The FXB.ta.OBV class calculates on-balance volume: addition or subtraction of current volume to/from previous volume depending on whether a candle metric (usually, the close price) has risen or fallen. It is a bar-based calculation, and requires candle data as an input. Parameters are as follows:
| Parameter | Description |
| member | Candle member to compare. Defaults to the close (c) |
Note: the absolute current value of the OBV changes depending on the starting point/length of candle history. It is therefore mostly useful as a relative measure, not as an absolute value.
