Page 4-6
IsoAir 310P Aerosol Particle Sensor Operations Manual
Chapter 4 Facility Net Setup
Configuring Analog Input (Optional)
Analog Sensors Tab Field Definitions
Name
Allows the user to select a meaningful name for the analog data.
An example for Analog Input 1 is DAP.
Type
Each IsoAir 310P particle sensor instrument has a sensor-type
associated, which is displayed in the “Type” field (non-editable).
The type defines the flow rate, number of channels, and channel
sizes that are downloaded from the sensor.
Units
A text field used to identify the units of the scaled data in Facility
Net. It is used for display only and has no effect on the actual
scaling of the data.
Scale and Offset
The value reported by the IsoAir 310P particle sensor to Facility Net
is the actual current flowing into the sensor’s analog input
terminal. For a correctly operating sensor, this will be between 4
and 20. To produce the scaled value that will be saved and
displayed by Facility Net, this value is multiplied by the number
entered into the scale field and then added to the number entered
into the offset field. For a differential pressure with a full scale
reading of 0.1 inches of water, the correct values to produce a
reading between 0 and 0.1 are: Scale = 0.00625 and Offset = -0.025.
OK
Clicking the
OK
button accepts the changes to the settings and
closes the dialog box.
Cancel
Clicking the
Cancel
button ignores the changes to the settings (if
any) and closes the dialog box.
Help
Clicking the
Help
button invokes context-sensitive help.
Configuring Analog Input (Optional)
Three analog (4-20 mA) user inputs are available. Data is reported to Facility Net in raw
mA values. Scaling may be set in Facility Net to convert the data to real numbers. Use
the following conversion:
Range
= the sensor’s
Maximum
value – the sensor’s
Minimum
value
Example: A temperature probe can measure 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
&
RawData Min
are the values of the entire range of current.
In terms of 4-20 mA electrical Current, the
RawData Max
is 20 and the
RawData Min
is
4.
In some systems with bit lengths, the
RawData Max
is 4095 and the
RawData Min
is
0.
Offset
= Minimum - (Scale *
RawData Min
)
