# Flow Controller

Flow controllers.

> **Warning**
>
> This Instrument category is new and is currently available only in the Unstable package.

## Instrument and Abstract Driver

| [`InstroFlowController`](https://dev.nominal.io/instro/ref/instruments/instro.unstable.flowcontroller.InstroFlowController.md#instro.unstable.flowcontroller.InstroFlowController "instro.unstable.flowcontroller.InstroFlowController") | Flow-controller instrument. |
| --- | --- |
| [`FlowControllerDriverBase`](https://dev.nominal.io/instro/ref/instruments/instro.unstable.flowcontroller.FlowControllerDriverBase.md#instro.unstable.flowcontroller.FlowControllerDriverBase "instro.unstable.flowcontroller.FlowControllerDriverBase") | Vendor flow-controller driver contract. |

## Vendor Drivers

| Vendor | Model | Description |
| --- | --- | --- |
| Alicat | [`MC-series`](https://dev.nominal.io/instro/ref/instruments/instro.unstable.flowcontroller.drivers.AlicatMC.md#instro.unstable.flowcontroller.drivers.AlicatMC "instro.unstable.flowcontroller.drivers.AlicatMC") | Alicat MC-series mass-flow controller (MC-100SCCM and related MC models). |

## Measurement keys

`FlowControllerDriverBase` defines string constants for the keys returned by `get_flow_data()` and used by the single-value properties:

| Constant | Key | Description |
| --- | --- | --- |
| `SETPOINT_KEY` | `"setpoint"` | Commanded flow setpoint |
| `MASS_FLOW_KEY` | `"mass_flow"` | Measured mass flow |
| `VOLUMETRIC_FLOW_KEY` | `"vol_flow"` | Measured volumetric flow |
| `PRESSURE_KEY` | `"pressure"` | Absolute pressure |
| `TEMPERATURE_KEY` | `"temperature"` | Gas temperature |