PURPOSE: To reduce the effect of disturbance to improve the stability of measurement, by separating force coils into the one containing a differential element and the one not containing the same and by finding a load from the current flowing to the force coil not containing the differential element.
CONSTITUTION: An output from a displacement sensor 2 which changes according to the load is amplified by a pre-amplifier 3 and divided in two. One of the divided output is inputted in the first adjusting meter 41 containing a proportional element P and an integrating element I through the intermediary of a circuit 8 which can vary gain automatically and then is transmitted to the force coil 61 through a power amplifier 51. The amplitude of the circuit 8 is increased in proportion to an input. The other output is inputted in the second adjusting meter 42 containing a differential element D and is transmitted to the force coil 62 through the intermediary of a power amplifier 52. Only the current i of the force coil 61 is taken out as the output of the balance. Minute fluctuations caused by the disturbance such as a wind and vibrations are damped by the force coil 62. By this constitution, the effect of the disturbance is avoided without losing the responsiveness to an input, whereby the stability of an indication is improved.
MIYAKE TOSHIYUKI
KAWAMOTO AKIRA
NAGAOKA TADASHI
