====Grain (GetHistory)====

When requesting history from ARDI, there are two key parameters that control the output.

The first is the **[[gethistory_method|method]]**, which is used to change how the query works.

The second is the **Grain**, which dictates the resolution of the data.

===Negative Grain===

If your grain number is //negative//, it specifies the **total number of samples to return**.

===Positive Grain===

If your grain number is //positive//, it specifies the **time in seconds between samples**. If you're requesting an hour of data, a grain of '10' or '-600' are identical.

===Grain Accuracy===

Please note that grain numbers are a //suggestion// to ARDI and its drivers - it is **not** enforced. 

The sample rate, origin and disposition of the data may result in either more or fewer samples than you request through the API, particularly if you're asking for discrete data or tables of mixed samples.