caproto.ChannelByte¶

class caproto.ChannelByte(*, string_encoding=None, strip_null_terminator=True, **kwargs)[source]¶

8-bit unencoded CHAR data plus metadata which can be sent over a channel.

May be a single CHAR or an array of CHAR.

Parameters:

valueint or bytes: Initial starting data.
timestampfloat, TimeStamp, or 2-tuple, optional: Timestamp to report for the current value. Supported options include time.time()-style UNIX timestamps, raw EPICS timestamps in the form of TimeStamp or (seconds_since_epoch, nanoseconds).
max_lengthint, optional: Maximum array length of the data.
string_encodingstr, optional: Encoding to use for strings, used when serializing and deserializing data.
reported_record_typestr, optional: Though this is not a record, the channel access protocol supports querying the record type. This can be set to mimic an actual record or be set to something arbitrary. Defaults to ‘caproto’.
unitsstr, optional: Engineering units indicator, which can be retrieved over channel access.
upper_disp_limitint, optional: Upper display limit.
lower_disp_limitint, optional: Lower display limit.
upper_alarm_limitint, optional: Upper alarm limit.
upper_warning_limitint, optional: Upper warning limit.
lower_warning_limitint, optional: Lower warning limit.
lower_alarm_limitint, optional: Lower alarm limit.
upper_ctrl_limitint, optional: Upper control limit.
lower_ctrl_limitint, optional: Lower control limit.
value_atolint, optional: Archive tolerance value.
log_atolint, optional: Log tolerance value.

Methods

`auth_read`(hostname, username, data_type, *)	Get DBR data and native data, converted to a specific type
`auth_write`(hostname, username, data, ...[, ...])	Data write hook for clients.
`calculate_length`(value)	Calculate the number of elements given a value
`check_access`(hostname, username)	This always returns `AccessRights.READ\|AccessRights.WRITE`.
`is_compatible_array`(value)	Check if the provided value is a compatible array.
`post_state_change`(state, new_value)	This is called by the server when it exits its StateUpdateContext.
`pre_state_change`(state, new_value)	This is called by the server when it enters its StateUpdateContext.
`preprocess_value`(value)	Pre-process values destined for verify_value and write
`publish`(flags)	Publish data to appropriate queues matching the SubscriptionSpec.
`read`(data_type)	Read out the ChannelData as `data_type`.
`subscribe`(queue, sub_spec, sub)	Subscribe a queue for the given subscription specification.
`unsubscribe`(queue, sub_spec)	Unsubscribe a queue for the given subscription specification.
`update_fields`(value)	This is a hook for subclasses to update field instance data.
`verify_value`(data)	Verify a value prior to it being written by CA or Python
`write`(value, *[, flags, verify_value, ...])	Write data from native Python types.
`write_from_dbr`(data, data_type, metadata, *)	Write data from a provided DBR data type.
`write_metadata`([publish, units, precision, ...])	Write metadata, optionally publishing information to clients.

Attributes

`alarm`	The ChannelAlarm associated with this data
`data_type`
`default_value`
`epics_timestamp`	EPICS timestamp as (seconds, nanoseconds) since EPICS epoch.
`length`	The number of elements (length) of the current value
`lower_alarm_limit`	Read-only access to lower_alarm_limit data
`lower_ctrl_limit`	Read-only access to lower_ctrl_limit data
`lower_disp_limit`	Read-only access to lower_disp_limit data
`lower_warning_limit`	Read-only access to lower_warning_limit data
`max_length`	The maximum number of elements (length) this channel can hold
`severity`	Alarm severity
`status`	Alarm status
`timestamp`	UNIX timestamp in seconds.
`units`	Read-only access to units data
`upper_alarm_limit`	Read-only access to upper_alarm_limit data
`upper_ctrl_limit`	Read-only access to upper_ctrl_limit data
`upper_disp_limit`	Read-only access to upper_disp_limit data
`upper_warning_limit`	Read-only access to upper_warning_limit data
`value`	Read-only access to value data
`max_subscription_backlog`