CAP-3031-S-2-0-L Intelligent Capacitive Boiler Drum Level Gauge is manufactured using advanced patented capacitive detection technology with full-range measurement automatic compensation capability.
It enables safe, reliable, and accurate measurement and control of boiler drum water level under all operating conditions, which is crucial for ensuring safe, efficient, and energy-saving boiler operation.
The CAP-3031-S-2-0-L Intelligent Capacitive Boiler Drum Level Gauge can be widely applied to level measurement and control in various industrial drums, high-pressure heaters, low-pressure heaters, reformer furnaces, and other pressure vessels.
Description of the CAP-3031-S-2-0-L Boiler Drum Level Gauge:
It addresses issues that traditional capacitive level gauges struggle to overcome, such as significant temperature drift in the measurement system, large impact of changes in the dielectric constant of the measured medium on measurements, poor test linearity, and the need for manual on-site calibration. It enables safe, reliable, and accurate measurement and control of boiler drum water level under all operating conditions, which is crucial for ensuring safe, efficient, and energy-saving boiler operation. It can be widely applied to level measurement and control in various industrial drums, high-pressure heaters, low-pressure heaters, reformer furnaces, and other pressure vessels.
Working Principle of the CAP-3031-S-2-0-L Intelligent Capacitive Boiler Drum Level Gauge
By utilizing the relationship between changes in liquid level and the corresponding changes in capacitance on the measuring probe, the dedicated system software processes the detected capacitance changes through various compensation calculations, outputting a two-wire 4–20 mA analog current loop and four sets of SPST (NO) solid-state relay contacts proportional to the level change.
CAP-3031-S-2-0-L Intelligent Capacitive Boiler Drum Level GaugeTechnical Features 

1. Two-wire current loop with isolation between the measurement system and the current loop;
2. Accurate and continuous level measurement and control under all operating conditions (boiler start-up, shutdown, blowdown, emergency conditions, etc.);
3. Automatic compensation for changes in the dielectric constant of both liquid and vapor phases, eliminating the need for on-site calibration;
4. Automatic compensation for temperature drift in the measurement system, with temperature drift not exceeding 0.1 pF over the full temperature range;
5. Excellent electromagnetic compatibility characteristics, CE certified;
6. High temperature and pressure resistance, long service life;
7. High reliability, high accuracy, and high stability;
8. No "false water level" measurement;
9. Handheld calibrator with Chinese operating environment, easy setup, and self-diagnosis capabilities;
Technical Parameters
Operating Voltage: 30V
18V (CAP-3031-R, when output is 3.5mA)
15V (CAP-3031-S, when output is 3.5mA)
10V (when output is 22mA)
Current Loop: Two-wire 3.5mA–22mA
Fault Alarm Current: 3.5mA or 22mA, configurable
Isolation Performance: Isolation between measurement system and current loop
Explosion-Proof Rating: ExiaIICT6 (-40℃ to 70℃)
ExiaIICT1–T5 (-40℃ to 85℃)
Explosion-Proof Parameters:
Power Input:
Ui=30V, Ii=100mA, Pi=0.75W
Ci=100pF, Li=10uH
Solid-State Relay (per group):
Ui=30V, Ii=100mA, Pi=0.75W
Ci=150pF, Li=10uH
Measurement Range: 0–1270mm Max
Measurement Cycle: 0.5 seconds
Resolution: 0.02mm
Temperature Drift: ±0.5mm Max (-40℃ to 85℃)
Operating Pressure: 23MPa Max
Linearity Deviation: ±(1+0.05%FS) mm
Solid-State Relay (CAP-3031-R):
Configuration: Four groups of SPST (NO) solid-state relays
Load Voltage: 220V AC/300V DC (non-hazardous areas)
30V DC/AC (hazardous areas)
Load Current: 100mA (-40℃ to 40℃)
50mA (-40℃ to 85℃)
Alarm Mode: "Open/Close Alarm" selectable
Five independent alarm modes selectable
Delay: 1–60 seconds, independently programmable
Medium Temperature: 450℃ Max
Ambient Temperature: -40℃ to 85℃ (ExiaIICT1–T5)
-40℃ to 70℃ (ExiaIICT6)
Storage Temperature: -55℃ to 100℃
Communication Protocol: HART
Protection Rating: IP65
Electromagnetic Compatibility: CE Certified
Associated Device: CAP-3000S Handheld Operator
Typical Applications
Level measurement and control for various industrial drums, high-pressure heaters, low-pressure heaters, and other pressure vessels
Level measurement and control for reformer furnaces