Rockwell Automation 2755 Enhanced Decoder Series B - Manual (Page 269)

16–4 PCCC Host Commands
Publication 2755-833
– 41H – Response to an unprotected read (01H) command
– 46H – Response to a diagnostic link (06H) command
– 48H – Response to an unprotected write (08H) command
If the CMD byte sent in any of the commands is invalid, the STS
byte will contain 10H.
•
STS
Byte 1 contains the status of a processed command. The table
below lists the STS codes for all commands.
Status Response Codes
Hex Value Meaning
00H Command successful (no errors).
01H Command complete and successful.➀
02H Display buffer is full. ➀
10H Valid command but invalid format or address.
20H Invalid or unsupported command.
30H Hardware fault (reserved and unused).
40H Command successful but no data available
(read command only)
80H Command successful but data truncated.
(read command only)
➀ Applies only to CMD Address 900H or 901H. See page 16–12
•
TNS
Bytes 2 and 3 contain the same transaction number sequence as
the command. The TNS value links the reply to the command.
•
Data
The data area contains data requested by a read command. The
write commands do not return data.
The unprotected read command (01H) performs these decoder
functions:
•
Reads current bar code data
•
Reads decoder configuration data
•
Reads decoder performance indicator, counters, and diagnostics
•
Reads last message to host
Each command returns data to the host that is read from a specific
address of the decoder’s memory. The following sections define each
read command.
Appendix A contains a summary of the memory addresses for all
decoder functions or commands.
Unprotected Read
Command