Controls › Instrumentation
Pressure
Gauge, absolute, and differential pressure measurement.
Written guides in this section
Full references, procedures, and diagnostic guides published under Pressure.
Pressure Transmitters
Gauge, absolute, and differential pressure transmitters: how they sense, how range, turndown, and accuracy specifications work, the process connection and its accessories, and the installation errors that show up as calibration problems.
8 min readUpdated Sep 5, 2026
Differential Pressure
The differential pressure transmitter as an instrument: what it measures, static and overrange ratings, the three-valve manifold and the order of operations that protects the cell, and the applications from filter head loss to membrane TMP, flow, and level.
9 min readUpdated Sep 5, 2026
Pressure Transmitter Installation
Where and how to install a pressure transmitter so it reads the process and not its own plumbing: tap location, mounting above or below the tap, isolation and bleed valves, line slope, pulsation, elevation, freeze protection, seals, vibration, and sun.
10 min readUpdated Sep 5, 2026
Impulse Lines
The tubing between the process tap and the pressure or DP transmitter, and everything that goes wrong in it: slope and routing for liquid and gas, elevation head and how to correct for it, air and condensate, blocking and manifold valves, freezing, plugging on dirty service, and the diaphragm seal alternative.
9 min readUpdated Sep 5, 2026
Pressure Calibration
What calibrating a pressure transmitter means: as-found and as-left, the five-point test and hysteresis, tolerance and the reference standard, sensor trim versus output trim versus reranging on a smart transmitter, gauge versus absolute, and intervals.
10 min readUpdated Sep 5, 2026
Topics in this area
Pressure Transmitters
Pressure Transmitters — practical reference notes for controls engineers, integrators, and technicians working with pressure.
Differential Pressure
Differential Pressure — practical reference notes for controls engineers, integrators, and technicians working with pressure.
Pressure Installation
Pressure Installation — practical reference notes for controls engineers, integrators, and technicians working with pressure.
Impulse Lines
Impulse Lines — practical reference notes for controls engineers, integrators, and technicians working with pressure.
Pressure Calibration
Pressure Calibration — practical reference notes for controls engineers, integrators, and technicians working with pressure.
Direct contact
Have a controls question?
Reach Eric Sullivan directly about anything on this site, a controls or automation topic, or one of his personal projects.
References to manufacturers, products, model numbers, software platforms, technical specifications, companies, standards organizations, or other organizations are provided for informational purposes and do not imply sponsorship, endorsement, authorization, or affiliation unless expressly stated. Manufacturer specifications must be independently verified against current manufacturer documentation.