Message Wait Time Setting - Mitsubishi MELSEC L Series User Manual

6.4 Message Wait Time Setting

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The message wait time is used during data communications using a MC protocol.
It is the time for an external device that cannot receive the data immediately after it has
been transmitted.
When the Q series C24 transmits a response message in reply to a command
message received from the external device, transmission of the response message is
delayed by the message wait time, or longer.
The following explains the message wait time operation for data communications using
QnA compatible 2C/3C/4C frame. (For A compatible 1C frames, the message wait time
is designated in the command message.)
External
device
Programmable
controller CPU
(1) Q series C24 operation by message wait time
1) When message wait time is 0 ms
If a response message can be transmitted, the Q series C24 immediately
transmits the response message. A transmission wait time is not set.
2) When the message wait time is 10 ms or longer
If a response message can be transmitted, and the message wait time after
reception of the command message has elapsed, the Q series C24 transmits
the response message.
(2) Changing the transmission wait time
The transmission wait time is registered on the GX Configurator-SC's "MC
protocol system setting" screen
POINT
(1) If the external device that must wait a certain time before it can receive a
response message after a command message was transmitted, set the
message wait time as explained above.
Especially, for data communications with an external device connected to the
Q series C24 RS-422/485 interface, set the message wait time to the external
device hardware gate OFF time or longer.
(2) The message wait time described here is the time for data communications
using QnA compatible 2C/3C/4C frame.
6 CHANGING THE DATA COMMUNICATIONS MONITORING TIMES
Command
message
Response
message
Message wait time
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