Hi,
Find attached a small example which should help solve your question.
It's based on an example on the NI web site for TestStand.
The dll function receives two variables adds them and returns the answer back in the second parameter. Looking at the TestStand sequence, two variables are defined in the Locals Group called NumA and NumB. These are passed to the Step. This can be seen if you look at the specification of the step. ie select the step, right-mouse click and select specify module.., there you will see the link to Locals.NumA and Locals.NumB.
All you need to do is add your tds210 instrument function.
Hope this helps
Regards
Ray
Regards
Ray Farmer