When should I perform an IT test on my weight controller?

When should I do the IT test on my weight controller? I understand that when an IT Test is in progress the outputs from the load cells are interrupted. Would this cause errors in the actual weight while my application is weighing?

You are correct that when an IT Test is in progress the outputs from the load cells are interrupted. This would cause errors in the actual weight reading. The best time to complete the command for an IT Tech Test is when it is safe to do so, you have full control of the system under test, and when the process is available.

By using relays in the Integrated Technician summing junction box we can isolate individual load cells for testing purposes. This would change the weight output and could cause a gate to open or close without notice. This could be dangerous.  

The IT test may be performed with product in the vessel, empty or any point in between.  Making the environment safe is the key factor.