1 FUNCTIONS
1.5 Communications Using the Fixed Buffer
69
1
Applicable dedicated instructions
The following table lists the dedicated instructions used for communications using the fixed buffer.
For details on dedicated instructions, refer to the following.
MELSEC iQ-R Programming Manual (Module Dedicated Instructions)
List of dedicated instructions
The following table lists the dedicated instructions used by each module.
*1 This function cannot be used when "Q Compatible Ethernet" is selected in the network type.
Applicable connections
The connections No.1 to 16 of the P1 connector can be used for the communications using the fixed buffer.
Communications using the fixed buffer cannot be used with the P2 connector.
Communication structure
This section describes the mechanism of communication with fixed buffer communication.
Data flow
Dedicated instructions are used to send and receive data in fixed buffer communication ( Page 69 Applicable dedicated
instructions)
With "Procedure Exist", the CPU module and external device exchange data one-on-one. A handshake is established with the
external device when sending data form the CPU module and receiving data from the external device.
With "No Procedure", data is sent from the CPU module and received from the external device without a procedure.
Instruction Description
GP.CONOPEN
*1
Establishes a connection.
OPEN
GP.CONCLOSE
*1
Closes the connection.
CLOSE
BUFRCV Reads the receive data from the external device.
BUFRCVS Reads the receive data with an interrupt program.
BUFSND Sends data to the external device.
No.1
No.2
No.3
No.4
No.16
RJ71EN71
External device
BUFSND instruction
BUFRCV instruction
Fixed buffer
CPU module
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