Mitsubishi MELSEC LJ71C24, User Manual

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10 DATA COMMUNICATION USING THE NONPROCEDURAL PROTOCOL
POINT
(1) The position and size of the transmission area in the buffer memory can be
changed with GX Works2 in accordance with the specifications of the external
device and the received data length.
(a) When changing the position and size of the transmission area in the buffer
memory with GX Works2, specify as follows:
1) [Various_Control_Specification] screen "For designation of
transmission area" "Transmission buffer memory head address
designation"
Designate the starting address for the area to be used as the
transmission area in the setting area (address: 400
H
to 1AFF
H
, 2600
H
to 3FFF
H
).
2) [Various_Control_Specification] screen "For designation of
transmission area" "Transmission buffer memory length
designation"
Designate by addresses the length of the area (0001
H
to 1A00
H
) to be
used as the transmission area in the setting area (address: 400
H
to
1AFF
H
, 2600
H
to 3FFF
H
).
(b) When changing the position and size of the receive area in the buffer
memory, if any of the functions below are used concurrently, make sure
that the addresses of the transmission area do not overlap with the buffer
memory addresses assigned for storing transmission/receive data with the
functions.
1) MC protocol buffer memory read/write function
2) MC protocol on-demand function
3) Predefined protocol function (transmission/reception data storage
area)
4) Nonprocedural protocol transmission/receive function
5) Bidirectional protocol transmission/receive function
6) Communication data monitoring function
(2) Set the size of data per data transmission from the CPU module to the external
device so that it is smaller than the size of the transmission data designated
area in the buffer memory.
(Transmission data designation area)
≥
(Size of arbitrary data portion to be
sent from the CPU module)
To transmit data whose size is larger than the transmission data designation area,
increase the transmission area, or divide the transmission data before sending.