How to manage different instrument models with one driver?

Question

Hi,
I have a driver already developed for an instrument and want to incorporate another model into it. These instruments have the nearly the same instruction set except one is a subset of the other. I would like to know the standard way or the NI way of combining these drivers. Is there a way of storing global data? I'm using LabView 6.0.
Thanks in advance.

Answer 1

There are various techniques used when creating a driver that supports multiple models or models with different installed options, where there are slight functional differences between the models and options.
If there are VIs that only pertain to a specific model or option, then modify the VI prefix to associate that VI with the particular model/option. For example, a function general family driver might use "ag33xxx" as the general prefix, but VIs that only operate on the ag33250 might use the prefix "ag33250".
It sounds as if you need to remember this model/option to modify functionality within a common VI. For example, the commands might differ between two different models. To handle this situation, you store model information in the User Data V
ISA property. At initialization time, you can detect which model you are connected with and either store the model number directly or some ID to represent the model.
Both these techniques are used in the Agilent 33xxx function generator driver . You will see how User Data is set in the Initialize VI and the retrieved in the Configure Burst Modulation VI.