I would say yes. The item is maintaining the effect, so the target needs to be within range. It isn't a permanent duration effect originating from the device, but it is a single effect. The only way to cancel the effect, other than PeVi, would seem to be to move the device out of range and wait for sunrise/set.
One reason for doing constant as 2/day, environmental trigger, Sun, is that it means you cannot have a device with unlimited use constant effects in them. A constant effect can only affect one target at a time. (That means that the design in the first post won't work.)
This may not be entirely consistent throughout the line, because I don't think anyone has asked the question exactly this way before.