Search the Community

Through Siemens' S7 communication, I got some byte type data, but I didn't know how to convert these data into the corresponding structure data of labview. It is well known that the bool of struct in TIA occupies one bit, but the bool of struct in labview occupies one byte. Has anyone dealt with it?

I recently posted this example code to ni.com - https://decibel.ni.com/content/docs/DOC-40315 Essentially I tried to create a completely universal (or close thereto) Cluster to Struct and Back Again set of functions. These consider packing/padding, data alignment, endian-ness, etc. I included some examples that have arrays and strings in the cluster as well as data pointers. I see this topic being fairly active here on LAVA and to a slightly lesser degree at NI.com Anyway, I don't know if the code will help anyone but I would be helped by any feedback or suggestions if anyone does try it! Cheers, -Jolt

Hello, I am trying to call a function from a dll with a pointer to a complex struct. I have tried multiple ways to represent the string in the struct (see attached typedefs), but the output clusters from the dll call always has the same values as input (i.e the dll isn't updating the output values). The ref ptr is based on an example from this link and I have attached a screenshot of my code for this case: https://decibel.ni.com/content/docs/DOC-9079 Here is how the vendor defines the struct: typedef struct { dword passkey; //password dword request; //0=readprop, 1=writeprop, 2=writerelinquish dword deviceid; //device instance dword objectid; //objectid dword propid; //property id dword arrindex; //array index dword datatype; //see simpletypes dword value; dword errorclass; dword errorcode; dword priority; //1..16 union { char sval[1500]; wchar_t wval[1500/2]; byte bval[1500]; BACnetDate dval; BACnetTime tval; datetime dtval; directaddr da; HWND listbox; bufptr buf; Range rg; bdrCOV cov; pxfer *px; }aux; } bdrbag; Here is how the vendor defines the struct in their vb example: Type bdrbag passkey As Long 'password request As Long '0=readprop, 1=writeprop, 2=writeproprelinquish deviceid As Long 'device instance ObjectID As Long 'objectid propid As Long 'property id arrindex As Long 'array index datatype As Long 'see simpletypes value As Single errorclass As Long errorcode As Long priority As Long '1..16 sval(0 To 127) As Byte 'string value End Type Thanks, Russell TYPEDEF_BACNET_bdrbag_byte_cluster.ctl TYPEDEF_BACNET_bdrbag.ctl TYPEDEF_BACNET_bdrbag_ref_ptr.ctl