User guide

External control user guide
March 27, 2015 Version 1.7.2.0 31
.
keepAlive command
Command
keepAlive
Shortcut
ka
Arguments
seconds
Availability
when logged in
Purpose
Starts a watchdog timer, requiring the client to communicate within that
period or be disconnected. It is recommended that keepAlive be used to
ensure that TCP/IP client connections get closed in the face of network
failures (or even just unplugging and plugging in network connections). If
the network goes down and the client attempts to communicate, the client
will get a timeout and disconnect, reconnecting once the network is
restored. The server, however, would normally have no way of knowing
that the client gave up on its first connection and reconnected, so server
network stack resources consumed over time. keepAlive solves this
problem.
Notes
You can disable the watchdog timer with an argument of zero. This
command applies to TCP/IP only, not to the serial port.
Response
Something like this: keepAlive 10
Usage Example
The client issues:
keepAlive 120\r
or
ka 120\r
Response
keepAlive 120\r\n
Possible Error Messages
\aOverflow\r\n
\aBadArgumentCount\r\n
\anotLoggedIn\r\n