Comtrol Modbus TCP User Guide - Manual (Page 32)

32 - Chapter 2. Programming Interface DeviceMaster UP Modbus/TCP User Guide: 2000447 Rev. I
Retrieve Statistics Message
Overrun Error Count
This attribute counts the number of packets with overrun type errors
received on the serial port.
Unexpected Transmit
Sequence Number Error Count
This attribute counts the number of Unexpected Transmit Sequence
Number errors. The DeviceMaster UP increments this number when it
receives a raw data transmit message with a sequence number that is not
equal to either the previous sequence number or the previous sequence
number plus one. (The DeviceMaster UP expects this sequence number to
be incremented by one with each new transmit message.)
Invalid Modbus/RTU Device
Responses
The number of invalid messages returned from Modbus/RTU devices on this
port. Such invalid responses could be the result of any or all of the following:
• Invalid CRC
• Invalid returned function code
• Invalid Unit Identifier
• Duplicate Unit Identifier
Modbus/RTU Device Timeouts
The number of messages that timed out waiting for a response from a
Modbus/RTU device on this port.
Retrieve Statistics Message Description (Continued)