32 in one strand

Switching safety switches in a series

You want to connect and monitor all safety switches on a machine? With safe series connection from SICK, this is possible for up to 32 devices: It’s quick, intuitive, and takes very little wiring effort.

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Transparent diagnostic data

No error masking with Flexi Loop

Thanks to the Flexi Loop diagnostic functions, errors in the safety functions can be reliably identified and displayed consistently and without error masking using the event history.

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Universal application

Flexi Loop and SICK safety controllers

You can combine Flexi Loop with all safety controllers from SICK. This enables use in both simple and complex applications that have to meet PL e requirements.

32 in one strand
Transparent diagnostic data
Universal application

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The flexible and safe series connection with diagnostic function
  • Safe series connection of up to 32 sensors regardless of the manufacturer
  • Up to 100 m in cable length between the sensors
  • IP65 and IP67 enclosure rating
  • Integration via M12 standard cable
  • Individual monitoring of the sensors up to PL e
  • Detailed diagnostic information
  • Direct voltage supply


Tailored to your requirements

The safe series connection from SICK impresses with its simple on site wiring and intuitive configuration with the Flexi Soft Designer or Safety Designer software. From individual machine modules to distributed machines: The safe series connection can be used on many different machines and delivers consistent information from all connected sensors.
In series with just a few clicks

Flexi Loop can be configured and commissioned using Flexi Soft Designer or Safety Designer software. Simply connect your sensors and configure them intuitively using the logic editor.

To the Flexi Soft Designer software

To the Safety Designer software

Wired with a single action Thanks to M12 plug connectors, you can use Flexi Loop to quickly connect safety sensors with OSSD outputs. No matter which sensors are used on your machines, Flexi Loop enormously reduces the wiring effort and the number of inputs required on the safety controller.

Clever combinations

The safe series connection is compatible with all safety controllers from SICK and can be adapted very well to your requirements. Thanks to the clever and compact product concept, you not only reduce the number of inputs on the controller, but you also benefit from the simple wiring. Combination of the machine modules is variable.
Intuitive configuration

Connect the safe series connection to programmable safety controllers from SICK. Commissioning is intuitive using the Flexi Soft Designer or Safety Designer configuration software. It also provides you with detailed diagnostic data on the status of your sensors.

Product recommendation Flexi Soft

Product recommendation Flexi Compact

Quick parameterization

The safety functions are set manually on the Flexi Classic safety controller using a rotary switch. The master node of the Flexi Loop then transmits all data of the sensors connected to the safe series connection to the Flexi Classic. Diagnostics are performed with the dedicated diagnostics node.

Product recommendation Flexi Classic

Easy connection

The special RLY3-LOOP100 safety relay monitors the sensors connected in series. You can adjust it using DIP switches. With the diagnostics node, all status information can be displayed at any time.

Product recommendation ReLy