How can I use Bessel VI as a input function of "nD Nonlinear System Solver"?

[newermagiq]

I want to use "nD Nonlinear System Solver" to solve a nonlinear equation in real-time measurement. The equation includes a Bessel function. I want to use a Bessel VI as the input function of the "nD Nonlinear System Solver". But the output of Bessel VI is a double data, the type of the input function is a string. So they are mismatched with error.

How can I do?

Thanks

[Misbahd]

Try a typecast function 

https://zone.ni.com/reference/en-XX/help/371361R-01/glang/type_cast/