py-korad-serial

Python 3 library to interface with the Korad KA3005P and related programmable power supplies.

Overview

This provides a Python class which wraps the serial communication protocol, and works around a firmware bug or two.

The object supports the python with statement to release the serial port automatically:

from koradserial import KoradSerial

with KoradSerial('/dev/tty.usbmodemfd121') as power_supply:
    print "Model: ", power_supply.model
    print "Status: ", power_supply.status

Requirements

This library uses the pyserial and enum34 libraries.

Unit Testing

Connect a small-value resistor (approximately 100Ω) across the positive and negative outputs.

The unit tests exercise as much as I'm able given my equipment.

Class Documentation

KoradSerial Class

Constructor __init__(port, debug=False)

The constructor takes a string containing the serial device to attach to. It attempts to connect to the power supply immediately.

If debug is set to True, then print statements will detail the data sent and received.

beep Attribute

Turns the beep on or off.

Note: This functionality doesn't appear to work reliably on my units.

from koradserial import KoradSerial

with KoradSerial('/dev/tty.usbmodemfd121') as power_supply:
    . . .
    power_supply.beep.on()
    . . .
    power_supply.beep.off()

channels Attribute

This is an array of channel objects. Channel 1 is the first element of the array. Channel 2 is the second element of the array, etc.

Thus, for single-channel power supplies channels[0] will give access to Channel 1.

Each channel has the following attributes:

current Property (read/write)

Sets or reads the current for the channel as a floating-point number.

Setting the current turns the output off.

output_current Property (read-only)

Returns the output current reported by the power supply as a floating-point number. If the output is off, this may be 0.0 or None.

output_voltage Property (read-only)

Returns the output voltage reported by the power supply as a floating-point number. If the output is off, this may be 0.0 or None.

voltage Property (read/write)

Sets or reads the voltage for the channel as a floating-point number.

Setting the voltage turns the output off.

close() Method

Closes the serial port to the power supply.

is_open Property (read-only)

Indicates whether the serial port to the power supply is open.

memories Attribute

This is an array of memory settings. Memory 1 is the first element of the array. Memory 2 is the second element of the array.

Thus memories[0] will give access to Memory 1.

Each memory has the following attributes:

recall() Method

This selects the memory, which turns the output off and sets the channels' voltage and current.

save() Method

This saves the memory's settings.

Note:

Apparently to save a setting to a memory one must do the following:

• Select the memory with recall().
• Set the channels' voltage and current.
• Save the memory with save().

from koradserial import KoradSerial

with KoradSerial('/dev/tty.usbmodemfd121') as power_supply:
    channel = power_supply.channels[0]
    m1 = power_supply.memories[0]
    
    m1.recall()
    channel.voltage = 1.00
    channel.current = 0.100
    m1.save()

model Property (read-only)

Returns the power supply model information.

open() Method

Opens the serial port to the power supply.

output Attribute

Turns the output on or off.

from koradserial import KoradSerial

with KoradSerial('/dev/tty.usbmodemfd121') as power_supply:
    . . .
    power_supply.output.on()
    . . .
    power_supply.output.off()

over_current_protection Attribute

Turns the over current protection on or off.

from koradserial import KoradSerial

with KoradSerial('/dev/tty.usbmodemfd121') as power_supply:
    . . .
    power_supply.over_current_protection.on()
    . . .
    power_supply.over_current_protection.off()

over_voltage_protection Attribute

Turns the over voltage protection on or off.

from koradserial import KoradSerial

with KoradSerial('/dev/tty.usbmodemfd121') as power_supply:
    . . .
    power_supply.over_voltage_protection.on()
    . . .
    power_supply.over_voltage_protection.off()

status Property (read-only)

Returns a Status object (documentation below) containing decoded status information.

track() Method

Sets the tracking method for multi-channel power supplies.

Note: This is untested.

Status Class

beep Attribute

Indicates the beep on/off state.

Note: May not be reliable.

channel1 Attribute

Indicates Channel 1's mode.

channel2 Attribute

Indicates Channel 2's mode.

lock Attribute

Indicates the lock on/off state.

Note: May not be reliable.

output Attribute

Indicates whether the output is on or off.

raw Attribute

This contains the raw value returned by the STATUS? command.

tracking Attribute

Indicates the power supply's tracking state.

Known Issues

• Multi-channel functionality has not been tested due to lack of access to an appropriate power supply.
• There is conflicting information about the tracking values sent and received. Somebody with a multi-channel power supply will need to verify the values.