Rockwell Automation 2755 Enhanced Decoder Series B - Manual (Page 271)

16–6 PCCC Host Commands
Publication 2755-833
0
5
STS= 80H
TNS
High Byte Low Byte
MSB LSB
1
3 2
4
Reply - Truncated Data (Host Buffer Contains More Data)
Data
CMD Reply = 41H
To read the rest of the data in the buffer, send one or more additional
read commands. In each command, offset the address appropriately
from the previous command. A status of 00H is returned in the reply
when the last segment of data from a bar code packet is read. Here is
an example.
The host buffer contains a bar code packet that is 200 bytes. To read
the entire packet, you need to send two read commands. The first
command would read 124 bytes (62 words) of data. The second
command would read the remaining 76 bytes (38 words) of data.
The following table shows the start and end address for each read
command.
Read
Commands
Address
HEX Decimal Read 100 words (200 bytes)
1st Read Command
Start Address 100 256 62 words (124 bytes)
2nd Read Command
Start Address 17C 380 38 words (76 bytes)
Note: By always setting the size of 7C Hex, you will know that the
decoder will always return up to 124 bytes.
Read Counters and Performance Indicator
Counter values (package, output, no-read) and performance data are
stored at addresses 600H to 6FFH. The command format for reading
this data is:
0
2
4
6
5
1
3
7
STS= 00
Read Counter or Performance Indicator Address
TNS
High Byte Low Byte
MSB LSB
CMD= 01H
Size = n
Read Counters and Performance Indicator
00H
Appendix A lists the address and byte size for each counter and the
decoder performance indicator.