FPΣ User's Manual
8.6 Program Controlled Communication
187
8.6 Program Controlled Communication
With program controlled communication, the user generates a program which governs the
data transfer between a PLC and one or more external devices connected to the
communication port. By this, any standard or user protocol can be programmed.
Typically, such a user program consists of sending and receiving the data. The data to be
sent and the data received are stored in data register areas defined as send and receive
buffers.
RS-232C
POWER READY
MODE
A
B
C
KEY PAD
CAMERA
MONITOR
COM COM D2 D4 D6 D8 D9
FLASH
D1 D3 D5 D7
READY
MICRO-IMAGECHECKER
M100
Matsuhita Electronic Works, Ltd.
24VDC
START
ACK IN1 IN3 IN5
COM COM IN2 IN4 COM
Data registers (DT)
Send buffer
Receive buffer
Receiving data
Image checker
Bar code reader
Sending data using F159_MTRN
PLC
Program controlled connection between the FPΣ and an external device
Sending data
Sending includes generating the data for the send buffer and sending it using the instruction
F159_MTRN. (See also "
Sending Data to External Devices" on page 189.) Sending can be
controlled by the "transmission done" flag. (See also "
Flag Operation in Program Controlled
Communication" on page
198.)
Writing data
Data register (DT)
Send buffer
Receive buffer
Device with
RS232C port
Sending data using F159_MTRN
PLC
The start and end codes specified in the system registers are automatically added to the data
sent. The maximum volume of data that can be sent is 2048 bytes.
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