Item Data Size
The Item Data Size is the total size of the Item Data. If the Item Data Size is greater than 128 characters, fragmentation is
used (see the fragmentation example in
Example of Message Transmissions in Action
on page 66).
Input Bits
The Input Bits attribute is a bitmap used to read the state of the 8 discrete inputs from the ABR reader.
Failure Code
The Failure Code is set when an error occurs with the reader. The following is a table of Failure Codes:
Failure Code
Name
0×01
Input Failure
0×02
Communications Failure
0×04
Reader Failure
0×08
Software Error
0×10
Remote Failure
Fragment Sequence Number
The Fragment Sequence Number is set to 1 on the first fragment of the latest Item Data transmission, when the Item
Sequence Number increments up by 1. The Fragment Sequence Number is incremented by 1 on every new fragment. If
fragmentation is not used, this value is fixed at 1. This value will only increment when the Last Fragment Sequence Number
is set to match the current Fragment Sequence Number, to report that the PLC is ready for the next data. The value is only
equal to 0 immediately after a power-up, before the first message is sent.
Fragment Data Size
The Fragment Data Size is the length of the data (in bytes) stored in the Fragment Data attribute. If fragmentation is used,
this value equals 128 until the last fragment.
Fragment Data
This attribute stores the Fragment Data, which are the output messages from the ABR. If the Item Data Size is less than
128, this attribute stores the complete Item Data. If the Item Data Size is greater than 128, this attribute stores the individual
fragments of data.
Example of Message Transmissions in Action
The following is an example of how a PLC receives two Items, one 100 bytes, and the next one 800 bytes, exactly as is
done automatically in the I/O Data Add On Instruction (AOI) available on
. The order is the
same whether two reading attempts completed in quick succession before the PLC finished reading the first result, or
whether they happened with a long period of time in between.
To
ABR
from PLC
To PLC from
ABR
Last Item
Sequence
Number
Last
Fragment
Sequence
Number
Item
Sequence
Number
Fragment
Sequence
Number
Item Size
Fragment
Size
Fragment
Data Buffer
Description
0
0
0
0
0
0
NULL
Power Up
1
1
100
100
[0–99]
ABR sends fragment 1 of item 1
1
0
PLC acknowledges item 1
2
1
800
128
[0–127]
ABR sends fragment 1 of item 2
1
1
PLC acknowledges fragment 1
ABR 7000 Series Barcode Reader
66
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