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4. FUNCTIONS
4.
FUNCTIONS
4.1 I/O Communication Functions
This section describes the functions.
The DN91 offers the following two types of functions. Proper parameter setting is required in
advance.
•
I/O communication functions (see Section 4.1)
•
message communication functions (see Section 4.2)
The I/O communication functions conduct I/O data communication with the slave stations.
The I/O communication functions allow the communication type to be set to match the slave
station specification. Four connection types are available: polling, bit strobe, change of state,
and cyclic. The connection type can be set using parameters.
PLC CPU
SET
Y(n+1)7
Xn7 Parameter set complete
SET
Y(n+1)1
Refresh command
FROM
Xn1
Refreshing
TO
Xn1
Refreshing
[Parameter Set]
1)
Write parameters onto the "Parameter" area of the buffer memory, and turn ON the
parameter setting request (Y(n+1)1) via the sequence program to set the parameters.
When the parameters are successfully written, the Parameter Setting Complete (Xn7)
automatically turns ON.
Once the parameters are set, no subsequent parameter setting is required as long as no
change in the parameters is necessary.
When setting the parameters via the configuration software, do not use the sequence
program to set the parameters.
[Refresh]
2)
Communication with the slave stations starts when the refresh request signal (Y(n+1)1)
turns ON.
DN91
1)
Parameter set
2)
Refresh request
Refreshing
4)
0000
H
Iinput data
area
007F
H
5)
0080
H
H
Output data
area
00FF
H
−
4
1
MELSEC-A
Slave station
3)
Input
6)
Output
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