User`s manual

NPort 5600-8-DT User’s Manual Using NPort Administrator
8-20
In the Advanced Settings tab, you may configure how serial data is transmitted from the PC to the
NPort device port.
Tx Mode
Hi-Performance is the default for Tx mode. After the driver sends data to the NPort, 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. This
causes lower throughput. Classical mode is recommended if you want to ensure that all data is
sent out before further processing.
FIFO
When “FIFO” is disabled, the selected device port will send one byte each time the Tx FIFO
becomes empty, and an Rx interrupt will be generated for each incoming byte. This will cause a
faster response time but lower throughput.
Network Timeout
“Network Timeout” specifies how long the driver will wait for the attached serial device to
respond to an open, close or serial parameter change operation. If a response is received by the
specified time, the operation will time out. The default value is 5000 milliseconds.
Fast Flush
“Fast Flush” is designed to improve response times for applications that use the Win32
PurgeComm() function. When Fast Flush is enabled, the Real COM driver only flushes the local
buffer on the host when it receives the PurgeComm() function call. When disabled, applications
that use PurgeComm() may perform markedly slower, because the Real COM driver will need to
also flush the remote buffer, which requires repeated queries of the NPort to make sure no data is
queued in the remote buffer. The repeated queries can cause a performance hit due to the
additional time spent communicating over the network, typically about several hundred
milliseconds when compared to COM ports. If your application uses PurgeComm() and
performance seems sluggish, try enabling Fast Flush.