Pressure · Measurement
Pressure Transmitter
An electronic sensor that turns pressure into a signal the control system can read, usually 4 to 20 mA with HART.
What it does
Feeds wellhead and flowline pressure to the RTU for alarms, shutdowns and trending, so the well is watched without a site visit.
Basics
| Types | Gauge or absolute |
| Output | 4 to 20 mA with HART, or digital |
| Hazardous areas | Explosion proof or intrinsically safe |
| Selected by | Range, wetted material, area classification |
Common failures
- Range far above the operating pressure, so resolution is poor
- Unsealed conduit entry that lets water into the housing
Troubleshooting
- Symptom
- Signal frozen at one value
- Likely cause
- Plugged impulse line or ice
- What to check
- Blow down the line, heat trace in winter
- Symptom
- Reading drifts over months
- Likely cause
- Sensor drift
- What to check
- Check against a reference and recalibrate on schedule