NPort 6000 Series
Software Installation/Configuration
10-10
2.
Click the Advanced Setting tab to modify Tx Mode, FIFO, and Flash Flush.
Tx Mode
Hi-Performance is the default for Tx mode. After the driver sends data to the NPort 6000, the driver
immediately issues a “Tx Empty” response to the program. Under Classical mode, the driver will not send
the “Tx Empty” response until after confirmation is received from the NPort 6000’s serial port. This causes
lower throughput. Classical mode is recommended if you want to ensure that all data is sent out before
further processing.
FIFO
If FIFO is Disabled, the NPort 6000 will transmit one byte each time the Tx FIFO becomes empty, and an
Rx interrupt will be generated for each incoming byte. This will result in a faster response and lower
throughput.
Network Timeout
You can use this option to prevent blocking if the target NPort is unavailable.
Auto Network Re-Connection
With this option enabled, the driver will repeatedly attempt to re-establish the TCP connection if the NPort
6000 does not respond to background “check alive” packets.
Return error if network is unavailable
If this option is disabled, the driver will not return any error even when a connection cannot be established
to the NPort 6000. With this option enabled, calling the Win32 Comm function will result in the error return
code “STATUS_NETWORK_UNREACHABLE” when a connection cannot be established to the NPort 6000.
This usually means that your host’s network connection is down, perhaps due to a cable being disconnected.
However, if you can reach other network devices, it may be that the NPort 6000 is not powered on or is
disconnected. Note that Auto Network Re-Connection must be enabled in order to use this function.
Fast Flush (only flushes the local buffer)
For some applications, the user’s program will use the Win32 “PurgeComm()” function before it reads or
writes data. After a program uses this PurgeComm() function, the NPort driver continues to query the
NPort’s firmware several times to make sure no data is queued in the NPort’s firmware buffer, rather than
just flushing the local buffer. This design is used to satisfy some special considerations. However, it may
take more time (about several hundred milliseconds) than a native COM1 due to the additional time spent
communicating across the Ethernet. This is why PurgeComm() works significantly faster with native COM
ports on the PC than with mapped COM ports on the NPort 6000. In order to accommodate other
applications that require a faster response time, the new NPort driver implements a new Fast Flush option.
By default, this function is enabled.
If you have disabled Fast Flush and find that COM ports mapped to the NPort 6000 perform markedly slower
than when using a native COM port, try to verify if “PurgeComm()” functions are used in your application.
If so, try enabling the Fast Flush function and see if there is a significant improvement in performance.
