IAD Controller expressed concern regarding multiple ASDEX failures with subsequent automatic restarts; noting no procedures are currently available that verify the ASDEX equipment is operating within limitations.

Narrative

I was working Ground 2. I was sitting next to Local Control 3. Local Control 3's ASDEX (Airport Surface Detection Equipment; Model X) display turned itself off and went black. The ASDEX displays at all of the other positions in the Tower that I could see remained on. After 2 or 3 minutes; the Local Control 3 ASDEX display booted back up and appeared to be working. I have seen this happen at other positions in the Tower 4 or 5 times in the last year. Most people don't even say anything about it. I notified the FLM (Front Line Manager) of this event at the time of the event. I think it was placed in the facility log. I never saw maintenance check out the display. At least when the old AMASS (Airport Movement Area Safety System) system shut down it would say 'AMASS OFFLINE' Why does ASDEX not say anything? The other issue I have is that as soon as the display turns back on we use it like nothing ever happened. I would think that maintenance would have to look at the display and make sure that everything was OK before we used it. The facility needs to clearly define what the requirements are if the ASDEX display shuts down by itself then 3 min later starts up. We need to find out what is going on with this issue. We rely on this ASDEX display because we TIPH (taxi in position and hold) at IAD. We can't have this vital safety equipment shutting down by itself. Additionally; the ASDEX never notifies us that it shut down. AMASS would say 'AMASS offline'.