Comtrol Modbus TCP User Guide - Manual (Page 70)

70 - Chapter 4. Diagnostic and Statistics Pages DeviceMaster UP Modbus/TCP User Guide: 2000447 Rev. I
PLC Interface Diagnostics
Error responses
Displays the number of responses received from the PLC with errors indicated.
This occurs when the PLC returns a response with an error indication. This
may be caused by such things as:
• Invalid PLC address configuration
• Improper PLC configuration
Unexpected Response
Function Codes
Displays the number of unexpected response function codes from either a
Master Receive or Master Transmit mode message. This occurs when a response
was received without an expected function code.
Unknown Response
Destination Ids Displays the number of responses with unknown destination IDs. This occurs
when the PLC returns a response with an unknown destination ID.
Invalid Response Protocol
Types
Displays the number of responses with invalid protocol errors. This occurs
when a response is returned with a protocol other than the Modbus protocol
value of zero.
Failed Modbus/TCP
Connection Attempts Displays the number of failed Modbus/TCP connection attempts to the specified
PLC IP address.
Modbus/TCP Connection
Problems
Displays the number of Modbus/TCP connection attempt problems. This occurs
when the device responds and the connection is made, but there are problems
setting up the connection options.
Possible problems include:
• Setting the TCP connection to TCP_NODELAY.
• Setting the socket connection to SO_OOBINLINE.
• Setting the socket connection to SO_KEEPALIVE
No Available Modbus/TCP
Connection Errors
Displays the number of connections aborted when there are no available
Modbus/TCP connections. This error occurs when the maximum number of 32
Modbus/TCP connections has been reached and the DeviceMaster UP is
attempting to form another Modbus/TCP connection.
Non-Mode Specific Statistics/Diagnostics
Oversized Received Data
Packet Errors Displays the number of received serial or Ethernet data packets that were
larger than the configured maximum receive data packet.
Improper Configuration
Errors
Displays the number of improper configuration errors. These errors occur when
the DeviceMaster UP receives a message that cannot be performed due to an
invalid configuration.
System Resource Errors
Displays the number of system resource errors. These errors indicate a system
error on the DeviceMaster UP such as an inoperable serial port or a full
transmit queue. These errors typically occur when the PLC(s) are sending data
to the DeviceMaster UP faster than the DeviceMaster UP can process it.
Writes to Offline Ethernet
Device on Socket N Displays the number of write attempts by a PLC to the Ethernet device when
the device was offline.
First Error Description Text description of the first error that occurred.
Last Error Description Text description of the last or most recent error that occurred.
Master Mode Specific Statistics (Continued)