| 摘要 |
PURPOSE:To improve accuracy by using an A/D converter, wherein a reference voltage generator is provided and which can be operated with respect to positive and negative inputs, and imparting bias voltage to a load cell. CONSTITUTION:The load cell 2 outputs a load cell output Ei from contact points (a) and (b) of resistors 201-204, whose resistances are changed by the strain of a load receiving part, while the load cell 2 is connected to a DC amplifier 3. The output of the DC amplifier 3 is outputted to the A/D converter 7 including the reference voltage generator 706. The A/D converter 7 is operated with respect to both positive and negative input voltages. Therefore a potentiometer 902 of a bias circuit 9 is adjusted so that the input voltage level to the A/D converter 7 becomes just zero, e.g. the weight of Wn/2 that is 1/2 the maximum load Wn is applied to the load cell. |
