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PAD Message Set
Chapter 11
115
When you send or receive a PAD command in the Native mode, it
contains all of the fields shown in Figure 11.1. The hexadecimal value of
the SEL field is 06. The STS value is 00. The TNS value distinguishes it
from other PAD commands generated by its message initiator. The LINK,
NODE, and USER values define the destination.
Command Format:
TNS
2 Bytes
USER
NODE
LINK
STS
00
DATA
EXT
FF
SSQ
SEL
06
DATA
DATA (Any Format)
238 Bytes Max.
When a host computer for a 1779-KFM interface receives a PAD
command, it must not send a PAD reply. However, when a host computer
sends a PAD command, the 1779-KFL or 1779-KFM interface at the
destination automatically sends a PAD reply.
Reply Format:
TNS
2 Bytes
USER
NODE
LINK
STS
xx
DATA
EXT
FF
SSQ
SEL
86
When you receive a PAD reply, it does not contain the application-layer
data field of the command. However, the reply contains all of the other
fields in Figure 11.1. The SEL value is 86. The TNS, LINK, NODE, and
USER fields are copied from the command; this helps the command
initiator of your host computer match the command packets with the
Using NativeMode PAD
Messages