Read datalayer node from PLC

[David08]

Hello,

If I use the fb DL_ReadNode to read a data from the DataLayer.

How do I know the value of the Clien_Id to make it work?

Do I have to put that value? in what format?

Thanks.

[asanchez_lsa · Accepted solution]

Hi David,

I have been trying to read data between two applications (loaded in PLC) and read data from virtual axes:

As you can see I don't use clientId, but I define 'Value' input as REAL variable in other cases I get an error.

I add another question, how should I use the FBs 'DL_ReadNodeValue' and 'DL_NodeValue?

Thanks!

[Jochen_Mueller]

Some extented explantation:

The FB DL_ReadNode can be used to read every values from the datalayer, independent to the type.

Link to docu of DL_ReadNode (Here you find the description and an example.)

But the variable you connet at "Value" must fit the datalyer type. Means you have to check the type of the datalayer-node and depending on this declaring the PLC-variable. Here you see it's a "number" (float).

if you don't see it clearly 🙂 additional you have the possibility to check it at the DataLayer tree under "types". (I know it's not nice to read.)

Schema of the lim:

{ "$schema": "http://json-schema.org/draft-04/schema#", "definitions": { "motion_core_fbtypes_AxsCfgLimits" : { "type" : "object", "properties" : { "posMin" : { "type" : "number" }, "posMax" : { "type" : "number" }, "velPos" : { "type" : "number" }, "velNeg" : { "type" : "number" }, "acc" : { "type" : "number" }, "dec" : { "type" : "number" }, "jrkAcc" : { "type" : "number" }, "jrkDec" : { "type" : "number" } }, "additionalProperties" : false } }, "$ref" : "#/definitions/motion_core_fbtypes_AxsCfgLimits"}

Hope this helps.