Safety relay with time-delayed output
AZS series SCHMERSAL

The AZS fail-safe delay timer serves for the secure measurement of a preset time. The enabling signal for the control system, which for example makes it possible to open a guard device, is only given when the present time has elapsed. AZS range fail-safe delay timers are often used where dangerous situation can occur after a machine or plant has been switched off, e.g. because of running-down movements. Depending on the external circuit arrangements, the protection system can be secured up to the requirements of Control Category 3 to EN 954-1 in combination with an AES or AZR range safety monitoring module.

Design and mode of operation:
The saftey monitoring module is designed with two redundant channels. In each channel there is a microprocessor with coding switches for the time setting and a safety relay. The enabling paths each comprise one NO contact of each of the two safety relays wired in series. The two additional transistor outputs are short-circuit proof and can be used for indication purposes.

When the power contactors drop out, the inputs of the timer are activated and the set time begins. When this time has elapsed, the enable signal is given and coil of the AZM range solenoid interlock is energised. The guard device can be opened.

The AZS range fail-safe delay timer is equipped with Integral System Diagnostics (ISD) for fast and simple recognition of faults.

The fail-safe delay timers are available for various operating voltages.