The STA8 series is Honeywell's absolute pressure transmitter from the SmartLine ST800 family, using piezoresistive sensing with on-chip temperature compensation for low-pressure measurement in vacuum distillation and marine vacuum systems.

Why does vacuum measurement need a dedicated absolute transmitter?

A gauge transmitter in the vacuum region reads atmospheric minus process pressure, so the signal shrinks into the noise floor. The STA8 series references absolute zero directly, holding 0.03% of span accuracy above 25 mmHgA (33 mbarA) and surviving short-term full vacuum without damage — a vacuum column's operating state is a direct reading, not a difference of two larger numbers.

What does 0.01% per-year stability change over 15 years?

Ordinary absolute transmitters drift 0.1% a year and need recalibration every few months, which means costly downtime on continuous distillation and shipboard systems. The STA8 series holds 0.01% of URL stability per year for 15 years, and its 200:1 rangeability lets one unit cover both start-up rough vacuum and running vacuum, while an 80 ms response time makes vacuum fluctuations visible before they become process upsets.

• Accuracy 0.03% of span, piezoresistive with temperature compensation
• Stability 0.01% of URL per year, maintained for 15 years
• Rangeability 200:1, response time 80 ms
• Operates above 25 mmHgA, safe under full vacuum
• 4–20 mA HART output, 10.8–42.4 Vdc supply

Against a gauge transmitter with atmospheric correction, the STA8 series measures absolute pressure directly — the reason a vacuum column gets a number, not an inference.