Mitsubishi Electric MELSEC-L SERIES Basic User Manual page 315

(1) Precautions for settings
• Specify the setting value of each timer on the E71 side so that the following formula is met.
Response
monitoring
timer value
When connecting Mitsubishi products to the line, configure the same settings for both modules.
• Specify the setting value of each timer on the connected device side so that the following formula is met. The
frequency of a communication error, such as a transmission timeout, may be higher if the timer values do not
meet the formula.
Monitoring timer value of
the application software on
the connected device
*1 "n" is the number of TCP segment transmission and is calculated by the following formula.
n = A value that
The number of TCP segment transmission when communications are performed on the same line
Ex.
The Maximum Segment Size is 1460 bytes on the same line (without a router) and the number of TCP
Segment transmission is as follows.
• n = 1 when the size of the message sent by the E71 is 1460 bytes or less
• n = 2 when the size of the message sent by the E71 is greater than 1460 bytes
The number of TCP segment transmission when communications are performed on a different line
Ex.
The Maximum Segment Size is at least 536 bytes on another line (via a dialup router or other
communication device) and the number of TCP Segment transmission is as follows.
• n = 1 when the size of the message sent by the E71 is 536 bytes or less
• n = 2 when the size of the message sent by the E71 is greater than 536 bytes and no more than
1072 bytes
• n = 3 when the size of the message sent by the E71 is greater than 1072 bytes and no more than
1608 bytes
TCP ULP TCP end
timer value timer value
TCP
TCP zero window
resend =
timer value
timer value
TCP ULP
TCP resend timer value
timer value on
the connected device
TCP ULP timer value
on the E71
Message size sent by the E71
Maximum Segment Size
TCP IP
resend assembly
timer value timer value
on the E71
n *1
is rounded up to the nearest integer
APPENDICES
A
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