Send Monitoring Time (Timer 2) Setting; C24 Operation By Send Monitoring Time (Timer 2) - Mitsubishi Electric MELSEC iQ-R Series User Manual

10.3

Send Monitoring Time (timer 2) Setting

The send monitoring time (timer 2) is a monitoring time for clearing the wait state of C24 when C24, which is to transmit a
message or response message (result), is placed into the data transmit wait state due to any trouble of the target device side
When C24 transmits a message, it monitors the wait time up to the end of transmission of the message.
When C24 received a message from a target device, it monitors the wait time up to the end of transmission of the response
message.
The following explains the send monitoring time (timer 2) operation.
Target device Message
CPU module
If on-demand data is transmitted before a response message during data communications using the MC protocol, each time is
monitored.
Command
Target device
message
CPU module

C24 operation by send monitoring time (timer 2)

When send monitoring time (timer 2) is set to 0 ms
• The time until transmission of a message or response message has been completed is not monitored.
• If C24 cannot transmit, it waits infinitely.
When send monitoring time (timer 2) is set to 100 ms or longer
• C24 monitors the time from completion of message or response message transmission preparations to the end of
transmission, and returns the elapsed time to 0 at the end of transmission.
At time-out, C24 performs the following processing.
■Data communications using MC protocol
• While waiting for the end of transmission of the response message, C24 stores the error code to the 'Data transmission
result' (Un\G599/615) for the target interface.
C24 enters the state in which it waits to receive the next command message without sending a response message (NAK
message) to the target device.
• During on-demand data transmission, C24 stores the error code to the 'On-demand execution results' (Un\G598/614) for
the target interface.
• If transmission was terminated midway in either of the cases above, C24 does not transmit the remaining data.
Response message Message
Monitoring time
Monitoring time
Elapsed time reset
Response
On-demand data
message
Monitoring time
Monitoring time
10 CHANGING DATA COMMUNICATION MONITORING TIME
Response message
Elapsed time reset
10.3 Send Monitoring Time (timer 2) Setting
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