Python reference API¶

class pypdm.PDM(address, link)¶

Class to command one Alphanov’s PDM laser sources.

MAX_DELAY = 15000¶

MAX_PULSE_WIDTH = 1275000¶

__del__()¶: For safety, disable laser when the object is deleted.

__init__(address, link)¶

Parameters:	address – PDM device address. link – Specify a string for the serial to be used (‘/dev/ttyUSBx’ or ‘COMx’), a `Link` or `PDM` instance for daisy-chained configurations.

activation¶: True when laser is enabled, False when laser is off. Call apply() to make any change effective.

apply()¶: Apply all the instructions which are in volatile memory. This makes all settings changes effectives.

current¶

Current, in mA. Please note this property is in milli-amperes and is not a percentage of the maximum current, as the official PDM documentation may state. For the percentage, see current_percentage property. Call apply() to make any change effective.

Getter:	Return diode current configuration.
Setter:	Set the new current. Raise a ValueError if current is out of bounds.

current_percentage¶: Current, in percentage of maximum. This is an alternative way of changing the current property. Call apply() to make any change effective.

current_source¶

Current source. Set to CurrentSource.NUMERIC to control the laser diode pulse current from software through the current or current_percentage attributes.

Type:	`CurrentSource`

delay¶: Delay, in ps. int. Maximum value is defined in MAX_DELAY.

delay_line_type¶: Delay line type, DelayLineType instance.

frequency¶: Frequency, in Hz. int. Read-only.

interlock_status¶: True if interlock is detected, False otherwise.

maximum_current¶: Maximum current, in mA. The getter of this property queries the PDM device once then cache the value for next accesses.

mode¶: PDM mode, Mode instance.

offset_current¶: Offset current, in mA. float.

pulse_width¶: Pulse width, in ps. int. Maximum value is defined in MAX_PULSE_WIDTH.

read_address()¶: Query laser source address.

read_protocol_version()¶

Returns:	Protocol version string, for instance ‘3.4’.

sync_source¶: Synchronization source, SyncSource instance.

temperature¶: Temperature, in degrees.

class pypdm.Link(dev)¶

Base PDM communication implementation. An instance of Link uses a serial port and can be shared by multiple PDM instances if the devices are daisy-chained.

__init__(dev)¶

Open serial device.

Parameters:	dev – Serial device path. For instance ‘/dev/ttyUSB0’ on linux, ‘COM0’ on Windows.

class pypdm.SyncSource¶

Possible PDM synchronization source.

EXTERNAL_LVDS = 1¶

EXTERNAL_TTL_LVTTL = 0¶

INTERNAL = 2¶

class pypdm.DelayLineType¶

Possible delay line types.

INTERNAL = 1¶

NONE = 0¶

class pypdm.CurrentSource¶

Possible current sources.

ANALOG = 0¶

NUMERIC = 1¶

class pypdm.Mode¶

Possible PDM mode.

CONTINUOUS = 1¶

PULSED = 0¶

class pypdm.ChecksumError¶: Thrown if a communication checksum error is detected.

class pypdm.ProtocolError¶: Thrown if an unexpected response from the device is received.

class pypdm.ProtocolVersionNotSupported(version)¶: Thrown when a PDM protocol version is not (yet) supported by the library.

class pypdm.ConnectionFailure¶

class pypdm.StatusError(status)¶: Thrown when a PDM device did not respond with ‘OK’ status to the last command.