EPICS Signal Variants¶

BEC exposes three common EPICS-backed signal classes through ophyd_devices:

• ophyd_devices.EpicsSignal
• ophyd_devices.EpicsSignalRO
• ophyd_devices.EpicsSignalWithRBV

Use these classes when you want to expose a single EPICS process variable in BEC instead of a full motor-style device.

Which one should I use?¶

The right choice depends on whether the PV is writable and how EPICS exposes its readback:

• Choose ophyd_devices.EpicsSignal for a normal read/write signal.
• Choose ophyd_devices.EpicsSignalRO for a read-only signal that BEC should monitor but never write to.
• Choose ophyd_devices.EpicsSignalWithRBV when the EPICS record has a setpoint PV and a separate readback PV following the usual prefix and prefix_RBV pattern.

What goes into deviceConfig?¶

Each class expects a slightly different deviceConfig section in the BEC config:

• ophyd_devices.EpicsSignal: read_pv, and optionally write_pv if the write PV differs from the read PV
• ophyd_devices.EpicsSignalRO: read_pv
• ophyd_devices.EpicsSignalWithRBV: prefix