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I need to access few Struct data declared in one FB. Under these helpful forums I found the way to declare the GET method (using REF=). But I haven't found this thing: if I want to allow just the read of a struct is there a way to do it? Using the REF= declaration then from the extern I can also change the data in the struct.
Thank you very much.
Best regards.
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Maybe I don't understand the question but can you just add a property to the functionblock and delete the "set" property. I'm not sure why "REF=" is needed so might not be understanding the question.
Thank you very much for your quick response!
Well, for not creating a property for each field of my Structs, I am using the property to access the complete struct.
E.g.
PROPERTY robotStatus : REFERENCE TO ROBOT_STATUS
Get property becomes:
robotStatus REF= l_robotStatus;
Where l_robotStatus is the local struct declared in the FB.
So even if I declare only the Get property, when from external I access the robotStatus property I can also change the data cause as far as I have understood is a REF property, so basically it's a pointer.
For safety and for reducing error situations for some structs I would like to declare the property REF= as only read.
Maybe there are other ways to access an entire struct of a FB from an external FB.
Thank you very much.
Best regards.
Last edit: raml 2020-04-22
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I guess I need to learn why you have to use REFERENCE TO ROBOT_STATUS instead of just setting the type to ROBOT_STATUS. For example the attached picture works for me.
Since I don't know why you are stuck using "REF" just a thought of something else you could do. What if you created a copy of I_robotStatus(Internal) like E_robotStatus(External) where E_robotStatus gets updated inside the FB and E_robotStatus is referenced for your property call. Then you can isolate I_robotStatus from any external calls so that if they change E_robotStatus, those changes get overwritten by the internal I_robotStatus.
Hi everybody,
I need to access few Struct data declared in one FB. Under these helpful forums I found the way to declare the GET method (using REF=). But I haven't found this thing: if I want to allow just the read of a struct is there a way to do it? Using the REF= declaration then from the extern I can also change the data in the struct.
Thank you very much.
Best regards.
Maybe I don't understand the question but can you just add a property to the functionblock and delete the "set" property. I'm not sure why "REF=" is needed so might not be understanding the question.
Last edit: Lo5tNet 2020-04-21
Thank you very much for your quick response!
Well, for not creating a property for each field of my Structs, I am using the property to access the complete struct.
E.g.
PROPERTY robotStatus : REFERENCE TO ROBOT_STATUS
Get property becomes:
robotStatus REF= l_robotStatus;
Where l_robotStatus is the local struct declared in the FB.
So even if I declare only the Get property, when from external I access the robotStatus property I can also change the data cause as far as I have understood is a REF property, so basically it's a pointer.
For safety and for reducing error situations for some structs I would like to declare the property REF= as only read.
Maybe there are other ways to access an entire struct of a FB from an external FB.
Thank you very much.
Best regards.
Last edit: raml 2020-04-22
I guess I need to learn why you have to use REFERENCE TO ROBOT_STATUS instead of just setting the type to ROBOT_STATUS. For example the attached picture works for me.
Since I don't know why you are stuck using "REF" just a thought of something else you could do. What if you created a copy of I_robotStatus(Internal) like E_robotStatus(External) where E_robotStatus gets updated inside the FB and E_robotStatus is referenced for your property call. Then you can isolate I_robotStatus from any external calls so that if they change E_robotStatus, those changes get overwritten by the internal I_robotStatus.