Remedied from?
9400 HighLine SW V5.0
Eliminated function restriction
Using the Ethernet communication module, up to three nodes are able to communicate with the controller at the same time via three possible server channels. One or more nodes may cancel this connection at any time (e.g. the cables are disconnected), thus leaving these connections inactive. They could be disconnected from the controller to provide the corresponding server channel to other nodes. So far this was not possible and resulted in a blocked server channel. Code C01511/1...3 displays the status of the three possible server channels. Even if one of the connections had been disconnected, code C01511/1...3 displayed 'Connected' because the corresponding server channel had not been disconnected automatically. Now an aborted connection is disconnected automatically. A mechanism with the following pattern has been implemented: If a connection has been established and no telegram is sent from the drive for more than one minute, the drive will send a so-called 'keep alive package'. This is an ACK telegram with 0 bytes data contents whose ACK sequence number is smaller by one number than the current ACK sequence number. The reaction of the recipient is sending its own ACK telegram for confirmation. However, the recipient does not use its own ACK telegram due to the old sequence number. For the drive, though, the recipient's ACK telegram is the required confirmation of an intact connection.
If no ACK telegram is returned within one minute, the connection will be disconnected after another two minutes since it is assumed that the connection has been aborted. The server channel will then be provided to other nodes again which will be displayed in codes C01511/1...3 and C01510/1...3 correspondingly.
If the recipient has disconnected the server channel correctly, the connection will not be checked any further of course.
In terms of figures a connection will automatically be closed four minutes after it has been cancelled. The four minutes result from the following:
A keep alive package is sent every 60 seconds. 60 seconds have been specified as a time-out for waiting for a response to a keep alive package. After another 120 seconds the connection will be disconnected. Thus, if unplugged, an open server channel will be closed after 60 + 60 + 120 = 240 seconds = 4 minutes at the latest.
Published with Service Message No. 18/2009
