Mitsubishi Melsec-L Series User Manual page 250

(1) Precautions for settings
• Specify the setting value of each timer on the E71 side so that the following formula is met.
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.
*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
248
Response
TCP ULP
monitoring
timer value
timer value
TCP
resend
timer value
TCP resend
timer value on
the connected device
Monitoring timer value of
the application software on
the connected device
Message size sent by the E71
Maximum Segment Size
TCP
TCP end
resend
timer value
timer value
TCP zero window
=
timer value
TCP resend timer value
on the E71
TCP ULP timer value
on the E71
is rounded up to the nearest integer
IP
assembly
timer value
*1
n