Precautions For Settings; Setting Value For Each Timer Of The External Device Side - Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual

Precautions for settings

■Setting value for each timer of the Ethernet-equipped module side.
Set the timer values so that the following formula is met.
Response
TCP ULP
≥
monitoring timer
timer value
value
TCP zero window
TCP resend
=
timer value
timer value
When connecting Mitsubishi products to the line, configure the same settings for both modules.

■Setting value for each timer of the external device side.

Set the timer values 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.
TCP ULP timer
value on the external
device
Monitoring timer value of the
application software on the external
device
*1 "n" is the number of TCP segment transmission and is calculated by the following formula.
Message size sent by the Ethernet-equipped module
n = A value that
Maximum Segment size
Ex.
The number of TCP segment transmission when communications are performed on the same line
The Maximum Segment Size is 1460 bytes on the same line (without a router) and the number of TCP segment transmissions
is as follows.
• n = 1 when the size of the message sent by the Ethernet-equipped module is 1460 bytes or less
• n = 2 when the size of the message sent by the Ethernet-equipped module is greater than 1460 bytes
Ex.
The number of TCP segment transmission when communications are performed on a different line
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 transmissions is as follows.
• n = 1 when the size of the message sent by the Ethernet-equipped module is 536 bytes or less
• n = 2 when the size of the message sent by the Ethernet-equipped module is greater than 536 bytes and no more than
1072 bytes
• n = 3 when the size of the message sent by the Ethernet-equipped module is greater than 1072 bytes and no more than
1608 bytes
TCP
TCP end
≥ ≥
resend
timer value
timer value
TCP resend timer value
>
on the Ethernet-equipped
module
TCP ULP timer value on
>
the Ethernet-equipped × n
module
is rounded up to the nearest integer
IP
>
assembly
timer value
*1
2 PARAMETER SETTINGS
2.3 Application Settings
2
261