Mitsubishi Electric QJ71E71-100 User Manual page 216

(2) Issuing a system switching request upon communication error
The E71 mounted with the control system CPU module monitors communications with the connected device on
each connection. If the E71 detects a communication error, it issues a system switching request to the control
system CPU module. The following table lists a communication error that triggers a system switching request.
Communication error
Alive check
ULP timeout
(a) Target connection
The E71 detects communication errors in the connections selected in the redundant settings. The following
table lists connections that can be monitored.
User Connection No.
System Connection
214
After a connection is opened, the existence of the connected device cannot be confirmed.
An ACK response is not returned from the connected device within the TCP ULP timer time.
Target connection
Connection 1 to Connection 16
Auto Open UDP Port
FTP Transmission Port (TCP/IP)
MELSOFT Application Transmission Port (TCP/IP)
MELSOFT Application Transmission Port (UDP/IP), Dedicated Instruction, CC-Link IE,
NET/10(H) Relay Transmission Port
HTTP Port, HTTP Protocol
Description