3081 Digital Differential Pressure Switch with Dual Relays, Explosion-Proof Option
3081 Electronic differential pressure switch is a digital differential pressure switch. It has two differential pressure settings. And the differential pressure switch action value is precisely adjustable. 3081 electronic differential pressure switch is a differential pressure measurement and control product that integrates differential pressure measurement, display, and control. Explosion proof optional!
Flexible adjustment and simple installation can replace most situations where liquid level switches are used. The 3081 electronic differential pressure switch is widely used in automated systems for measuring gas and liquid pressure in chemical industry, machinery, hydrology, electricity, environmental protection, etc.
Features
Electronic Differential Pressure Switch Technical Parameters
| Measurable media: | Gases and liquids (weakly corrosive) |
| Measuring range: | 0~7MPa; |
| Supply voltage: | 12~35V DC (24V DC calibration voltage) |
| Output relay capacity: | 220V AC 3A, 24V DC 5A; |
| Overload capacity: | 200-300% |
| Control output: | Relay, optocoupler, 4-20mA or 0-10V |
| Accuracy: | Better than 0.5%FS |
| Setting range: | Monitoring points can be set in the full range section to prevent fluctuations and hysteresis settings. |
| Operating temperature: | -20℃~85℃; |
| Protection level: | IP65 |
| Sampling rate: | 10 times/second (required speed can be customized according to customer needs) |
| Interface thread: | M20*1.5, G thread interface, NPT thread interface |
Differential Pressure Switch Applications
Differential pressure switches are widely used in industrial process control, automation control, air handling, liquid level control, and other fields.
Gas and Air Pressure, HVAC
In ventilation systems, when the effective airflow reaches a certain level, the differential pressure switch triggers the equipment to start, ensuring normal air quality.
Used for pre-filter, medium-efficiency filter, and high-efficiency filter alarms; fan operation and belt breakage monitoring; and positive and negative pressure monitoring in cleanrooms and kitchens;
In HVAC systems, differential pressure switches can be used to monitor the condition of air filters. As the filter gradually becomes clogged, the pressure difference across it increases. Once the set value is reached, the differential pressure switch triggers an alarm, alerting maintenance personnel to replace the filter.
Additionally, in applications requiring precise airflow control—such as hospital operating rooms or laboratory cleanrooms—differential pressure switches help maintain a positive-pressure environment indoors to prevent the entry of contaminants.
Water and Liquids (Pumps, Chillers)
The pressure differential at the pump’s inlet and outlet can indicate whether the pump is operating.
In liquid level control systems, when the liquid level reaches a preset level, the differential pressure switch triggers a switching action, causing the control valve to close to prevent overflow.
Differential pressure switches are installed on the water side of evaporators and condensers and interlocked with a PLC; the unit cannot start until water flow is established;
Hydraulics and Lubricating Oil
The differential pressure for the lubricating oil filter is fixed at 1 bar; an alarm is triggered if this value is exceeded for more than 15 seconds.
Used for differential pressure protection of refrigeration compressor lubricating oil;
Installed at the inlet of the oil return filter; when the pressure reaches the set value, the pointer enters the red zone, simultaneously activating an indicator light or buzzer.
Wiring
Relay output type (standard type)
| PIN | Markings | Features | Wire Color |
| 1 | + | Power Supply Positive Terminal (24 V DC, supply range 12–35 V DC) | Red |
| 2 | − | Power Supply Negative Terminal | Black |
| 3 | H-COM | High-Level Alarm Common Terminal | Green |
| 4 | H-OFF | High-Level Alarm Normally Open (NO) Contact | White |
| 5 | H-ON | High-Level Alarm Normally Closed (NC) Contact | Brown |
| 6 | L-COM | Low-Level Alarm Common Terminal | Blue |
| 7 | L-OFF | Low-Level Alarm Normally Open (NO) Contact | Yellow |
| 8 | L-ON | Low-Level Alarm Normally Closed (NC) Contact | Gray |
Each relay channel is a single-pole double-throw (SPDT) relay, meaning “common terminal + normally open + normally closed.” The contact rating is 220 V AC 3 A / 24 V DC 5 A.
