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Sdi-12 command & response protocol – Xylem H-3311 User Manual

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A

is an upper-case ASCII character.

n

is the new sensor address to be programmed (“0-9”, “A-Z”, “a-z”, “*”, “?”).

NOTE: To verify the new address use the “Identify Command.”

18

SDI-12 COMMAND &
RESPONSE PROTOCOL

example of a “Change sensor address” command:

Command

Response

Description

“aA2!”

“2

Change sensor address to “2”

The “Zero Position” command resets the encoder position counter internal to the H-3301/3311.

This allows for maximum counting range in both the clockwise and counter-clockwise directions.

When the H-3301/3311 is first powered up the position count is automatically reset to zero. After

the unit has been powered up for some time, the Zero Position command provides a means to

reset the position counter.

In most applications the initial position count will be at some undetermined value due to moving

the encoder or adjustment of the float cables. Before programming the offset term (b) of the

mX+b data scaling equation it is important to zero the current position count. This preserves the

maximum dynamic range of the H-3301/3311’s 16-bit position counter(±32768 raw counts). After

the position counter is zeroed, program the mX+b equation to obtain the desired stage using the

extended write offset command (“aXWO”.)

Command

Response

Description

“aXZ!”

“a

Zero the position counter

Where:

a

is the sensor address (“0-9”, “A-Z”, “a-z”, “*”, “?”).

XZ

are upper case characters

This command takes 000 seconds to complete and places no data in the data buffer.

Zero the Position Command

example of an extended “Zero the Position” command:

Command

Response

Description

“aXZ!”

“a

Reset encoder position

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