pcdsdevices.pim.PPMPowerMeter

class pcdsdevices.pim.PPMPowerMeter(*args, **kwargs)

Analog measurement tool for beam energy as part of the PPM assembly.

When inserted into the beam, the raw_voltage signal value should increase proportional to the beam energy. A responsivity value calibrated for each power meter in units of volts per watt is used to calculate the actual energy in the following way:

calibrated_mj = (Signal - Background) / (Responsivity * Beam_Rate)

Ophyd Device Components

Attribute	Class	Suffix	Docs	Kind	Notes
responsivity	PytmcSignal	:RESP	Responsivity in V/W, unique for every power meter.	normal
background_voltage	PytmcSignal	:BACK:VOLT	Background voltage value used to calculate pulse energy.	normal
auto_background_reset	PytmcSignal	:BACK:RESET	Set to reset auto background voltage collection.	normal
background_mode	PytmcSignal	:BACK:MODE	Can be manual or auto In manual mode, you can collect for a specified number of seconds. In auto mode, a buffer of automatically collected background voltages will be used to calculate the background voltage.	normal
manual_collect	PytmcSignal	:BACK:COLL	Start collecting background voltages for specified time.	normal
manual_in_progress	PytmcSignal	:BACK:MANUAL_COLLECTING	Manual collection currntly in progress	normal
manual_collect_time	PytmcSignal	:BACK:TIME	Time to collect background voltages for.	normal
raw_voltage	PytmcSignal	:VOLT	Raw readback from the power meter.	normal
calibrated_mj	PytmcSignal	:MJ	Calibrated absolute measurement of beam power in physics units.	normal
calibrated_uj	UnitConversionDerivedSignal			normal
wattage	PytmcSignal	:WATT	Wattage measured by power meter, equals MJ times Beamrate.	normal
thermocouple	TwinCATThermocouple		Thermocouple on the power meter holder.	normal
raw_voltage_buffer	PytmcSignal	:VOLT_BUFFER	Array of the last 1000 raw measurements. Polls faster than the EPICS updates.	omitted
calibrated_mj_buffer	PytmcSignal	:MJ_BUFFER	Array of the last 1000 fully calibrated measurements. Polls faster than the EPICS updates.	omitted
wattage_buffer	PytmcSignal	:WATT_BUFFER	Array of the last 1000 wattages. Polls faster than the EPICS updates.	omitted

Methods

configure(d: Dict[str, Any]) → Tuple[Dict[str, Any], Dict[str, Any]]

Configure the device for something during a run

This default implementation allows the user to change any of the configuration_attrs. Subclasses might override this to perform additional input validation, cleanup, etc.

Parameters:

d (dict) – The configuration dictionary. To specify the order that the changes should be made, use an OrderedDict.

Returns:

• (old, new) tuple of dictionaries

• Where old and new are pre- and post-configure configuration states.

describe() → OrderedDictType[str, Dict[str, Any]]

Provide schema and meta-data for read().

This keys in the OrderedDict this method returns must match the keys in the OrderedDict return by read().

This provides schema related information, (ex shape, dtype), the source (ex PV name), and if available, units, limits, precision etc.

Returns:

data_keys (OrderedDict) – The keys must be strings and the values must be dict-like with the event_model.event_descriptor.data_key schema.

get(**kwargs)

Get the value of all components in the device

Keyword arguments are passed onto each signal.get(). Components beginning with an underscore will not be included.

post_elog_status()

Post device status to the primary elog, if possible.

read() → OrderedDictType[str, Dict[str, Any]]

Read data from the device.

This method is expected to be as instantaneous as possible, with any substantial acquisition time taken care of in trigger().

The OrderedDict returned by this method must have identical keys (in the same order) as the OrderedDict returned by describe().

By convention, the first key in the return is the ‘primary’ key and maybe used by heuristics in bluesky.

The values in the ordered dictionary must be dict (-likes) with the keys {'value', 'timestamp'}. The 'value' may have any type, the timestamp must be a float UNIX epoch timestamp in UTC.

Returns:

data (OrderedDict) – The keys must be strings and the values must be dict-like with the keys {'value', 'timestamp'}

read_configuration() → OrderedDictType[str, Dict[str, Any]]

Dictionary mapping names to value dicts with keys: value, timestamp

To control which fields are included, change the Component kinds on the device, or modify the configuration_attrs list.

screen()

Open a screen for controlling the device.

Default behavior is the typhos screen, but this method can be overridden for more specialized screens.

classmethod set_defaults(*, connection_timeout=10.0)

Set class-wide defaults for device communications

This may be called only before any instances of Device are made.

This setting applies to the class it is called on and all its subclasses. For example,

>>> Device.set_defaults(...)

will apply to any Device subclass.

Parameters:

connection_timeout (float, optional) – Time (seconds) allocated for establishing a connection with the IOC.

Raises:

RuntimeError – If called after EpicsSignalBase has been instantiated for the first time.

status() → str

Returns a str with the current pv values for the device.

stop(*, success=False)

Stop the Device and all (instantiated) subdevices

summary()

trigger() → StatusBase

Trigger the device and return status object.

This method is responsible for implementing ‘trigger’ or ‘acquire’ functionality of this device.

If there is an appreciable time between triggering the device and it being able to be read (via the read() method) then this method is also responsible for arranging that the StatusBase object returned by this method is notified when the device is ready to be read.

If there is no delay between triggering and being readable, then this method must return a StatusBase object which is already completed.

Returns:

status (StatusBase) – StatusBase object which will be marked as complete when the device is ready to be read.

Attributes

configuration_attrs

connected

connection_timeout

hints

kind

subscriptions: ClassVar[FrozenSet[str]] = frozenset({'acq_done'})