Safety relays can be used in a variety of ways. They perform monitoring tasks in safety applications in combination with different non-contact guards. They are capable of evaluating signals from safety light grids, safety light curtains, position sensors with and without cross-fault monitoring, electronic safety sensors or mechanical safety switches for protective guard contacts. The safety relay has several multifunctional self-detecting and self-monitoring short-circuit protected inputs and outputs. The simultaneity monitoring of inputs and the functions "monitored" or "automatic start" can be set as an option. The operation in two-hand control to EN 574 type IIIC in combination with electronic sensors or mechanical switches is another advantage of the safety relay.

Safety relays with relay outputs are used for the connection of safety light curtains and grids. Muting function as well as signal and feedback contacts are integrated. Muting is the temporary suspension of the protective function of safety light curtains / light grids to transport objects through a hazardous area as planned.
In handling and loading stations, the muting function reliably differentiates between the entry of personnel and material.

ifm Safe standstill monitoring

• Speed detection through pulse comparison of two sensors
• Redundant structure of the hardware
• Redundant evaluation of the pulse sequences
• Relay with positively-driven contacts
• Four switch points selectable

		Product designation	Dimensions	Operating voltage DC	Electrical design	Protection
	DA102S	Safety standstill monitor for underspeed detection	100 x 25 x 105 mm	–	–	IP 20

The DA standstill monitor is a pulse evaluation system for safe detection of underspeed or standstill. It receives the pulses from the sensors connected on the inputs as pulse pick-ups and calculates the frequency. By continuously comparing the input frequency (actual value) and the switch point (preset value), the unit promptly detects underspeed or standstill.
For example, the standstill monitor can be used on a rotating machine part such as a drive, motor or shaft to determine whether it has been brought to a standstill due to a braking action. Any damage to persons or installations is reliably prevented.

The DD110S and DD111S speed monitors are designed for safety-related maximum speed monitoring. Typical applications include carousels or centrifuges. The DD111S is specially designed for the low rotational speed of wind turbines.
Both speed monitors can also be used for the operating mode "reduced speed" e.g. on machine tools.
The speed monitors are certified to EN 62061 / SIL 3 and EN ISO 13849-1 cat. 4 / PL e, even if non-safety-related standard sensors are used as pulse pick-ups.
When the safety output has been triggered, it can be reset again manually or automatically.

ifm Safe monitoring of underspeed

• Easy parameter setting via rotary switch
• Use of a large variety of cam discs
• Monitoring functions can be switched on and off
• Reliable operation at extreme ambient temperatures down to -40 °C
• Slim housing
  
  

Applicable products: 1

		Product designation	Dimensions	Operating voltage DC	Electrical design	Protection
	DU110S	Safe speed monitor for underspeed detection	108 x 22.5 x 114.5 mm	–	–	IP 20

The speed monitor of the DU series has been developed for safety-related minimum speed monitoring. It receives the pulses from the sensors connected on the inputs as pulse pick-ups and calculates the frequency. By continuously comparing the input frequency (actual value) and the switch point (preset value), the unit promptly detects underspeed.
The minimum speed is easily set via rotary switches.
In addition to the safety relays, transistor outputs are available for status and error indication.
The monitors are widely used on fans of industrial furnaces or paint shops in the automotive industry.