Xylem H-3342 - Manual (Page 11)

H-3342
Installation 2-3
2.4 Programming the H-3342
The H-3342 comes from the factory with the following settings:
SDI Address: 0 Power_Mode: 0 (Sleep)
StageSlope: 1.00 4-20mA_Hi: 20.0 Ft
StageOffset : 0.000 4-20mA_Lo: 4.0 Ft
LCD_Digits: 2 (±199.99) SDI_Digits: 3 (±xxx.xxx)
With these values the data will be in units of feet when used with a pulley having a
circumference of 12 inches. The slope can be changed to accommodate other pulley
circumferences or to change the data to other engineering units such as inches or Meters.
The LCD display can display the Stage in one of two formats: ±199.99 or ±19999. By default
SDI-12 measurement data is sent with more precision than will fit on the LCD display. The
default is three digits (x.xxx). Some users prefer to have the SDI-12 measurement data exactly
match the value on the LCD display. If this is the case, use the aXWSDInn command and set
SDI-Digits to 2, such that two digits beyond the decimal point are sent in the SDI-12 response
(x.xx).
The setups are stored in EEPROM within the H-3342 and will not be lost if the power is
disconnected. The extended commands for changing these setups are described in detail in
Chapter 3.
2.5 Programming the SDI-12 Address
If more than one sensor is to be connected to the SDI-12 bus, make certain each sensor has a
different sensor address. The H-3342 comes from the factory with its address set to “0". The
address can be programmed with either an SDI-12 command (see Chapter 3) or using the offset
adjust control on the H-3342's faceplate. To change the address with the adjust control, press and
hold the ‘Read’ button while the H-3342 is being powered up, the display will show the H-3342's
current SDI-12 address. The SDI-12 address may be changed in the range of 0 to 9 using the
adjust screw. When the Read button is released the new SDI-12 address is saved and the display
switches to the normal stage readout. To change the SDI-12 address again, the power must be
disconnected and the special power-up sequence repeated.
2.6 Setting the Stage
Many applications use the shaft encoder to monitor water in a stilling well. A float and pulley
translate the water level to rotation of the encoder’s shaft. Because the H-3342 is an absolute
encoder, the turn count and shaft angle cannot be “reset”. When the H-3342 is first installed, you
will want to adjust the StageOffset such that the LCD display and SDI-12 data correspond to the
current water elevation or stage as determined with a staff gauge or other datum.
With the shaft pointing toward you, rotating the encoder shaft clockwise produces an increasing
(positive) shaft position value. If this is backwards from your needs, either program the
StageSlope with a negative value, or exchange the float and counter weight on the pulley. To
adjust the Stage, press the “Read” button and rotate the Adjust screw on the faceplate. Turn the