newport-motors-py 0.1.3

A python package for operating newport motors

NewportMotorsPy

This project is in no way affiliated with Newport.

Purpose

This repo contains code used to drive a large project with many newport motors. It is split into the following sub modules:

• GUI: generic GUI code using streamlit that works well with motor alignment projects
• Mocks: Mock (i.e. simulated) versions of the motors as serial objects, useful for protoyping code before motors ship
• Motors: Motor driving code for different kinds of newport motors
• USBs: usb managment code, used to scan USB ports and identify products from a particular manufacturer

Installation

This repo is not currently on pypi, so you must install it manually. To do so, clone the repo and run pip install . from the root directory.

Usage

There are a few different use cases for this package, outlined below.

Connecting a single motor

To connect a single motor, you use the relevant motor class from newport_motors.motors. For example, to connect a newport_motors.motors.Motor object, you would do the following:

from newport_motors.motors import Motor

tip_tilt = M100D("ASRL/dev/ttyUSB0::INSTR", pyvisa.ResourceManager(visa_library="@_py"))
print(tip_tilt.read_pos(tip_tilt.AXES.U))
tip_tilt.set_absolute_position(0.0, tip_tilt.AXES.U)
print(tip_tilt.read_pos(tip_tilt.AXES.U))

Simulating a single motor

To simulate a single motor, you use the relevant motor class from newport_motors.mocks. For example, to simulate a newport_motors.motors.Motor object, you would do the following:

from newport_motors.mocks import Motor
from visa_mock.base.register import register_resource

motor1_port = "MOCK0::mock1::INSTR"
register_resource(motor1_port, Mock_M100D())

Then use the motor as above, but with the port as motor1_port.

Connecting multiple motors

To connect multiple motors, you use the newport_motors.instrument module. This module contains a class called Instrument that is used to connect to multiple motors. To use it, you must first create a config file. This config file is a json file that contains a list of motors and their serial numbers. For example:

[
    {
        "name": "Spherical_1_TipTilt",
        "motor_type": "M100D",
        "motor_config": {
            "orientation": "reversed"
        },
        "serial_number": "A67BVBOJ"
    },
    {
        "name": "Spherical_2_TipTilt",
        "motor_type": "M100D",
        "motor_config": {
            "orientation": "normal"
        },
        "serial_number": "A675RRE6"
    }
]

The relevant python code then is

from newport_motors.instrument import Instrument

inst = Instrument("path/to/config.json")

Individual motors can still be accessed using inst.motors["motor_name"], but the instrument class also provides some useful methods for accessing multiple motors at once. For example, to move all motors to their home position, you can do

inst.zero_all()

Using a GUI with the motors

The newport_motors.gui module contains a generic GUI that can be used to control motors. This uses streamlit to create a web app that can be run locally. We provide small blocks to make a larger GUI so that custom projects are easy to create.

Linux connection issues

Newport devices did not natively show on ttyUSB* for me. Run the following, replacing product id if needed for different products

sudo modprobe ftdi_sio vendor=0x104d:3008 product=3008
sudo sh -c 'echo "104d 3008" > /sys/bus/usb-serial/drivers/ftdi_sio/new_id'

You can also automated this by altering ~/.bashrc:

# newport motors
if [ ! -d "/sys/bus/usb-serial/drivers/ftdi_sio" ]; then
   sudo modprobe ftdi_sio vendor=0x104d:3008 product=3008
   sudo sh -c 'echo "104d 3008" > /sys/bus/usb-serial/drivers/ftdi_sio/new_id'
fi

Since this has sudo commands, you will need to enter your password the first time you open a new terminal.

Sim mode:

Uses https://github.com/microsoft/pyvisa-mock. If you wish to use it you must install it from source (and possibly change python_requires in setup.py).

The pyvisa_mock package is defined in this package and is correctly re-exported with pip install ..