Types, units and quality

Engineering types

Nodectra uses four primary value types:

• BOOLEAN
• INTEGER
• FLOAT
• STRING

Compatible numeric widening can allow Integer sources to feed Float consumers. Boolean or String values do not silently become numeric process values.

Units

Units are part of engineering compatibility. Values should use the same declared unit unless an explicit conversion object performs the transformation.

Quality

Operational values carry quality in addition to the displayed value. Typical states include:

• GOOD — current and valid;
• BAD — calculation or protocol failure;
• UNCERTAIN — value is available but cannot be trusted fully;
• STALE — value is older than its accepted freshness window;
• OFFLINE — source Runtime or device is unavailable;
• MISSING — no value has been observed.

Programs, alarms and automatic writes must evaluate quality deliberately. A fallback display value is not evidence that a physical signal is healthy.