| 摘要 |
PURPOSE:To provide addition and subtraction functions without increasing the number of keys by letting the keys of a key matrix having tare key, data hold keys, etc. also serve as addition and subtraction keys. CONSTITUTION:A microcomputer 1 is constituted by a CPU 2, RAM 3, ROM 4 and its input side is connected with number keys 5 for setting unit prices, a tare key 6 which sets the weight placed on a weighing pan as a tare amount and also becomes an addition instruction means, a set key 7 which sets the tare amount by increasing the set by each 1 minimum graduation and also becomes a subtraction instruction means, a data hold key 8 for price fixing which becomes a function change-over means, etc. As the data holding key is pushed, only the price display is left and the tare key 6 and set key 7 are switched respectively to addition-subtraction instruction functions and from the state of the weighing functions, they are changed over to the station of the addition-subtraction functions. |
