| • ALARM SIGNAL (Option ...A) The SEPA® MFB40H12XA includes a speed Impulse output, which enables monitoring the correct function of the fan. An alarm-board is available on request. The pulse Is like a rectangular wave. The pulse frequency correlates to 2 x rotor speed, OC-output, a pull-up-resistor is needed. At blocked rotor the output signal could be L (<0.5V) or H (Vcc). IMPORTANT: The pulse output is not protected against short circuit and must not connect to GND or Vcc without series-resistor. Do not connect not used pulse output to GND or Vcc (insulate) |