AMCI SMD23E2 Series, Руководство пользователя

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SMD23E2 & SMD24E2 S
PECIFICATIONS
SMD23E2 and SMD24E2 User Manual
ADVANCED MICRO CONTROLS INC.
14
The SMD23E2 and SMD24E2 Families (continued)
Network Data Format (continued)
The other data format is a signed thirty-two bit integer format. When using the thirty-two bit format, there is
one additional parameter named
Data Endian . Its use is best explained with an example. The value of
123,456 equals 0001:E240 in hexadecimal. When storing and transmitting this data, some host controllers
will store the least significant word (16#E240) in the lower addressed word in their data tables, while others
will store the most significant word (16#0001) stored in the lower addressed word in their data tables. These
controllers expect thirty-two bit values to be returned to them using the same format. Least significant word
first is called
little endian , most significant word first is called big endian . Rockwell Automation controllers
use little endian format, while the default Modbus format is big endian .
The range of values when using the multi-word format is -32,768,000 to 32,767,999. When
used in continuous rotation applications, it is possible to overflow these values. When a posi-
tion value overflows, the value of the associated data words will become indeterminate. AMCI
strongly suggests using the signed 32-bit integer format for continuous rotation applications.
EtherNet/IP applications that use an EDS file have the parameters and data values defined as
double integers. In these applications, the data formats should be programmed to the thirty-
two bit integer format and the Data Endian parameter should be set to
little endian .