Vansco VMM3120, User Manual

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24 VMM3120
Inputs
3.3.2. DC-Coupled Frequency Inputs
The VMM3120 has 2 DC-coupled frequency inputs:

FREQ_3

FREQ_4
3.3.2.1. DC-Coupled Frequency Input Capabilities
DC-coupled frequency inputs allow you to read the frequency of external signals
that have a ground reference and no DC offset. These inputs are ideal for use with
hall-effect type sensors.
Note: Quadrature and pulse counting is possible with DC-coupled frequency
inputs.
The following table provides specifications for the VMM3120's DC-coupled
frequency inputs:
DC-Coupled Frequency Input Specifications
Item MIN NOM MAX UNIT
Input voltage range 0 - 32 V
Pull-up resistance power dissipation - 0.125 0.25 W
Pull-up resistance 4.7 k - -
Ω
Overvoltage - - 36 V
Frequency accuracy - - 5 %
Frequency range 1 - 10000 Hz
Minimum negative going threshold 1.56 - - V
Maximum positive going threshold - - 3.65 V
Analog gain - - 1 V/V
Analog resolution - 10 - Bit
Analog accuracy - - 3 %
ADC reference voltage 2.994 3.0 3.006 V