North Devices (north_devices)

The north_devices library contains drivers and utilities for third-party devices that can be used in the North Robotics ecosystem.

Installation

Run pip install north_devices to install, or add north_devices to your requirements.txt file.

Pumps (north_devices.pumps)

Tecan Cavro (tecan_cavro)

There is a driver for the Tecan Cavro series of pumps available that uses the binary protocol to communicate with Cavro pumps on a network.

Usage

from ftdi_serial import Serial
from north_devices.pumps.tecan_cavro import TecanCavro

serial = Serial(baudrate=38400)  # Cavro pumps default to 9600
cavro = TecanCavro(serial, address=0, syringe_volume_ml=1000)

TecanCavro.home_all()  # Homes all TecanCavro pump instances

# you can perform absolute and relative moves in counts or mL, with optional velocity
cavro.move_absolute_counts(500)
cavro.move_absolute_ml(1000, velocity_counts=500)
cavro.move_relative_counts(100, velocity_counts=1000)
cavro.move_relative_ml(500)

# you can change valve positions with `move_valve`
cavro.move_valve(1)  # moves valve to port 1

# there is also a higher-level dispense method that pumps from a port to a port
cavro.dispense_ml(2000, from_port=1, to_port=2)

# you can also batch a series of commands to be sent at once
cavro.start_batch()
cavro.move_valve(1)
cavro.move_absolute_ml(500)
cavro.move_valve(2)
cavro.move_absolute_ml(0)
cavro.execute()  # you can use the `broadcast=True` flag to execute batch commands for all pumps at once

# there is also a basic loop command that can be used in a batch command
cavro.loop_start()
cavro.move_valve(1)
cavro.move_absolute_ml(500)
cavro.move_valve(2)
cavro.move_absolute_ml(0)
cavro.loop_end(10)  # loop 10 times

cavro.execute()

# multiple cavro instances can share the same serial connection if they are on a network
network = Serial(baudrate=9600)
cavro1 = TecanCavro(network, 0)
cavro2 = TecanCavro(network, 1)

# you can send batch commands to multiple cavros then execture them simultaneously
cavro1.start_batch()
cavro1.move_relative_ml(100)

cavro2.start_batch()
cavro2.move_absolute_ml(100)

TecanCavro.broadcast_execute(cavro1, cavro2)  # this will broadcast to all pumps if none given