4. FUNCTIONS
4
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1
MELSEC-A
4. 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)
4.1 I/O Communication Functions
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.
[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.
Slave station
DN91
PLC CPU
SET
Y(n+1)7
007F
H
5)
1)
2)
4)
6)
3)
0000
H
Input
Iinput data
area
Refreshing
Refresh request
Parameter set
Xn1
Refreshing
Xn1
Refreshing
Xn7 Parameter set complete
00FF
H
0080
H
H
Output
Output data
area
FROM
TO
SET
Y(n+1)1
Refresh command
