alicat

TCP/Serial driver and command line tool for Alicat mass flow controllers.

If you are using Analyt-MTC flow controllers, go to this repository for more info.

Example Connections

| Type | Usage | | --- | --- | | The standard DB9 cable connected directly to a computer (unix: /dev/ttyS0, windows: COM1). | Good with older computers that still have the connector. | | The cable connected to a computer through a USB converter (unix: /dev/ttyUSB0, windows: COM1). | Good for newer computers and maker boards such as Raspberry Pis. | | Multiple cables connected to one port via a splitter and Alicat's addressing (A-Z). | Good when number of ports is limited. | | Cables routed through a TCP device server (192.168.1.100:23).

Installation

pip install alicat

Usage

Command Line

For basic tasks, this driver includes a command-line interface. Read the help for more.

alicat --help

Python

This uses Python ≥3.5's async/await syntax to asynchronously communicate with an Alicat. For example:

```python import asyncio from alicat import FlowController

async def get(): async with FlowController('ip-address:port') as flowcontroller: print(await flowcontroller.get())

asyncio.run(get()) ```

If the flow controller is communicating on the specified port, this should return a dictionary of the form:

python { 'setpoint': 0.0, # Setpoint, either mass flow rate or pressure 'control_point': 'flow', # Either 'flow' or 'pressure' 'gas': 'Air', # Can be any option in `flow_controller.gases` 'mass_flow': 0.0, # Mass flow (in units specified at time of purchase) 'pressure': 25.46, # Pressure (normally in psia) 'temperature': 23.62, # Temperature (normally in C) 'total_flow': 0.0, # Optional. If totalizer function purchased, will be included 'volumetric_flow': 0.0 # Volumetric flow (in units specified at time of purchase) }

On flow controllers, you can set the flow or pressure setpoints.

python await flow_controller.set_flow_rate(1.0) await flow_controller.set_pressure(20)

Gas Type

You can set the gas type by name or by index. For more on setting by index, see the gas table in your Alicat's manual.

python await flow_controller.set_gas('N2') await flow_controller.set_gas(8)

For firmware 5v and greater, you can create and set gas mixes. Mixes can contain up to five gases and are stored in gas indices 236-255.

python await flow_controller.create_mix(mix_no=236, name="Mix1", gases={'N2': 50, 'O2': 30, 'CO2': 20}) await flow_controller.set_gas(236) await flow_controller.delete_mix(236)

PID Parameters

For flow controllers, read and write PID loop settings for device tuning.

python await flow_controller.set_pid(p=4000, i=4000, d=10, loop_type='PD2I') print(await flow_controller.get_pid()) { 'loop_type': 'PD2I', 'P': '4000', 'I': '4000', 'D': '10', }

Other Features

Additional features include override commands to increase device functionality.

python await flow_controller.lock() # Lock the front display. await flow_controller.unlock() # Unlock the front display. await flow_controller.hold() # Hold the valve in its current position. await flow_controller.cancel_hold() # Cancel the valve hold. await flow_controller.tare_volumetric() # Tare volumetric flow. await flow_controller.tare_pressure() # Tare pressure. await flow_controller.reset_totalizer() # Reset totalizer, if totalizer functionality included.

Addressing

You can have multiple controllers on the same port by using Alicat's A-Z addresses and an RS-232 splitter.

```python flowcontroller1 = FlowController(address='A') flowcontroller2 = FlowController(address='B')

await flowcontroller1.setflowrate(1.0) await flowcontroller2.setflowrate(0.5)

await flowcontroller1.close() # /dev/ttyUSB0 is still open! await flowcontroller2.close() ```

Breaking changes

0.5.0 - Support only asyncio. The last version with synchronous code was 0.4.1. - Rename address/-a to unit/-u to match Alicat's documentation - Rename -u to -ul (for --unlock)

0.4.1 Remove TCP support. Use pip install alicat==0.3.1 if needed