A combinational weighing device comprises a plurality of weighing cells and corresponding associated weighing hoppers (W.sub.1 . . . W.sub.10) and an outlet-side transfer device (5) for supplying weighed products into a package to be arranged therebelow. In conventional manner a controller (6) has an input connected with the output of the load cells and an output connected to respective drives for the closable outlets of the weighing hoppers. The drives of the outlets of the weighing hoppers are controlled in such a manner that a corresponding subcombination of several weighing hoppers is selected for forming a total amount to be supplied into a package. In order to increase the speed in cases where the individual weights of the articles differ by a sufficiently small amount the controller is designed to be switched to a second operational mode wherein the controller drives the outlets of the weighing hoppers so that each weighing hopper can be selected independently of the other weighing hoppers. This considerably increases the weighing speed.

In order to increase both the weighing accuracy and the weighing speed of a weighing apparatus, a delta.multidot.sigma analog-to-digital converter (4) having a cut-off frequency higher than that of an analog filter (3) is connected with the output of the analog filter (3). Also, in order to perform a quick drift correction of an amplifier (2), the analog filter (3) is selectively switchable so as to perform a filtering function during a weighing mode and to perform a buffering function during a correction mode correcting means (52) is provided for storing the digital signal from the delta.multidot.sigma analog-to-digital converter (4) as a drift signal (df) during the correction mode and for providing a corrected digital weight signal (d2) by subtracting the drift signal (dr) from the digital weight signal (d1) obtained from the delta.multidot.sigma-type analog-to-digital converter (4) during the weighing mode.

A combinational weighing or counting apparatus for performing a combinational calculation of measured weights or number of to-be-weighed articles M measured by a plurality of weighing hoppers 10 to determine a combination which gives the weight or number falling within a permissible range. This apparatus includes a mode selector 38 for setting the apparatus to one of weighing and discharge modes, and a mode control 39 for controlling the apparatus on the basis of one of the weighing and discharge modes which has been selected. During the weighing mode having been selected, the mode control 39 activates supply units S in operative association with selective opening and closing of the weighing hoppers 10. On the other hand, during the discharge mode having been selected, the mode control means 39 activates the supply units S while the weighing hoppers 10 are kept in fully opened position, to thereby allow the articles M remaining in the supply units S to be continuously discharged to the outside of the apparatus.

A weighing and packaging system includes a weighing apparatus (1) for weighing an article (M) and discharging an article (M) having a predetermined weight, and a packaging apparatus (200) operatively associated with the weighing apparatus (1) for receiving the article (M) discharged from the weighing apparatus (1) and packaging the article (M). An override means (85) is provided for changing an operating condition of one of the weighing and packaging apparatuses (1,200) automatically when an operating condition of the other of the weighing and packaging apparatuses (1,200) is changed.

There is provided an abnormal device determining means (CPU 51) which reads a tendency of displacement between the combination calculated weight Wc of the contents M and the post-discharge Ws measured value of the same contents M measured after such contents M have been bagged and which, based on the tendency of displacement so read, determines which one of the combination calculated value Wc and the post-discharge measured value Ws is abnormal, and a display device (54) for displaying a result of the determination. Thus, since based on the displacement tendency of the combination calculated value Wc and the post-discharge measured value Ws, which one of the combination calculated value Wc and the post-discharge measured value Ws is abnormal is determined, it can readily and easily grasped which one of the combination weighing apparatus (1) and the weight checker (300) suffers from a trouble.