Leaderboard

That's actually covered in that document. Any child references of the front panel are "static" references. When the VI server was pretty new (around LabVIEW 5.1) those were in fact dynamic references that had to always be explicitedly closed. However in a later version of LabVIEW that was changed for performance reasons. If you attempt to close such a reference the Close Reference node is in fact simply a NoOp. This is documented and some people like to go to great lengths to make sure to always know exactly which references need to be closed and which not, in order to not use the Close Reference node unneccessarily but my personal opinion is that this is a pretty useless case of spending your time and energy and simply always using the Close Reference node anyways is the most quick and simple solution. One way to reliably detect if a returned refnum is static or dynamic is to place the node that produces the refnum into a loop that executes at least twice and typecast the refnum into an int32. If the numeric value stays the same then it is a static refnum, otherwise it is dynamic and needs to be closed explicitedly in order to avoid unneccessary resource hogging of the system.

One reason why EtherCAT slave support isn't trivial is that you need to license it from the EtherCAT consortium. EtherCAT masters are pretty trivial to do with standard network interfaces and a little low level programming but EtherCAT slave interfaces require special circuitry in the Ethernet hardware to work properly. One way to fairly easily incorporate EtherCAT slave functionality into a device is to buy the specific EtherCAT silicon chips from Beckhoff and others which also include the license to use that standard. However those chips are designed to be used in devices, not controllers so there is no trivial way of having them be used as generic Ethernet interfaces. That makes it pretty hard to support EtherCAT slave functionaility on a controller device that might also need general Ethernet connectivity, unless you add a specific EtherCAT slave port in addition to the generic Ethernet interface, which is a pretty high additional cost for something that is seldom used by the majority of the users of such PC type controllers.