Existence Confirmation - Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual

Item

Existence Confirmation

*1 When "Q Compatible Ethernet" is selected in the network type, the setting range is 1 to 16.
*2 This setting is not available for the CPU module (built-in Ethernet port part).
*3 This setting is not available when the RJ71EN71 network type is set to "Q Compatible Ethernet".
*4 When the automatic detection of the connected devices is executed, the values read from the connected devices will be the default.
*5 When "Communication Method" is set to "OPS Connection", 255.255.255.255 can be set.
Comment can be set on the "Properties" window displayed by right-clicking the module in "List of devices" or
"Device map area" and selecting "Properties". The following can be performed depending on the selected
device.
• Changing the image
• Creating association with a file or application
■Existence Confirmation
When the Ethernet-equipped module has not communicated with the external device for a certain period of time while the
connection is open, this function checks whether the external device is alive by sending an alive check message to the device
and waiting for the response.
The following table lists the details on alive check.
Item
KeepAlive
UDP
Do not confirm existence
*1 The connection may be disconnected if the external device does not support the TCP KeepAlive function (response to a KeepAlive ACK
message).
*2 The Ethernet-equipped module automatically sends an echo response packet when it receives a PING echo request command. (It
sends a response to the received PING command even if the connection used in the data communications with the external device is
closed.)
If a response message cannot be received from the external device (or if an error has been detected) using the alive check
function, the following are performed.
• The corresponding connection will be forcibly closed. (The line is disconnected.) Open the connection again using a user
program.
• Open completion signal is turned off, and the error code is stored in the buffer memory areas.
2 PARAMETER SETTINGS
246
2.2 Basic Settings
Description
Select the method of alive check which is performed when the
Ethernet-equipped module has not communicated with the external
device for a certain period of time. When the module cannot
communicate with the external device, the connection will be closed.
( Page 246 Existence Confirmation)
Applicable protocol Description
TCP/IP This method is used for a connection opened using TCP/IP. The Ethernet-equipped module performs
an alive check by sending an alive check ACK message to the external device with which
communications have not been performed for a certain period of time and waiting to see whether the
response is received.
The connection will be automatically closed when the open state is not continued.
UDP/IP This method is used for a connection opened using UDP/IP. The Ethernet-equipped module performs
an alive check by sending the PING command (ICMP echo request/response function) to the external
device with which communications have not been performed for a certain period of time and waiting to
see whether the response is received.
TCP/IP, UDP/IP Alive check is not performed.
Setting range
• KeepAlive
• UDP
• Do not confirm existence
*2
*1