Command protocol, Command structure – APG IRU-3000 user manual User Manual
Page 7
Rev. A2, 11/08
IRU-2xx4/3xx4
7
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COMMAND PROTOCOL
A command must be sent to the sensor in order to obtain any information from
the unit.
•
All distances coming form the sensor will be in whole millimeters.
•
The temperature is returned as a Celsius value with a 40° positive offset
•
No negative numbers, decimal numbers or fractions are sent.
COMMAND STRUCTURE
All of the IRU-2XX4/3XX4 commands follow the format below.
MEMORY
There are two types of memory available in the IRU-2XX4/3XX4, E
2
and RAM.
E
2
is nonvolatile and will retain the data if power to the sensor is lost or turned
off. RAM is volatile and will not be retained without power. The number of
WRITES available to E
2
is approximately 10,000. Prudent use of this function
will allow a lifetime of use. The number of READS from E
2
is unlimited. If
frequent parameter changes are anticipated or necessary, use the WRITE RAM
functions to avoid “wearing out” the E
2
memory.
Messages from the sensor
Start character
(AAh)
Sensor Number
as single byte value
Command Number
as single byte value
Data values
as double byte value
Stop character
(55h)
6 bytes Total
Messages from the sensor
Start character
(66h)
Sensor Number
as single byte value
Command Number
as single byte value
Data value 0
as double byte value
Data value 1
as single byte value for returning distance and
temperature if possible
Stop character
(99h)
7 bytes total