Contemporary Control Systems BAScontrol20 User Manual - Manual (Page 18)

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4.5 Universal Input
— Configured as Pulse Input
When an input is configured for Pulse Input, a pulse rate up to 40 Hz can be measured,
assuming a 50% duty cycle. The pulse device could have an active output or a
passive output requiring a pull-up resistor. Both situations can be accommodated.
The input voltage range is 0 –10 VDC and the installer can set both the low-threshold
and high-threshold on the Pulse Input web page. The difference in the two
thresholds is the hysteresis. You can detect a sinusoidal input by setting the high
threshold below the positive peak and the low threshold above the negative peak.
Setting both thresholds well away from the sinusoidal waveform peaks offers some
noise immunity. It is not necessary for the input to swing from zero to 10 V. Any
substantial swing within this range can be detected. The input impedance using
Pulse Input is 100 kΩ when using active sensors. Connect the output of the pulse
device to point A and the common to point C as shown in
Figure 7 .
If the pulse device has a passive output requiring a pull-up resistor, the BASC20 can
provide a 10 kΩ resistor to +12 VDC by checking a box on the configuration page.
The two threshold values can still be set as needed.
Figure 7 — Pulse Input Connections