Redundant pulse evaluation system for safe standstill monitoring
Standstill safely detected!
- Rotational speed detection by 2 sensors.
- Redundant structure of the hardware.
- Redundant evaluation of the pulse sequences.
- Relay with positively-driven contacts.
- 4 switch points selectable.
Operating principle
The standstill monitor is a pulse evaluation system for safe detection of underspeed or standstill. It receives the pulses from the pulse pick-ups connected on the inputs.
The µPs calculate the pulse sequence time and the resulting frequency according to the principle of interval measurement. By continuously comparing the input frequency (actual value) and the switch point (preset value) the evaluation system promptly detects standstill and the output relays switch according to the preset switching function.
Switching function
In accordance with "safe" standstill signalling, the relays are energised when the event occurs. The relays switch when the actual value falls below the activated preset value by e.g. 5%. The NO contacts of the relays are connected in "series" and connected to the terminals.
