Rockwell Automation 1771-DB BASIC MODULE User Manual
Page 297
Chapter
Call Routines 69–127
13
13 -39
Operational Codes for Half-Duplex Mode:
Operational
code
Corresponding mode of operation
Special operational code
(same as 0 - 11 except
EOT is suppressed)
0
NHS, Disable DPD, BCC Error Checking
32
1
NHS, Enable DPD, BCC Error Checking
33
2
NHS, Disable DPD, CRC Error Checking
34
3
NHS, Enable DPD, CRC Error Checking
35
4
HDMwoCC, Disable DPD, BCC Error Checking
36
5
HDMwoCC, Enable DPD, BCC Error Checking
37
6
HDMwoCC, Disable DPD, CRC Error Checking
38
7
HDMwoCC, Enable DPD, CRC Error Checking
39
8
HDMwCC, Disable DPD, BCC Error Checking
40
9
HDMwCC, Enable DPD, BCC Error Checking
41
10
HDMwCC, Disable DPD, CRC Error Checking
42
11
HDMwCC, Enable DPD, CRC Error Checking
43
A special range of operational codes (32 - 43) are also accepted.
These codes are identical to codes 0 - 11 except that the end of
transmission (EOT) packets are suppressed. This operation is a deviation
from the standard DF1 protocol and should only be used where
transmissions from a slave module are minimized. When using one of
these selections, the DF1 driver does not respond to ENQuires from a DF1
master unless there is a data packet transmitted.