Point

A Point is a single data item—one concrete quantity to be collected from, or written to, a class of devices. Its definition belongs to a Profile; its runtime value is a PointValue.

A Point answers "which quantities can be read or written on this kind of device." On an air conditioner, "indoor temperature", "set temperature", and "power state" are each a Point; their instantaneous numeric snapshots are PointValues. An analogy: a Profile is the header definition of a table, each Point is one column of it, and a PointValue is the cell a given device fills into that column at a given moment.

Two easy confusions:

• Point ≠ PointValue. A Point is the definition of a "column" (its name, type, writability, unit), and is stable; a PointValue is the value in a "cell", changing as collection proceeds. See PointValue.
• Point ≠ Command. A Point is a "quantity"; a Command is an "action" (reboot, calibrate, switch mode). Whether a Point can be written is decided by its own rwFlag—it is not, and never registered in the dc3_command command table. Reading/writing a Point goes through the PointCommand path; custom commands go through the Command path.

Key Fields

Point PointBO (table dc3_point):

Field	Type	Meaning
pointName	String	Point name (for display, e.g. "indoor temperature")
pointCode	String	Point identifier, unique within a Profile
pointTypeFlag	PointTypeEnum	Data type, see below
rwFlag	RwTypeEnum	Read/write capability, see below
unit	String	Engineering unit, e.g. ℃, kPa
baseValue	BigDecimal	Offset for linear conversion (default 0)
multiple	BigDecimal	Multiplier for linear conversion (default 1)
valueDecimal	Byte	Decimal precision, digits kept for floating-point values (default 6)
profileId	Long	Owning Profile
pointExt	PointExt	Extended config (protocol mapping, constraints, collection strategy, etc.)
enableFlag	EnableFlagEnum	Enable / disable state
tenantId	Long	Owning Tenant

Data Type pointTypeFlag

Enum	code	Meaning
STRING	string	String (default)
BYTE / SHORT / INT / LONG	byte / short / int / long	Integer
FLOAT / DOUBLE	float / double	Floating-point
BOOLEAN	boolean	Boolean

Read/Write Capability rwFlag

Enum	code	Meaning
READ_ONLY	r	Read only; can be collected, cannot be written (default)
WRITE_ONLY	w	Write only; can be written
READ_WRITE	rw	Readable and writable

Writability is decided by rwFlag, not the command table

Whether a Point can be written is determined solely by whether its rwFlag includes write capability (WRITE_ONLY or READ_WRITE). This has nothing to do with Command (dc3_command)—Point read/write is not modeled in the command table. The center validates rwFlag before a write command: a write request against a read-only Point is rejected outright.

Raw Value and Engineering Value Conversion

What a Driver reads from a device is often a raw value (a register integer, an ADC count, etc.). A Point converts it to a human-readable engineering value via a linear formula:

engineering value = raw value × multiple + baseValue   (then rounded by valueDecimal)

Example: a temperature transmitter register reads 2531, configured with multiple = 0.01, baseValue = 0, unit = ℃, valueDecimal = 2; the converted engineering value stored as a PointValue is 25.31 ℃. The defaults multiple = 1, baseValue = 0 mean the raw value equals the engineering value, with no conversion.

Relationship to Other Concepts

• A Point definition hangs under a Profile, alongside Command and Event, together describing "what capabilities this kind of device has."
• A Device belongs to one Profile and thus automatically owns all Points under it; runtime data lands as PointValues keyed by device_id + point_id.

Example

Configure three Points for an air-conditioner Profile:

pointCode	pointName	pointTypeFlag	rwFlag	unit	Note
indoor_temp	Indoor temperature	FLOAT	READ_ONLY	℃	Collect only, multiple=0.1 for conversion
set_temp	Set temperature	FLOAT	READ_WRITE	℃	Readable, and a new setpoint can be written
power	Power state	BOOLEAN	READ_WRITE	—	Read current state, write to start/stop

One air conditioner (device_id=1001) collects an engineering value of 26.5℃ for indoor_temp → it lands as one PointValue. To set it to 22℃, send one write PointCommand against set_temp; because its rwFlag=READ_WRITE, the write request passes validation and is dispatched to the driver.

A Point carries type, read/write, unit, and conversion together

A newly created Point, if not configured explicitly, defaults to type STRING, read/write READ_ONLY, baseValue=0, multiple=1, valueDecimal=6, and an empty unit. When collecting a numeric quantity, remember to change it to the matching numeric type and configure conversion, otherwise it is stored as a raw string.

Further Reading

• Profile — Point definitions hang under a Profile
• PointValue — the runtime value snapshot of a Point
• Command — action-type capability; Point read/write is not in this table
• Event — another capability type alongside Point
• Device Onboarding — how a device picks a Profile and inherits its Points