Xylem H-3521 - Manual (Page 17)

H-3521
Installation 2-7
settings can also be changed using the simple RS232 menu, see Chapter 4.
MeanCount is the number of raw pressure measurements averaged together to make one
measurement sequence. This setting determines how long the sensor will take to make a
measurement. MeanCount can be changed as described in chapters 4 and 5.
2.10.1 Setting the Stage
Many applications use the pressure sensor to measure water level in a gauge or reservoir. The
sensor translates water pressure to water level. When the H-3521 is first installed, you will want
to adjust the Offset such that the measurement data (Stage) corresponds to the current water
elevation or stage as determined with a staff gauge or other datum.
One of the ways to do this is by using the RS232 simple menu interface via Hyperterminal or
other similar terminal program. See chapter 4 section Connecting to the H-3521. Once you have
established connection your screen will look similar to the screen image below. When the user
sets the stage, the H-3521 makes a fresh measurement and automatically updates the Offset as
needed to produce the desired Stage. To set the stage using the RS-232 menu press ‘S’ for “S -
Stage:” and enter in the current stage value and then press enter. Then press the ‘M’ key for “M -
Measure” and verify that the set stage command did execute. You should see that the offset
value has changed. The other way to set the stage is to send the extended SDI-12 “Set Current
Stage” command. The “aXSCSdd.d!” command is discussed in more detail in section chapter 5.