Parker Vansco VMM1210, Руководство пользователя

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16 VMM1210
Inputs
3.3.1.1. Analog Input Capabilities
The following table provides specifications for the VMM1210 analog inputs:
Analog Input Specifications
Item Min Nom Max Unit
Input voltage range 0 - 32 V
Overvoltage (5 minutes) - - 36 V
Pull-up resistance 3.1 - 3.5
kΩ
Analog internal range (see note) - 4.096 - mV
Analog gain 1 - 6.029 V/V
Analog attenuation .1282 - 1.0 V
Input pin capacitance - .01 - µF
Note: For analog internal range, ensure that you attenuate or boost an analog input signal
such that you maximize the internal range to ensure the highest resolution possible on the
analog reading. For example, an analog input signal with a maximum value of 13.38V should
be attenuated with 0.3061 which gives the analog input an internal range from 0 to 4.096.
3.3.1.2. Analog Input Configuration Options
If one of the VMM1210’s multi-purpose inputs is configured as an analog input,
the input will be converted by the microprocessor using a 10-bit analog to digital
converter (ADC).
Analog inputs allow an analog input voltage of 0 to 32 V. The inputs have
programmable gain values (1, 3.007, 4.022, 6.029), and programmable attenuation
values (1, 0.3061, 0.1807, 0.1282).
The gain values and attenuation values can be mixed and matched to produce
other gains/attenuation factors. The maximum internal voltage range is from 0 V
to 4.096 V, so the maximum external voltage should produce an internal voltage
of no greater than 4.096. If it does, the analog input will clamp at maximum
value. Attenuations/gains should be selected to allow the external analog input to
be mapped into the internal voltage range to maximize analog input resolution.
Analog readings by the module can be used in ladder logic as either voltage
readings with resolution of 0.1 V or as “raw” AD Converter 10 bit values with
resolution down to 1 bit (or 0.004 V). The 1 bit resolution does not include initial
error inherent in the AD Converter and the amplifier input. Additional error can
result from long cable runs or mismatched grounds from sensor to module.
Note: If any of the inputs INPUT9_ADF to INPUT12_ADF are left floating
and are programmed as analog inputs, they may read non-zero values in
ladder logic. To avoid this, either connect the floating pin to a grounded
resistor externally, or add some attenuation in ladder logic. Attenuation factors
added in ladder logic will add internal pull-down resistors on the input in
question.