pcdsdevices.signal.AvgSignal

class pcdsdevices.signal.AvgSignal(signal, averages, *, name, parent=None, **kwargs)

Signal that acts as a rolling average of another signal.

This will subscribe to a signal, and fill an internal buffer with values from SUB_VALUE. It will update its own value to be the mean of the last n accumulated values, up to the buffer size. If we haven’t filled this buffer, this will still report a mean value composed of all the values we’ve receieved so far.

Warning: this means that if we only have recieved ONE value, the mean will just be the mean of a single value!

Parameters:

• signal (Signal) – Any subclass of ophyd.signal.Signal that returns a numeric value. This signal will be subscribed to be AvgSignal to calculate the mean.

• averages (int) – The number of SUB_VALUE updates to include in the average. New values after this number is reached will begin overriding old values.

Methods

describe()

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)

The readback value

read()

Put the status of the signal into a simple dictionary format for data acquisition

Returns:

dict

read_configuration()

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

set(value, *, timeout=None, settle_time=None, **kwargs)

Set the value of the Signal and return a Status object.

Returns:

st (Status) – This status object will be finished upon return in the case of basic soft Signals

trigger()

Call that is used by bluesky prior to read()

Attributes

SUB_META = 'meta'

averages

The size of the internal buffer of values to average over.

connected

high_limit

The high, inclusive control limit for the Signal

hints

Field hints for plotting

kind

limits

The control limits (low, high), such that low <= value <= high

low_limit

The low, inclusive control limit for the Signal

metadata

A copy of the metadata dictionary associated with the signal

metadata_keys

Metadata keys that will be passed along on value subscriptions

read_access

Can the signal be read?

subscriptions: ClassVar[FrozenSet[str]] = frozenset({'meta', 'value'})

timestamp

Timestamp of the readback value

tolerance

The absolute tolerance associated with the value.

value

The signal’s value

write_access

Can the signal be written to?