Programmable Controller Cpu Link Function - Mitsubishi Electric MELSEC iQ-R Series User Manual

7.3

Programmable Controller CPU Link Function

Series
MELSEC-Q series
MELSEC iQ-R series
A relay must be linked between the programmable controller CPU and the SECS/GEM communication software when
messages are transmitted.
There are three methods to link the relay.
• Handshake (for each transaction)
• Handshake (for each message)
• None handshake
The following table shows the features of each method.
Type Handshake (for each
transaction)
Relay • A same relay is used for both
reception and transmission.
• Number of relays used = Number of
transactions
Primary message reception →
Operation of relay
secondary message sending:
SECS/GEM communication software
turns the relay ON during a reception
notification, and then programmable
controller turns the relay OFF during a
sending request.
Primary message sending → secondary
message reception:
The programmable controller turns the
relay ON during a sending request, and
then SECS/GEM communication
software turns the relay OFF during a
reception notification.
Ladder programming Processing is necessary to switch the
trigger detection method ON or OFF
depending on the distinction of the
operations above.
Link with programmable Detectable for each transaction
controller CPU
Feature This mode cannot be used for S9
related messages (only primary
messages) or messages subject to
spooning (no secondary message
during spooling)
SECS/GEM communication software
Non-GEM version


Handshake (for each message)
• Different relays are used for reception and transmission.
• Number of relays used = Number of transactions × 2
Reception:
The SECS/GEM communication
software turns the relay ON, and then
sends notification, and then the
programmable controller turns the relay
OFF.
Transmission:
The Programmable Controller CPU
turns the relay ON to request the
transmission and then SECS/GEM
communication software turns the relay
OFF.
A same trigger detection mechanism
should be used.
Detectable for each message
Precise processing is available for each
message.
GEM version


None handshake
Reception:
The SECS/GEM communication
software turns the relay ON, and then
turns it OFF after keeping the trigger for
a predetermined time.
Transmission:
The programmable controller CPU turns
the relay ON, and then turns it OFF after
holding the trigger for a predetermined
time.
A same trigger detection mechanism
should be used, but the system should
be programmed to turn the transmission
request relay OFF after a fixed
monitoring time and to prevent double
detection after the receive notification
detection.
This mode has less effect on existing
ladders and is preferred for modifying
existing equipment into an on-line
system.
7.3 Programmable Controller CPU Link Function
GEM advanced version


7 BASIC FUNCTIONS
7
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