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.  

Download the white paper on efficient power supply concepts with NEC Class 2:

Access the white paper

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  48 V and 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.

  • Reliable tripping, regardless of the cable lengths or cable cross-sections
  • 4 or 8 24-V DC load feeders per module
  • 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
  • SEL1200/1400: 4 or 8 outputs, each with diagnostics of voltage, current, set threshold, reason for disconnection (if applicable)
  • PSE200U: 4 outputs with voltage measuring point for current (1 V ≙ 1 A)
  • 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

Reliable system protection against a wide variety of potential hazards

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 and RED1200 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 failure safety. If one unit

fails, the other automatically takes over the power supply

function. Even in the event of a short circuit inside a power

supply unit, the power supply remains reliable. Thanks to

its high dielectric strength, the new RED1200 redundancy

module also decouples power supplies without output

voltages up to 48 V.

Your benefits with a SITOP redundancy module

  • Highly secure DC supply thanks to a redundant design
  • Reliable supply even when one power supply fails
  • Compact redundancy modules for power supply units up to 48 V and 40 A 
  •  24-V/NEC Class 2 redundancy module limited to 100 VA
  • Decoupling of parallel-connected power supply units to enhance performance or of series-connected power supply units to increase voltage
Application note: “Secure 24-V DC even when a power supply unit fails”

Open the Application Note

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

The SITOP selectivity modules are specifically tailored to switched-mode power supplies. The modules permit brief current peaks and switch off the electricity for longer overloads, even on long, thin cables and with creeping short circuits in which the current is limited by the high ohmic  resistance. In this case the circuit-breakers do not trip, or they trip too late, even if the power supply could deliver the current. The selectivity modules reliably disconnect the faulty load circuits, and the supply to the other loads continues with absolutely no interruption so that total failure of the plant can be avoided. The affected feeder is indicated by an LED. The option with single-channel signaling also allows remote output-specific fault location. The new SEL1200 and SEL1400 eight-channel modules also have an interface with comprehensive diagnostics options for each output.

Your benefits with a SITOP selectivity module

  • Protection against overloads and short circuits in the 24-V circuit
  • Reliable tripping, regardless of the line resistance
  • SEL1200: switch-off characteristic for standard protection and high starting currents
  • SEL1400/PSE200U: power limiting to meet high protection requirements by stabilizing the 24 V
  • Sequential connection reduces total inrush current
  • Common signaling contact or evaluation of individual channels
  • SEL1200/1400: 8 outputs, each with diagnostics of voltage, current, set threshold, reason for disconnection (if applicable)
  • PSE200U: 4 outputs with voltage measuring point for current (1 V ≙ 1 A)
Brochure: Electronic protection and fast fault localization in 24 V DC load circuits

Open the brochure

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

Everything you need to know about SITOP add-on modules

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.

The fastest path to the experts

Proposed solutions for your queries and direct access to our experts in Technical Support

Special investigation

Special investigations analyze the causes of problems that have been occurring more frequently with no explanation.

Logistical handling of returned goods from service processes

Central returns processing at the Service Logistics Center in Erlangen

Return delivery address: Siemens AG Retouren Center c/o Geis Industrie-Service GmbH, Tor 1–4, Kraftwerkstrasse 25a, 91056 Erlangen

Contact

SITOP – The heart of automation® 

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.

Would you like to know more?

Contact us