Drive connect 1.18 polling

[ham1hel]

Hi, I have a question concerning the DriveConnect functionality to read external drives which i did not really find in the manual.

How often does the DriveConnect query the parameters of the added drive and how does the querying work, does it read all parameters or only changed ones?
Do we have any defined limits on the drive connect for how many drives we are able to load/read?

I'm working on a demo for a customer where we read some drive information from Sercos3 drives connected to a L65 and then a core connected on top of the L65 
Core uses NodeRed to add drives and then read information from them which basically seems to work but would like to know what technical limitations we have for this

[CodeShepherd · Accepted solution]

As the data layer does not hold any data (as it is a data broker), the DriveConnect app also does not poll or read the parameter on its own. It simply adds a representation of the them to data layer, so customer is able to access these with a standard read access like any other data layer node.
Reading/polling/using is done by your application. These accesses are asynchronous and are mostly depending on your network connection and load.

[ham1hel]

Thank you for the reply, i take it then that we should stick to requests from applications and not use subscriptions here.
One other question, is there a way to rename the drive nodes so we get them for example by ip address instead of serial number as with serial number if a drive is exchanged the reading will stop working without updating the request node addresses so it will then be harder to do a generic application for data collection

[CodeShepherd]

You can also use a subscription as this will start an own functionality in the data layer to internally poll values and send them to the requester. But this is the same for all nodes independent of the DriveConnect app.

Renaming of the nodes is not possible. Another possible solution is to use a asynchronous parameter read via the CXA_EthercatMaster e.g. IL_ECATCoeReadSdo . There the EtherCat address is used. See this post for an example.

[ham1hel]

Ok, thank you for the reply, it's not realy valid in my case though as we are looking at using the ctrlX as a IoT gateway and read drive info from a CML65 which has drives connected over sercos, but would be a nice feature for the future to be able to rename the data node when adding a drive with SIP