drive drive.constant#

Describes the entry drive.constant at version 0.1.0, registered by mime.drives.Constant.

At a glance#

  • drive drive.constant, version 0.1.0, namespace mime

  • Nodes: ConstantNode

  • The equations are on the node page: equations

  • Derivative: exact

  • Validity: none declared

What it models, and when not to use it#

A command held constant#

What it models. The value of a command, the same at every step. An apparatus’s commands map each command it takes to the drive that writes it, and a quantity written there is short for this drive: commands={"frequency": Hz(f)} is commands={"frequency": drives.Constant(Hz(f))}. The command may be a field provider’s ("frequency", "amplitude") or a chain segment’s, named <segment>.<command> ("motor.velocity").

Its node, ConstantNode, holds the value as a parameter of the graph, one exclusive edge into the command it writes, so a study can sweep the value without rebuilding the experiment. The setting value is a design setting, and it is marked as a command: its units are those of the command it is written into, checked when the experiment is planned, not by the node (whose page says its rows’ units are declared, not checked, for that reason).

When not to use it.

  • For a command that must change during a run: this one does not. A controller replaces the drive of each command it writes, and is how a command follows a law.

  • For a ramp, a pulse or a schedule: this drive is a constant and has none.

Its derivative is exact, as the generated section states: the command is the parameter, so the derivative of anything downstream with respect to the value is the derivative of the run with respect to that command.

Versions. drive.constant 0.1.0 is its first.

Settings#

Setting

Type

Default

Dimension

Role

Default’s kind

value

Annotated[Quantity, Commanded]

{"required": true}

marked Commanded

design

none

Each role and default’s kind is the entry’s setting_roles (mime.registry.SettingRole); a setting that declares none is required.

Nodes it builds#

Declared in builds; the node walk compares it with what a round-trip case builds.

Gradient status#

The derivative through this entry is exact, the derivative of what it computes.

Validity#

none declared

References#

none declared

Other declarations#

Class variable

Type

Value

moving

ClassVar[bool]

false