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7 Serial Communications
NX-series Communications Interface Units User’s Manual (W540)
7-3 Data Used by the Serial Communications Protocol
7
7-3-2 SIDs and SID Responses
7 Second
input
response
• The communications master outputs
the
following output notification data.
• The communications master sets the
Inpu
t SID Response to the value of
the Input SID (02 hex) to tell the CIF
Unit that the communications master
has normally received the second
input data.
• The CIF Unit receives th
e output notifica-
ti
on data given on the left.
• The CIF Unit knows that the CPU Unit or
commun
ications master has normally
received the second input data because
the Input SID Response in the output noti-
fication data is 02 hex.
8 Comple-
tion of
d
ata input
• The communications master
re
ceives th
e input notification data
given on the right.
• The communications master checks
the Input
SID.
• The Input SID is still 02 hex, so the
master know
s that there is no new
input data included in the input notifi-
cation data that was received.
• The CIF Unit inputs the following input
notification
d
ata.
• The CIF Unit leaves the Input SID set to
02 hex to te
ll th
e CPU Unit or communica-
tions master that no i
npu
t data is included
in the input notification data.
*1. Output notification data is output from the CPU Unit or communications master to the CIF Unit.
: Input notification data is input from the CIF Unit to the CPU Unit or communications master.
Step Process
CPU Unit or communications master
processing
Communi-
cations
direction
*1
CIF Unit processing
-
02 hex
-
-
-
-
Output SID
Input SID
Response
Output Data
Type
Output Sub Info
Output Data
Length
Output Data
-
02 hex
-
-
-
-
None
Input Data
Port Status
Input SID
Output SID
Response
Input Data Type
Input Sub Info
Input Data Length
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