| • ALARM SIGNAL (Option ...A) The SEPA® MFB40X12XA 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, Open-Collector-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 (insolate). |