FIELD: computer engineering; miscellaneous computer systems. SUBSTANCE: brightening time requirement stored in memory unit is periodically compared with preset maximum brightening time required. Message assigning new brightening time requirement is displayed on screen when brightening time expired exceeds maximum time required and upon its replacement new brightening time requirement is entered in memory unit by means of reset key in keyboard unit. Microprocessor timer is actuated by brightening trigger control signal, brightening time requirement preset in memory unit is counted, and newly counted value is stored in memory unit. EFFECT: improved design of device, facilitated procedure. 7 cl, 2 dwg
