The CC-HR200DW model is very sensitive to sources of outside interference, which does prevent the unit from going to sleep automatically.
Sources of such fields include RR crossings, power lines, security systems, radio towers, home computers and wireless internet networks, televisions, radios, cell phones, garage door openers and invisible dog fences, high intensity discharge lighting systems, etc.
The trick is to put the computer to sleep manually when you're done using it by:
1. Use MODE 2 to pull up Mxs/Avs as the data you're viewing in the lower display.
2. With Mxs/Avs functions showing, press and hold MODE 1 and START/ENTER until computer displays SLEEP