Configuration - Spectris Particle Measuring Systems IsoAir 310P Operation Manual

Analog Inputs: Connections and Configuration

Configuration

When connecting the IsoAir 310P to Facility Net software, the Scale and Offset values
must be entered. Different Analog Output sensors can output values in current or
voltage, typically 4 – 20 mA or 0 – 10 volts. The Scale and Offsets must be calculated for
the specific operation (e.g. voltage or current), and these values are entered in the
Analog Input tab.
Range = the sensor's Maximum value – the sensor's Minimum value
Example: A Temperature sensor that measures from -32 to 120° F
Range = (120 – (-32)) = 152
Scale = (Maximum - Minimum) / (RawData Max - RawData Min)
where Maximum and Minimum is the working Range of the sensor
RawData Max and RawData Min is the range of current or voltage
The equation simplifies to:
Scale = (Sensor's Measurement Range) / (Sensor's Output Range)
Analog Sensors that Output Current: Most common is 4-20 mA operation, so in terms
of 4-20 mA electrical Current, the RawData Max is 20 and the RawData Min is 4.
Example: Using the temperature sensor above, the Range is 152.
Scale = (152) / (20 – 4) → (152) / (16) = 9.5
Analog Sensors that Output Voltage: In terms of voltage, the IsoAir 310P uses a 12-
bit Analog-to-Digital Converter (ADC). Consequently, if the Analog sensor operates on
differences in voltage—and not current—the Resolution must be considered.
The resolution (discrete voltage values) for a 12-bit ADC is 4096. The RawDataMax is
4095 and the RawDataMin is 0 (a discrete value).
Example: Using the previous temperature sensor, the Range is 152.
Scale: (152) / (4095 – 0) → (152) / (4095) = 0.037
IsoAir 310P Aerosol Particle Sensor Operations Manual
Chapter 6 4-20 mA Input and Solid State Outputs
Page 6-3