Sending And Receiving Messages - Mitsubishi Electric MELSEC iQ-R Series User Manual

9.4

Sending and Receiving Messages

Series
MELSEC-Q series
MELSEC iQ-R series
The SECS/GEM communication software sends and receives SECS messages by handshakes of trigger relays from the
Programmable Controller CPU and the data register.
The format of messages to be sent and received, sending and receiving trigger relays, and mapping of sending and receiving
message items with storage registers must be defined in advance using the setting tool.
Understand the basic structure of SECS message sending and receiving by the SECS/GEM communication software before
using the message sending and receiving function.
Usage method
■Receiving SECS messages
When an SECS message is received from the host, the SECS/GEM communication software stores the received data in the
prescribed register mapped to the corresponding message item, and then the receiving notification trigger relay configured for
the corresponding message is switched on.
The Programmable Controller CPU detects that a message was received by the receiving notification trigger being switched
on, and then extracts the received data from the register. Next, the receiving notification trigger is switched off, and the SECS/
GEM communication software is informed that receipt is complete.
Programmable
Controller CPU
Register
Ö
Õ
Receiving process
×
No. Description

The SECS/GEM communication software receives a SECS message

The received data is stored in the register specified by the item property definition of the message (Page 68 Item information)

The reception notification trigger relay of the programmable controller CPU specified by the message property definition is switched ON (Page 65
Message information)

The programmable controller CPU detects the message reception by the reception notification trigger relay switching ON
 Received data is read from the register

After the received data is read, the reception notification trigger relay is switched OFF

The programmable controller reports receipt completion to the SECS/GEM communication software
The reception notification trigger relay is configured at the "Primary message information" screen or "Secondary message
information" screen. Select the "Reception Notification Trigger" checkbox, and then configure the notification destination.
( Page 65 Message information)
9 SECS/GEM COMMUNICATION SOFTWARE KNOWLEDGE
242
9.4 Sending and Receiving Messages
SECS/GEM communication software
Non-GEM version


SECS/GEM communication
software
Receiving process
Ó
Ø
Ô
GEM version


Host
Sending process
Ò
GEM advanced version

