ctrlX Automation How-to FAQ

FAQ for ctrlX SAFETY

Community Manager
Community Manager
Which products are part of the ctrlX SAFETY solution?

A ctrlX SAFETY solution can be scaled from a drive-based solution to a multi-safety-controller solution. Thus it can consist of either a single ctrlX DRIVEplus with the SafeMotion option that includes a basic SafeLogic

  • or a combination of ctrlX SAFETY Safelogic controller combined with ctrlX DRIVE and its standard SafeTorqueOff function
  • or a combination of ctrlX SAFETY Safelogic controller combined with several ctrlX DRIVEplus and SafeMotion connected via ctrlX SAFETYlink or Safety over EtherCAT (FSoE)
  • or a combination of the aforementioned with several ctrlX SAFETY Safelogic controllers cross-communicating via FSoE-Master/Slave or Safe-Master-to-Master-Communication (SMMC).

How is the ctrlX DRIVE connected to the ctrlX SAFETY?

There are several connection or safe activation methods applicable between a ctrlX SAFETY Safelogic controller and a ctrlX DRIVE

  • ctrlX SAFETY can activate SafeTorqueOff on ctrlX DRIVE via local outputs
  • ctrlX SAFETY can activate any safety function on ctrlX DRIVEplus either using the ctrlX SAFETYlink or
  • Safety over EtherCAT (FSoE) communication.

What  is ctrlX SAFETYlink?

ctrlX SAFETYlink is the name of a proprietory safety bus, that connects a ctrlX SAFETY Safelogic controller Master with up to 16 ctrlX DRIVEplus SafeMotion Slaves to exchange safety-related signals and form a safety zone. Features to be emphasized are

  • faster activation compared to safe fieldbusses and shorter reaction time by a guaranteed bus cycle of 1 ms as well as
  • the fieldbus-independent connection between the Master (ctrlX SAFETY controller) and Slave devices (ctrlX DRIVEplus with SafeMotion).

Which safety protocols are supported by ctrlX SAFETY?

Thera are up to two interfaces to connect ctrlX SAFETY to fieldbusses:

  • At the moment the ctrlX SAFETY Safelogic controller supports safe fieldbus protocol Safety over EtherCAT (FSoE Master and Slave) on the primary Ethernet interface.
  • For the secondary Ethernet interface Profinet/ProfiSafe (Slave = Device) and EtherCAT/FSoE (Slave) is in preparation. EtherNet_IP/CIP Safety (Slave = Target) can be made available on request.

How many drives can be managed by ctrlX SAFETY?

One ctrlX SAFETY Safelogic controller is able to control safely

  • 32 ctrlX DRIVEplus as FSoE-devices via EtherCAT,
  • 16 ctrlX DRIVEplus via ctrlX SAFETYlink or
  • as many ctrlX DRIVE with SafeTorqueOff as free outputs are available.

What do I need in case of 40 axes for example?

It depends:

  • To control 40 axes via EtherCAT/FSoE, 2 ctrlX SAFETY Safelogic controllers attached to the same EtherCAT network do the job.
  • To control 40 axes via the much faster ctrlX SAFETYlink, 3 ctrlX SAFETY Safelogic controllers are needed.

Is it possible to have a safe communication between several ctrlX SAFETY controllers?

Several ctrlX SAFETY Safelogic controllers are able to cross-communicate safely

  • via FSoE-Master/Slave (up to 32+1 controllers) or
  • Safe-Master-to-Master-Communication (SMMC, up to 4 controllers).

Is it possible to expand the onboard safety IOs with expansion modules?

It is not possible to expand the onboard I/Os on the device directly. Due to the Safety-over-EtherCAT(FSoE)-Master functionality any FSoE-based I/Os can be used to expand the I/Os in total available.

Will Bosch Rexroth provide safety sensors and actuators?

Currently classical commanding and monitoring devices like emergency stop buttons, light curtains or safety scanners/radars are not part of the Bosch Rexroth safety equipment portfolio.

Whereas servo motors come with certified feedback systems for safe monitoring functions. In addition Bosch Rexroth’s business unit industrial hydraulics provides monitored valves and hydraulic control blocks for safety applications – e.g. for press technology.

