From the described scenario, we conclude that you are using a CategoricalAxis and HourName is a string. So, you have 7 times "1", "2" and etc. The chard identifies them as the same category and that is why you will have 7 bars and 1 , 2 and so on.
To solve the problem you need to use DateTime value for the CategoryBinding and a DateTimeCategoricalAxis
. Respectively, you can set a LabelFormat of your preference. For Instance you can set it so that it shows only the hour of the day, and the day.