RS485 TO ETH ( B)
8 . 2 . HEARTBEAT PACKAGE
The heartbeat packet is mainly used to detect whether the communication link is
disconnected. The method of implementation is that the device sends a heartbeat packet data to
the server software at regular intervals. This data will be discarded after being received by the
server and will not be regarded as valid communication data.
The heartbeat packet has two main functions: First, it can let the host computer software
know that the device is active; secondly, if the device fails to send the heartbeat, the device at
the TCP client will automatically re-establish the TCP connection, so it is a recovery network
communication A means.
Figure 34 Keep Alive Time
As shown in Figure 3 4 , the sending time of the heartbeat packet is set by the " Keep Alive
Time".
8 . 2 . 1 . IMPLIED HEARTBEAT
Even if you don't set any heartbeat packets, when the Micro Snow device is on the TCP
client side, the implicit heartbeat function will be enabled. Therefore, the implicit heartbeat
function means that the device sends data, but the server cannot actually receive the heartbeat
data. Therefore, it cannot play the first function of the heartbeat packet, that is, the server
detects whether the device is active or not; but because the device actually sends data, it can
play the second function of the heartbeat packet, that is, the device detects the TCP connection
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