Handshake (For Each Transaction) - Mitsubishi Electric MELSEC iQ-R Series User Manual

Handshake (for each transaction)

This section shows the operation flow to link trigger relays by handshakes for each transaction.
The following section is an example of when receiving a message from the host.
Programmable
controller CPU
(4)
(5)
(6)
(7)
The trigger relay is
turned off.
(1) A message is received from the host.
(2) The SECS/GEM communication software stores the received data in the shared memory/device.
(3) SECS/GEM communication software turns the trigger relay ON (OFF→ON control) to inform the Programmable Controller CPU of the reception.
(4) The programmable controller CPU detects the trigger relay.
(5) After the programmable controller CPU acquires the received data in the shared memory/device, the received data is processed by a program of the
programmable controller CPU. At this time, the programmable controller CPU does not turn the trigger relay OFF.
(6) The programmable controller CPU configures the sending data to the shared memory/device.
(7) The Programmable Controller CPU turns the trigger relay OFF (ON→OFF control) to request a transmission.
(8) The SECS/GEM communication software detects the trigger relay.
(9) The SECS/GEM communication software acquires the data of the item section of the sending transaction from the shared memory/device of the
programmable controller CPU.
(10) After editing the data into a SECS- transaction message, SECS/GEM communication software transmits the message to the host.
The procedure when data is sent from the programmable controller CPU is the same as above.
The programmable controller CPU stores the sending data in the shared memory/device, and then turns the trigger relay ON.
During return receipt, the SECS/GEM communication software stores the received data in the shared memory/device, and
then switches the trigger relay OFF.
After this, the programmable controller CPU acquires the data.
SECS/GEM communication
Shared memory/
Device
(2)
(3)
The trigger relay is
turned on.
(8)
(9)
software
(1)
(10)
7.3 Programmable Controller CPU Link Function
Host
7 BASIC FUNCTIONS
7
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