| • ALARM SIGNAL (Option) The SEPA® SFB25A05HA and the MFB25F12A include a pulse output, which allows monitoring the correct function of the fan. An alarm-board is available on request. SFB25A05HA: The pulse is like a rectangular wave, the frequency correlates to 4 x rotor speed. The amplitude is more than operating voltage and peaks up to 9 x operating voltage appear periodically. Please use a series resistor and a Z-diode to block up the high voltage. At blocked rotor the output signal could be L (<0.6V) or H (Vcc -1.5V). A pull-up-resistor is not needed. MFB25F12A: The pulse is like a rectangular wave, the frequency correlates to 2 x rotor speed. At blocked rotor the output signal could be L (<0.3V) or H (VCE -1.5V). A pull-up-resistor is needed. IMPORTANT: The pulse output is not protected against short circuit and must not connect to GND or Vcc without pre-resistor. Do not connect not used pulse output (insulate). Do not touch the rotor! |