Are there any safe I/O modules to extend the configuration of ctrlX SAFETY controllers?

Modular extensions are not stipulated in the current stage of the compact safety control ctrlX SAFETY.

  • To assure flexibility the ctrlX SAFETY controller is available in two configurations SAFEX-C.12 and SAFEX-C.15. They are equipped with diverse I/O periphery – for different complexity of applications.
  • Intelligent safety devices like safe I/O, light curtains or safety scanners and the ctrlX SAFETY controllers can be interlinked over the fieldbus and the safety-related protocol simply and directly.

Is it possible to interlink safety devices and ctrlX SAFETY controllers by radio?

Currently there are no safe radio devices part of the Bosch Rexroth portfolio.

Within the concept of an open system and open standards suitable senders and receivers, that are available on the market, can be combined with ctrlX SAFETY controllers.

Is there a high-level programming language to code safe applications with ctrlX SAFETY?

With textual high-level language programming the flexibility of the language implicates higher efforts, since the validation is extremely time-consuming, error-prone and inefficient for most of the users.

Application programs for safety controls have to be compliant to the relevant standards and easily verifiable, as the whole safety concept of a machine. In ctrlX SAFETY graphical programming (function block diagram) Bosch Rexroth is providing a tool, that comes with pre-certified function blocks and a way of free, validated and certified programming. That way the necessary steps to validate the whole safety system of a machine are strongly simplified.

How fast is the reaction of ctrlX SAFETY to safety relevant incidents?

The answer has to differentiate and depends on the signal path from sensor via ctrlX SAFETY Safelogic controller to the actuator:

  • The shortest reaction time is >=8ms, as fast as commercially available safety relays operate – however including the flexibility of a programmable control, if local I/Os are used. Here ctrlX SAFETYlink, the fast and safe connection to ctrlX DRIVEplus can be counted as local I/Os.
  • In case of safe fieldbus protocols being applied, the operation modes of the bus play a major role in determination of reaction time. In this context the necessary bus cycles from sensor to safe control and from safe control to the actuator need to be considered. The reaction time to be estimated – even with a bus cycle of 2 ms – is >=25ms in the best cases, partly considerably higher and depending on the fieldbus configuration.

Moreover it has to be distinguished between

  • a typical reaction time for the case of no transmission errors appear and mean values of consecutive, non synchronized cycle times (e.g. bus cycle vs. PLC cycle) are to be considered and
  • a maximum reaction time, that sums up all tolerated telegram failures and the most disadvantageous combination of consecutive cycle times in a timeout monitoring.


Where can I get Firmware and Device Description Files for SAFEX-C.1x from and how do I apply it?

ctrlX SAFETY SAFEX-C.1x firmware and device description files belong 1:1 together. Due to this fact the following rules and steps have to be followed:

  • Any released and certified package of firmware + device description files of SAFEX-C.1x controllers is provided in Bosch Rexroth’s Collaboration Room – subsection ctrlX SAFETY.
  • To download the firmware and device you need to register for a general ID for Bosch Web Services and ask your Bosch Rexroth contact to receive the specific access rights for the relevant Collaboration Room sections.
  • Once you got the ctrlX SAFETY access rights, log-in and navigate to SAFETY_Runtime_Apps->Runtime-Firmware and select the directory of the relevant firmware version:
    • Either you need just the Device Description files for the firmware installed on your device …
    • Or you want to update your device to an alternative firmware and download both – firmware and Device Description Files.
  • In case of a firmware update, please apply with your Bosch Rexroth contact for a KeyFile.
  • In case of Device description files only, please continue with the last step.
  • As soon as you have all described elements (Firmware + KeyFile + Device Description Files), please follow the description of the firmware update in the corresponding How-to article.
  • Please do not forget to update the device description files (according to the firmware version) inside the engineering software of your functional controller. This is valid
    • for the EtherCAT/FSoE connection on Ethernet interface 1 XF28/XF29 (for both SAFEX-C.12 and SAFEX-C.15) and
    • for the PROFInet/PROFIsafe connection on Ethernet interface 2 XF30/XF31 (only SAFEX-C.15).


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Hi, I am Katja a member of the ctrlX AUTOMATION Community team. Feel free to reach out if you need any support.
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