Inactive Timeout
Inactive timeout allows TRP-C31M to tear down a TCP/IP connection when there is no activity for a
period of time. In case there is a networks failure or power outage. All the TCP/IP connection
resource would be occupied by previous connection that prevent from TRP-C31M to accept further
incoming connection.
Maximum Connection
This parameter defines the number of TCP connection to the gateway in either MODBUS TCP
master or slave mode. The maximum number of the connection is 8. When TRP-C31M is set as
gateway of TCP master to serial slave, it can accept Polling/Query from up to 8 different TCP
masters. Each query will handle in sequence since MODBUS serial interface can only handle one
query at a time. All other queries will be queued until the previous query is finished or timeout.
TRP-C31M can queue up to 8 queries. If there are more than 8 queries at one time, those queries
will be discarded and eventually TCP master will get a timeout.
Gateway Type
This parameter defines what kind of MODBUS devices which TRP-C31M is connected to. There
are two types of connection.
•
MODBUS TCP master to MODBUS serial slave.
•
MODBUS TCP slave to MODBUS serial master.
The default setting is MODBUS TCP master to MODBUS serial slave. Each serial port in
TRP-C31M can be configured into different gateway type.
Listening TCP port
The default listening MODBUS TCP port number is 502. It is recommended to use port number
larger than 1024, if use TCP port number other than 502. Since most of TCP port number under
1024 are used by particular protocol.
Use MBAP’s UID or Use Specific UID
If this parameter is enabled, TRP-C31M will extract the UID in MBAP’s header and convert the
message into MODBUS serial format with the extracted UID. If this parameter is disabled,
TRP-C31M sends the converted message to MODBUS serial slave device with UID defined in the
“Use Specific UID” field.
Generate exception
When this parameter is enabled, TRP-C31M will generate exception message when slave device
does not response to the query command or message timeout.