Analog output type (4–20 mA / 0–10 V)
| output | Wiring |
| 4-20mA | Connect pin 5 (brown) to 24V (+) and pin 8 (gray) to 24V (−), forming a current loop with the power supply. |
| 0-10V | Use pin 2 (black, power supply negative) as the common terminal, and pin 8 (gray) for the voltage signal output (+). |
Calibration and Setting of Electronic Differential Pressure Switches
(1) Character Descriptions:
- SET: Entered setup mode
- S AL: Enter alarm settings
- AL: In alarm settings
- S UN: Enter unit settings
- UN: In unit settings
- PSI: PSI units
- BAR: bar units
- KP: KP units
- S AL: Enter low-level alarm settings
- S AH: Enter high-level alarm settings
- S AD: Enter accuracy settings
- S SC: Range settings
- FULL: Full-scale calibration
- OOOO: Zero calibration
- S FO: Enter basic parameter settings
- 0-H: Overpressure
(2) Entering Setup Mode:
Press and hold the SET key for two seconds, then release it to enter setup mode: the display shows “SET”;
Press the UP and DOWN keys to cycle through the display between “S AL,” “S UN,” and “SET.” Pressing the SET key enters the selected parameter to be configured.
Select “S AL,” and the display shows “AL.” Select “S UN,” and the display shows “UN.” Select “SET” to exit setup mode.
Parameter Selection:
1) S AL: In this setting category, briefly press the UP and DOWN keys; the display cycles through AL, S ALd, S ALL, and S ALH (selecting AL will exit the settings directly).
Note: Briefly press the SET key to enter the setting you wish to modify. Once in the setting mode, the flashing digit indicates the currently selectable digit for modification; briefly press the UP and DOWN keys to select the digit to be modified. Briefly press the SET key to enter the current digit value modification mode; briefly press the UP and DOWN keys to adjust the current digit value; briefly press the SET key to confirm the current digit value, and the meter will automatically return to the next parameter in the S AL setting category. Press the UP and DOWN keys briefly to continue selecting the digit to be modified. When finished, press the SET key twice to exit the current setting; the data will be saved. During the setup process, you can press and hold the SET key at any time to exit the setup mode; the original settings will remain unchanged.
2) S UN: In this settings category, briefly press the UP and DOWN keys to cycle through the display of UN, PSI, BAR, and KP. Briefly press the SET key to select a unit; the meter will automatically exit the setup mode (selecting UN will exit the setup directly).
Range and Calibration Settings:
1) Press and hold the UP and DOWN keys simultaneously for about two seconds to enter the range and calibration settings: S FO;
2) Press the UP and DOWN keys briefly; the display will cycle through S SC, FULL,OOOO, and S FO. Press the SET key briefly to select the parameter you wish to set.
Range settings are the same as alarm parameter settings; When entering zero and full-scale calibration, the display will show the current data value acquired by the AD converter. When the displayed value is an intermediate value, briefly press the UP key (or DOWN key). At this point, the displayed value will no longer update; this value is the calibration value to be saved. Then briefly press the DOWN key (or UP key) (if this step is omitted, the data will not be saved). Finally, briefly press the SET key to exit the setup mode, and the parameter will be saved.
3) In normal display mode, press and hold the Left (Right) key to display the high (low) setpoint value.
More Pressure Transmitters and Switches
The 3081 electronic differential pressure switch is a high-precision device that detects differential pressure and liquid level signals and realizes pressure differential pressure and liquid level monitoring and control. A differential pressure sensor using a diffused silicon isolation diaphragm. The differential pressure signal is amplified through a high-precision instrumentation amplifier. A built-in temperature sensor is used for temperature compensation.
The 3081 electronic differential pressure switch uses a diffused silicon differential pressure sensing chip, and the output signal is amplified and processed by a high-precision, low-temperature drift amplifier. It is sent to the A/D converter and converted into a digital signal that can be processed by the microprocessor. The processed signals control the two-way switches to measure and control the pressure difference of the control system. This intelligent differential pressure controller is flexible to use, simple to operate, easy to debug, safe and reliable.
If you need to purchase 3081 electronic differential pressure switch, or have related technical questions, please feel free to contact us!
Zhang Wei, possesses 20 years of experience as an automation instrumentation engineer, specializing in the research, design, installation, commissioning, and maintenance of automation instruments.
Face to various instrument communication protocols (such as Modbus, Profibus, etc.), with solid hardware circuit design and software programming skills (proficient in C language and PLC programming). Has extensive project experience; projects he has led and participated in have all achieved outstanding results, improving product accuracy, reducing costs, and increasing production efficiency.
Possesses excellent communication and coordination skills and a strong team spirit, enabling him to quickly respond to customer needs and provide high-quality automation instrumentation solutions.
3081 Digital Differential Pressure Switch
Differential pressure switch with 4-digit LED display, 0 to 7 MPa range, dual setpoints, 2 SPDT relays, 4-20mA or 0-10V output and explosion-proof option.
Product SKU: 3081
Product Brand: Sino-Inst
Product Currency: USD
Product Price: 190
Price Valid Until: 2029-09-09
Product In-Stock: InStock
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