-up
Buffer Thres
hold
Module7 Act ive

YR2
Redundancy
ModulePower
SupplyL
NPE- - ++

8 Ready+Unbuffered
Load

6 +

7 Act ive

8 Ready

UF20
Back-up
Buffer Thres
hold
Module9 Inhibit

6 +L N PE

7 Act ivePower
SupplyL
N
PE

Status8 ReadyLoad- - ++

Status

UF20
Back-up
Buffer Thres
hold
Moduleoptional

Fig. 26-4 Decoupling of buffered branches- - ++

9 Inhibit+-

Act ive
Relay, lamp or signal

L N PE

Fig. 26-3 Paralleling of buffer modules

Adj
DC-OK
Overload

UF20
Back-up
Buffer Thres
hold
ModulePower
Supply+optional++ - -

Status

6 +Inhibit

Ready
Relay, lamp or signal

Act ive
Relay, lamp or signal

Load

-

- - ++Adj
DC-OK
Overload+-

9 Inhibit

L
N
PE

6 +

9 Inhibit

L N PE

7 Act ive

UF20
Back-up
Buffer Thres
hold
ModulePower
Supply8 ReadyLoad++ - -

Status

7 Act ive

- - ++Adj
DC-OK
Overload

9 Inhibit++ - +-

Fig. 26-2 Signals supplied from an external voltage source

8 ReadyFig. 26-1 General wiring diagram

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