Patent ID: 7916117
Filing Date: 2011-03-29
Classification: G02B,G09G,H04L,H05B,Y02B

Abstract:
1. A circuit arrangement for a field unit, comprising: a power measuring device determining power existing in the field unit; a power distribution device determining if a surplus power exists for operating a screen light of a field unit screen in the field unit, wherein if a surplus power exists the power distribution device forwards the surplus power to a screen light drive device to operate the screen light, wherein if a surplus power does not exist, the power distribution device does not forward a surplus power to a screen light drive device; and a light selection device which recognizes whether lighting of the field unit screen is to take place, wherein, during a time in which the screen light is switched off by means of the light selection device, the surplus power is made available to other components, wherein the screen light drive device determines whether the surplus power is sufficient for lighting the field unit screen, to avoid failure of another function with higher priority due to screen lighting, and drives a luminous device of the field unit screen comprising the screen light, when sufficient power is available, and when, using the light selection device, it is detected that a display is to take place, wherein the screen light drive device deactivates the screen light if the surplus power is no longer sufficient for lighting.