Error position and fail-safe condition

Error position and fail-safe condition

GEMÜ valves are used in a variety of plants and they control various fluids and gases. But what happens in the event of an error – in the case of a power failure, an error in the control or a cable break? In these cases, the plants must be quickly placed in a safe state.

Protective mechanisms of the actuators

Error position

Actuators can detect errors, such as cable breaks or incorrect actuation signals, and initiate a defined error position for this case. To this end, the actuator must be supplied with power or compressed air without interruption.

Safety position

If the supply of electrical power or compressed air fails, the actuator detects the error and immediately moves to a fail-safe condition.

Pneumatic and magnetic actuators initiate the fail-safe condition via an internally installed spring.

Motorized linear actuators can only guarantee the fail-safe condition with internal or external emergency power supply modules.


More on electrical actuators

Emergency power supply modules for improving the plant reliability

For motorized actuators and for small quarter turn actuators, the fail-safe condition and, as a result, the safeguarding against power failures, is achieved using an emergency power supply module. The emergency power supply module is installed inside the actuator, on the actuator housing or in a control cabinet.


Electrical actuators with internal emergency power supply module

Pneumatic actuators have a fail-safe condition that cannot subsequently be changed due to the design. The motorized actuator GEMÜ eSyLite with integrated emergency power supply module can also not be reconfigured following delivery. The following actuators are available with an integrated emergency power supply module.

GEMÜ eSyLite

Actuator for Open/Close applications

  • Optical position indicator
  • Manual override
  • Emergency power supply module integrated as an option


Actuator for Open/Close applications

  • Operating condition displayed via a multi-coloured status LED
  • Integrated switching room heating
  • Electronic torque limitation
  • Handwheel for emergency operation and position indicator
  • Optional battery-powered safety pack


Motorized quarter turn actuators

  • Optical position indicator
  • Manual override
  • Emergency power supply module integrated as an option


Actuators in combination with an external emergency power supply module

To keep the space requirements as low as possible, the new drive series GEMÜ eSyStep and eSyDrive are delivered without an internal emergency power supply module. A flexible configuration with an external emergency power supply module is possible.

GEMÜ eSyStep

Universal actuator for open/closed and simple control applications     

  • Compact spindle actuator with stepper motor
  • I/O-Link interface for exchanging process, parametrization and diagnostics data
  • Wide range of adaptation options for add-on components and accessories

GEMÜ eSyDrive

Premium actuator for complex open/closed and dynamic control applications

  • Self-locking hollow shaft actuator with brushless and sensorless technology
  • Ideal for control applications thanks to its excellent positioning reproducibility
  • High actuating speed and long service life
  • Ethernet-based eSy-Web solution and Modbus TCP interface for exchanging process, parametrisation and diagnostics data

GEMÜ C53 iComLine

Demanding control applications in semiconductor production

  • High-resolution linear actuator with stepper motor
  • Tried and tested plug diaphragm design
  • Media-wetted parts made of PFA or PTFE
  • 1 million qualified control switching cycles
  • Cleanroom manufacturing (HP version), complies with SEMI F 57

External emergency power supply modules

For electrical actuators without an internal emergency power supply module, the GEMÜ 1571 external emergency power supply module can be used. It is clamped to the supply line, between the power supply unit and actuator.

A digital input of the actuator recognizes a failure of the power supply and places the valve in a defined safe state with the help of the emergency power supply module.

An additional memory module can be added to the emergency power supply module. Thanks to the expansion module, multiple actuators can be protected and failures can be bridged.


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