Datatype problem and pointers for a .DLL

Hi I have a problem with the following code:

loadlibrary(fullpathToDll, fullpathToHeader)
handlesensor = calllib('MEDAQLib', 'CreateSensorInstance',2) % = SENSOR_ILD1700
calllib('MEDAQLib','SetParameterString',handlesensor,'IP_Interface', 'IF2004_USB');

MATLAB returns an error message in line 3 where I use calllib:

Error using calllib
Array must be numeric or logical or a pointer to one

The code works just fine in C when I use:

hSensor = CreateSenorInstance(2); // = SENSOR_ILD1700
SetParameterString(hSensor, "IP_Interface", "IF2004_USB");

I think the problem is the datatype, but everything I tried did not work. From the documentation I know that the parameters of the function SetParameterString are declared like this:

DWORD handlesensor, LPCSTR paramname, LPCSTR value

I hope you can help me with the information I provided. Thanks!

[Philip Borghesani]

What is the datatype of handlesensor? what does libfunctions -full say about CreateSenorInstance and SetParameterString? what is the c header line for these two functions? It is possible that the header is not being parsed correctly and a setdatatype on handlesensor or creating a prototype m file and fixing that may be the needed solution.

[Torsten Fenn]

If I write the code like this, handlesensor is of datatype double. I tried to convert it to ulong with a typecast, but it did not work for some reason.

CreateSensorInstance:

ulong CreateSensorInstance(ME_SENSOR)

SetParameterString:

[ERR_CODE, int8Ptr, int8Ptr] SetParameterString(ulong, int8Ptr, int8Ptr)

the c-header line is:

Private Declare Function SetParameterString     Lib "MEDAQLib.dll" (ByVal instanceHandle As Long, ByVal paramName As String, ByVal paramValue As String) 

Private Declare Function CreateSensorInstance   Lib "MEDAQLib.dll" (ByVal sensor As Long)

I think the header is parsed correctly, since it's a corporate dll.

[Lisa Petzold]

Did anyone find a solution to Torstens Problem?

I am having the same Problem as I am tyring to use the MEDAQLib from Micro-Epsilon to read a sensor from the company.

Thanks a lot!

[Petros Neoptolemou]

I do have the same issue. Did anyone find the solution, yet?

Answer 1

[Subhamoy Saha]

Yeah! I have returned with an answer this time. The error causes due to declration problem of this line

DWORD handlesensor, LPCSTR paramname, LPCSTR value

You need to follow this format

[ERR_CODE, int8Ptr, int8Ptr] SetParameterString (ulong, int8Ptr, int8Ptr)

Use the following code

loadlibrary(fullpathToDll, fullpathToHeader)
handlesensor = calllib('MEDAQLib', 'CreateSensorInstance',2) % = SENSOR_ILD1700
calllib('MEDAQLib','SetParameterString',handlesensor,int8('IP_Interface'), int8('IF2004_USB'));

Please let us know whether it worked or not.

Answer 2

[Subhamoy Saha]

I have IFD2421 sensor connected over TCP/IP and mine is working fine. You did the same thing and the error should not come. Sorry, I could not help you out but let you know soon if possible.

hSensor =calllib('MEDAQLib','CreateSensorInstance','SENSOR_IFD2421')
calllib('MEDAQLib','SetParameterString',hSensor,'IP_Interface','TCP/IP')