Xylem System 5000 User Manual - Manual (Page 36)

are available by selecting either a single channel or the latter paired channels (1-2 or 3-4).
Many analog sensors send back a voltage on a single line that is referenced to ground. These are
called single ended sensors and are the simplest to work with. A simple wind direction sensor
that uses a continuous turn potentiometer is a good example of a single ended sensor.
A differential sensor will have two signal lines referenced to each other, not to ground. A strain
gauge is an example of a differential sensor. The two signal lines would be connected to analog
channels 1 and 2 or 3 and 4 and the corresponding Channels would be selected. The reading
returned from the sensor (as noted by the Analog Value in the bottom left of the screen) is the
difference between the two analog inputs.
INPUTS
Number of Samples
This option allows the user to change the number of samples that are averaged from the analog
input when the analog channel is scanned. The user can change the number of samples to any
number between 1 and 1000. Due to the high 24-bit resolution of the A/D, fewer samples are
needed for an accurate reading compared to traditional A/Ds. Each measurement takes an
average of 0.0375 seconds. Thus if a large number of samples are selected, the scan process for
that particular analog channel will take longer. Generally only a few samples are necessary for an
extremely accurate reading.
Est. Time (sec)
The Estimated Time will be updated as the Number of Samples changes. This number is a simple
calculation of 0.0375 * Number of Samples.
5V Warmup (sec)
Some sensors may require the 5V excitation to supply power for a specified
period of time before a measurement should be taken. For these sensors, a warmup time in
seconds can be specified using this option. For example, if a 5V Warmup of 3 is defined, the
System 5000
™
will wake up, turn the 5V Excitation on, wait for 3 seconds, and then retrieve the
measurement from the selected Channel.
To add a Slope, Offset, or Custom Function to the measured value, use Math & Data Options.
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Basic Program (Input)
Basic Programs can be used as either Inputs, Outputs, or Network Programs. Basic Programs
available to be used as Inputs will be selectable from within the Select Input menus. If no Basic
programs have been installed or selected as Input programs, the Basic Programs group will not be
shown in the Select Input menu.
The image on pg.35 shows a Basic Program with the name H-3531 Flashlite that is being used as an
Input for a Task. If a Basic Program does not have a name declared, the program’s filename
(e.g.rs232Sensor.bas) will be used as the program name and title of the Properties screen.