Advantech B+B SmartWorx 232BSS4, Руководство пользователя

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Documentation Number 232BSS4-2916m 15
When the specified Port Time has elapsed, the 232BSS4 checks in
sequence for other Slave ports with buffered data and switches to them.
If no other Slave ports need access to the Master, the current Slave port
will again be connected until another Port Time has elapsed.
Inactivity Time:
The Inactivity Timer tracks how long a Slave port has been idle. The
Inactivity Time is reset any time data is received on the connected Slave
port or sent out the Master Port. This way, if the Master port is slower
than the connected Slave port, the Slave port is not considered inactive
while waiting for the Master to catch up.
Inactivity Time is set through the setup software. Times are set in
milliseconds and can be anywhere in the range of 0 to 65,000 (65
seconds). A value of zero for the Inactivity Time would give the
transmitting Slave port access to the Master until a Port Timeout was
reached or until a specific Turn Off command was sent from the Master
device.
Port and Inactivity Time Setup Tips:
Normally, the Inactivity Time should be set lower than the Port
Time. Setting a zero for either value allows the other to have full control
of port switching. Setting a value of zero for both timeouts keeps the
Slave port connected until explicitly turned off by the Master device
through the Turn Off all ports command.
Slave Preamble:
Each Slave can be programmed to transmit a preamble to the
Master device when the Slave becomes connected. This tells the Master
device which new Slave is sending data. The preamble is set in the
setup software and can be any character sequence up to four characters
long. The preamble is sent to the Master device whenever a port is
selected through commands or when the port will be sending data to the
Master device because of an automatic switch.