Specifications
Web browser based management
UMMBRG300-1101 17
Figure5.3:Modbus status page
This page shows accumulated readings since the MBRG-300 was last activated or
reset. If power to the MBRG-300 is lost, all cumulative values are reset to zero.
The following statistics are maintained:
TCP status
Status of the TCP/IP connection as per TCP finite state machine (refer to RFC 793).
If no client is connected the status indicates LISTEN. If a client is connected, it’s IP
address is shown.
Accumulative connections
A counter that increments each time a client opens a Modbus/TCP connection.
Requests
A counter that increments each time an inbound request message is successfully
received.
Replies
A counter that is incremented each time a reply message is sent back to the master.
This includes exception replies.
CRC errors
A counter that increments each time a message is received that has a CRC that does
not match what is calculated. Typically the result of wiring issues. Messages with CRC
errors are discarded and not replied to.
Invalid frames
A counter that increments each time a malformed Modbus frame is detected.
Malformed frames are for example messages larger than the allowed maximum PDU
size defined in the Modbus standards. This can be caused by non-Modbus traffic on
the network.
Rx time-outs (Modbus serial line)
A counter that increments each time an inter-character time-out occurred during the
reception of an inbound message.
Rx time-outs (Modbus/TCP)
A counter that increments if the master connection has timed out. Subsequently the
connection is terminated by the MBRG-300. A time-out occurs if no Modbus request
is received from a connected client within a 10 second period.
Tx time-outs
Number time-outs occurred when attempting to send a reply message.
The cumulative diagnostic data is reset when the device is power cycled or reset. The
data is also reset by pressing the Clear Counter button.