Mitsubishi Electric MELSEC iQ-R Series User Manual page 54

The following diagram shows the timing to link relays in each method.
Handshake
(for each message)
Handshake
(for each transaction)
None handshake
Processing by Programmable
Controller CPU
Processing by SECS/GEM
communication software
(1) SECS/GEM communication software starts.
(2) Programmable Controller CPU turns off.
(3) Programmable controller CPU starts.
(4) SECS/GEM communication software turns off.
(5) The SECS/GEM communication software starts.
(6) Programmable Controller CPU turns off.
(7) The sending request trigger is detected by the trigger relay switching OFF.
(8) The SECS/GEM communication software starts.
(9) SECS/GEM communication software turns off.
(10) Programmable controller CPU starts.
(11) Programmable Controller CPU turns off.
(12) The trigger is detected when the relay remains ON for the predetermined hold time.
*1 The same sequence applies to the transaction from sending request to reception notification.
7 BASIC FUNCTIONS
52
7.3 Programmable Controller CPU Link Function
Reception
Transmission
Reception
Reception
Transmission
(1)
(5)
(8) (9)
Trigger keep time
*1
(2)
(3)
Transmission
(7)
(6)
(10)
(4)
(11)
(12)