Just an update, see pic as working in GXWorks3 & FX5 processor, however, you still cannot use the label it has to be an actual address so cannot be @My_Label has to be @Dxxx. which is not a problem. I now know that in an FX5 the actual address of the start of the D register area is 20006 I assume this never changes so could just pass the double integer value into the function.
Last edited: