SITOP add-on modules – all-round protection à la carte

Product line picture of the SITOP add-on modules

Expansion modules for increasing system availability up to total all-round protection

The quality of the power supply unit alone can’t guarantee a fault-free, 24-V supply. Power failures, extreme variations in the mains voltage or a faulty load can bring plant operation to a standstill and cause high costs. That’s why processes and plants that are critical for a company’s business generally require additional protection measures. SITOP add-on modules protect your production from a wide variety of potential hazards on the primary and secondary side and allow the completely flexible expansion of SITOP power supply units up to total, all-round protection.  

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Product image of an exemplary SITOP redundancy module

SITOP redundancy modules

SITOP redundancy modules

High availability of the 24-V supply thanks to redundant configuration 

Two power supply units can be connected via a SITOP redundancy module for additional protection against failures. If one power supply fails, the other automatically takes over the power supply function. That’s how SITOP safeguards the power supply in unstable conditions.

 

  • Power is reliably supplied even when one power supply fails
  • Compact redundancy modules for power supply units up to 40 A
  • Redundancy module SITOP PSE202U, 24 V/NEC Class 2 limited to 100 VA
  • For SITOP PSE202U, diagnostics signal via LED and signaling contacts, and adjustable switching threshold for LEDs and signaling contacts
Product image of an exemplary SITOP selectivity module

SITOP selectivity modules

SITOP selectivity modules

Selectivity and fast fault location in 24-V DC load circuits 

The SITOP selectivity and diagnostics modules are the optimal extension for all 24-V DC power supplies. They distribute and monitor the load current over several current circuits. Overloads and short circuits on a circuit are reliably recognized and the faulty 24-V DC load circuit reliably disconnected, while the other loads continue with absolutely no interruption; this prevents the complete failure of the plant.

 

  • Protection ageinst overloads and short circuits in the 24-V DC circuit
  • Reliable tripping, regardless of the cable lengths or cable cross-sections
  • 4 or 8 24-V DC load feeders per module
  • Available in versions with an adjustable output current range  of 0.5 to 3 A , 2 to 10 A and 3 to 10 A, as well as variants with power limitation for the outputs to 100 VA according to NEC Class 2 Sequential connection delay of individual 24-V DC load circuits reduces inrush current
  • Alternative switch-off characteristics:
    - Limiting – prevents short-term voltage drop to below 20 V 
    - Switching – can result in short-term voltage drop to below 20 V
  • Diagnostics via common signaling contact or single channel signaling
  • Evaluation by free SIMATIC S7 function blocks for modules with single-channel signaling

 

Product image of a SITOP buffer module

SITOP buffer modules

SITOP PSE201U buffer modules

Bridging short-term power failures

Power failures usually last only a fraction of a second – but they can cause time- and cost-intensive damage. Used in combination with the 24-V DC power supply units from the SITOP smart and SITOP PSU8200 product lines, the buffer module bridges short-duration voltage dips with its electrolytic capacitors and reliably preserves interruption-free operation.

 

  • Fast and easy DIN rail mounting
  • Connects to the basic module with only two lines
  • Protection against short power failures
  • Buffering time 100 ms to maximum 10 s, depending on load current
  • Multiplication possible using parallel switching
  • Longer power failures bridged by the DC UPS for up to several hours
Product image of a SITOP inrush current limiter

SITOP inrush current limiters

SITOP inrush current limiters

Protection for your loads

As a ballast unit for SITOP power supplies, SITOP inrush current limiters reliably reduce inrush currents like those caused by the rectifier circuit on the input side with capacitor charging – as in the case of pulse-controlled power supplies. An inrush current limiter can also significantly extend the service life of the connected loads.

 

  • Maximum service life of current-sensitive components like relays thanks to reduced current inrushes
  • Space-saving, thanks to narrow width of only 18 mm
  • Suitable for LOGO! modules and sub-distribution boards thanks to stepped profile
  • Flexible installation on the DIN rail, on the wall or in various other locations
  • Maximum plant configuration enabled
  • Flexible application options at temperatures ranging from -40° Celsius to +70° Celsius
All-round protection

You can ignore risks – or play it safe.

Power failures, extreme variations in the mains voltage or a faulty load can bring plant operation to a standstill and cause high costs. That’s why SITOP offers you a unique range of perfectly integrable expansion modules for reliable protection against a wide variety of potential hazards on the primary and secondary side. The SITOP add-on modules allow the completely flexible expansion of SITOP power supply units and extension up to total, all-round protection.

Protect yourself against …

Safeguarding against failure through redundancy – with SITOP redundancy modules

Because two power supplies are decoupled via a SITOP redundancy module, the failure of one power supply unit has no effect on the 24-V DC supply. The SITOP redundancy module continuously monitors the feeding power supply units. In addition, the SITOP PSE202U redundancy modules send a signal via a signaling contact that can be evaluated by a controller, PC, or control system.

A redundant design for greater reliability

Two power supply units can be connected via the SITOP redundancy module for additional resistance to failure. If one unit fails, the other automatically takes over the power supply function. That’s how SITOP safeguards the power supply in unstable conditions.

