Download Type MELSECNET, MELSECNET/B Data Link

7.
DATA LINK SETTINGS
Link parameter setting example
The link parameter setting of the system configuration shown in Fig 7.20 is explained
when the MELSECNET
mode is used.
Fig 7.20 Local system configuration example
(1)
Number of assigned points
(a) Link relays (B) 512 points and link registers (W) 512 points for the master station
(b) Link relays (B) 256 points and link registers (W) 256 points for the local station
No.1
(c) Link relays (B) 512 points and link registers (W) 256 points for the local station
No.2
(d) Link relays (B) 1024 points and link registers (W) 256 points for local station No.3
(2)
Examine the ranges to be assigned with the first and second half link parameters
(a) Because the number of master station link points is 1088 bytes
(512/8 + (512 2) = 1088) , both the first and second half link parameters are
required.
To simplify this explanation, the number of link relays (B) and link registers (W) are
halved and assigned with the first and second half link parameters each.
Although it is possible to assign the link relays (B) only with the first half link
parameters and the link registers (W) only with the second half link parameters,
assign the link relays (B) used for handshake processing with both the first and
second half link parameters.
(b) Only the first half link parameters are required for the local stations (No.1 to 3)
because each station uses less than 1024 link points.
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