Q.What are the differences between "single range", "dual range" and "wide range"?
A : This is a difference in resolution.
By way of example, let's take a look at the BX3200S (single range) and BX3200H (wide range) models. The weighing capacity (how heavy a sample can be placed on the pan) of both of these balances is the same 3200 g. However, the minimum display (how much can be read by the minimum digit) of the BX3200S (single range) balance is 0.1 g, whereas it is 0.01 g, one digit further past the decimal point on the BX3200H (wide range).
Even with the same weighing capacity, smaller differences in mass can be detected on a wide-range model compared with a single-range model. The wide-range model is handy when measuring large samples at high resolution.
Next, the dual range is just being between the above wide range and single range. Let's assume that we are weighing samples with the same weighing capacity of 3200 g. On the BX3200D (dual-range) model, the minimum display will be 0.1 g when measuring a 3200 g sample. Yet, when measuring samples 600 g or below, the minimum display will be 0.01 g, one digit further past the decimal point.
The dual-range model is handy when you want almost the same degree of resolution for both large and small samples. Phrased differently, we could even describe a dual range model as two single range models in one.