It isn’t enough to switch the power supply units in parallel. If the defect is on the secondary side and causes a short circuit on the 24-V side, the intact power supply would also feed into the short-circuited electrical circuit and interrupt its own 24-V supply. With decoupling, the intact power supply isn’t affected by the short circuit and power is still supplied.

Your benefits with a SITOP redundancy module

  • Highly secure 24-V DC supply thanks to a redundant design
  • Reliable supply when one power supply fails – even with a short-circuit in the defective power supply unit
  • Compact redundancy modules for power supply units up to 40 A
  • 24-V DC/NEC Class 2 redundancy module limited to 100 W
  • SITOP PSE202U with diagnostics signals via LEDs and signaling contacts
  • Adjustable switching threshold for LEDs and signaling contacts with
    SITOP PSE2020 U
Application note: “Secure 24-V DC even when a power supply unit fails”

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Selectivity and fast fault location in 24-V DC load circuits – with SITOP selectivity modules

In modern plant and machine construction, all 24-V DC loads – whether rugged electromechanical loads or highly sensitive electronics – are supplied by a single, common, stabilized, switched-mode power supply. To ensure that a fault in one load doesn’t bring the complete plant to a halt, the 24-V DC power supply circuit is divided into separate branches and selectively protected.

Selective monitoring of 24-V DC load circuits instead of protection via miniature circuit breakers

SITOP selectivity and diagnostics modules are the optimal extension for all 24-V DC power supplies. They distribute and monitor the load current over several current circuits. Overloads and short circuits on a circuit are reliably recognized.

SITOP selectivity modules are specifically designed for switched-mode power supplies. They permit brief current peaks and switch longer overloads off-circuit, even on long, thin cables and with ground leaks where the current is limited by high resistance. In this case, the circuit breakers either fail to trip or trip too late, even if the power supply could deliver the current.

The selectivity module reliably disconnects the faulty load circuit and the supply to the other loads continues with absolutely no interruption – which prevents the total failure of the plant. The load circuit affected is indicated by an LED. The version with single-channel signaling also permits remote, channel-specific fault localization. 

Your benefits with a SITOP selectivity module

  • Easy configuration using individual setting of the maximum current via potentiometer for each channel
  • Two options for remote diagnostics: common signaling contact or single-channel signalling
  • Evaluation via free SIMATIC S7 function blocks (S7-1500/1200/300/400) for modules with single-channel signalling
  • Library for visualization in SIMATIC PCS 7
  • LEDs for fast fault location on site
  • Remote reset possible from centralized location
  • Easy commissioning using manual on/off switching of channels with reset button
  • Voltage measuring points for output current  (1 V = 1 A), no separation of the circuits required
  • Sequential connection delay of individual 24-V DC load circuits reduces the total inrush current
  • Sealable transparent cover protects against maladjustment of tripping current and sequential delay
Application note: “Monitoring 24-V DC load circuits”

Open the Application Note

Bridging short-term power failures – with the SITOP buffer module

In sensitive production areas, short-term power failures (brownouts) can have time- and cost-intensive consequences, even if they only last for a fraction of a second. The SITOP buffer module permits reliable bridging for up to ten seconds and so ensures reliable, interruption-free operation.

Bridge power failures for a period of seconds

Power failures usually last only a fraction of a second – but they can cause time- and cost-intensive damage. Used in conjunction with SITOP modular power supply units, the buffer module bridges short-duration voltage dips with its electrolytic capacitors.

Power failures can easily be bridged for up to ten seconds, depending on the charging current and the number of buffer modules.

Your benefits with the SITOP buffer module

  • Economical protection against power failure for a maximum of ten seconds
  • Support for the power supply unit when the power demand temporarily increases
  • High load current up to 40 A
  • Only two lines connecting to the power supply unit

And for buffering longer power failures …

Reliable reduction of inrush currents – with SITOP inrush current limiters

High inrush currents from starting motors, transformers, converters, and other equipment can trip protective devices, increase wear and tear or even damage sensitive components. In these cases, SITOP inrush current limiters ensure protection of the power supply and all connected loads.

Your benefits with the SITOP inrush current limiters

  • Maximum service life of current-sensitive components like relays thanks to reduced current inrushes
  • Space-saving, thanks to narrow width of only 18 mm
  • Suitable for LOGO! modules and sub-distribution boards, thanks to its stepped profile
  • Flexible installation on the DIN rail, on the wall or in various other locations
  • Maximum plant configuration enabled
  • Flexible application options at temperatures ranging from -40° Celsius to +70° Celsius
Downloads, support, services

You can make a note of the information. Or download it.

Download brochures and documentation with more details on all-round protection with SITOP add-on modules. Support links take you to system-specific FAQs, manuals, product notes, and technical data. Discover our range of helpful services at the same time.

Contact

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If you’d like to know even more about our SITOP add-on modules for the all-round protection of your 24-V DC power supply, or if you have any questions, just talk to our experts. They’ll be happy to assist you.

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