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Idesco EPC Anticollision – User Manual
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Many of the commands require the reader to perform a function, but do not require the reader to
send data back to the host. However, since the host cannot send a message until the reader replies,
an ACK is sent.
The ACK message contains no data. It returns the same Command Code that was sent originally to
the reader, sets the Status Word to 0x0000 (zero) and the Data Length to 0x00 (zero).
The following shows an example of an ACK message to a Set Read TX Power command.
FF 00 92 00 00 27 3B
Data
FF
00
92
00 00
27 3B
Length
1 byte
1 byte
1 byte
2 bytes
2 bytes
Description
Header
Length of data field
Command code
Status
CRC
The value in the Command Code field (0x92) is the same as the Set Read TX Power Command
Code, 0x92.
5.2.2. Fault Reply Message
If a problem occurs during the execution of a command, the reader returns a non-zero status value.
Although this usually implies a fault or error, sometimes the nonzero status simply indicates a condition of the system. For instance, when executing a Read Tag Single command, if no tags are found,
a status code of 0x0400 is returned. An example of a fault reply message is shown for the Set Read
TX Power command.
FF 00 92 01 06 26 3D
Data
FF
00
92
01 06
26 3D
Length
1 byte
1 byte
1 byte
2 bytes
2 bytes
Description
Header
Length of data field
Command code
Status
CRC
A list of error codes is included in Chapter 3.5: Error Messages. Refer to this list when encountering
any non-zero status codes.
5.2.3. Data Reply Message
If the requested command requires that the reader returns data, then the reader creates a message
similar to the ACK Message with the data length set to a non-zero value. Since this command does
not require a data field, the length field is set to Zero.
FF 00 92 00 00 27 3B
Data
FF
00
92
Author: Pah
Approved: Ara
Length
1 byte
1 byte
1 byte
Description
Header
Length of data field
Command code
File: C00360E
Date: 28.06.2011
Printed: 07.07.2011
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