Flow Controller#

Using InstroFlowController for gas flow controllers

Warning

This Instrument category is new and is currently available only in the Unstable package

InstroFlowController provides a unified interface for gas flow controllers. This class is initialized with a vendor-specific driver (AlicatMC, …), and provides the vendor-agnostic API (get_flow_data, set_setpoint, select_gas, tare_flow, …).

Creating an InstroFlowController#

from instro.unstable.flowcontroller.drivers import AlicatMC
from instro.unstable.flowcontroller import InstroFlowController

fc = InstroFlowController(
    name="myFlowController",
    driver=AlicatMC("ASRL7::INSTR"),
)

A bare resource string applies the Alicat RS-232 defaults (19200 baud, carriage-return terminators). Pass a VisaConfig from instro.lib.transports.visa instead to override them, and device_id to address a unit other than "A".

Supported Vendors#

Alicat MC
AlicatMC

If your vendor or model is not listed, see Custom Driver Development, or open a Driver Request issue on GitHub.

Example#

More examples found in Examples

Details#

The following presents details about the InstroFlowController. Specific driver details can be found on their pages.

Driver Composition#

An InstroFlowController is built from a concrete driver:

InstroFlowController(name="FlowController", driver=AlicatMC("ASRL7::INSTR"))

  • The vendor driver (e.g. AlicatMC) owns the connection setup and vendor-specific command mapping.

  • InstroFlowController owns the category-level workflow: measurements, commands, publishers, the background daemon.

Lifecycle#

The typical InstroFlowController workflow:

  1. Construct: instantiate the vendor driver and pass it to InstroFlowController.

  2. open(): establishes the VISA connection.

  3. Configure and measure: select gas, set flow setpoint, tare flow (optional), and read flow data.

  4. start(): begins a periodic background daemon. (Optional) By default this calls get_flow_data periodically.

  5. stop(): ends the background daemon (if started).

  6. close(): disconnects from hardware.

Custom Driver Development#

For more information on writing a custom driver, see Custom Driver Development.