Digital Differential Pressure Gauge (AI-DDPG)

Digital vs Analog Magnehelic® Gauges

Traditional analog gauges rely on a mechanical pointer and dial, readable only by someone standing in front of the unit, with precision limited by how finely the dial is graduated and how accurately the eye can read the pointer position. The AI-DDPG addresses each of these limitations directly.

Precision
A digital sensor and 4-digit display reads pressure differential to a resolution of 1 Pascal or 0.1 mm.W.C., a level of precision an analog pointer and dial simply cannot match, especially at the lower end of common measurement ranges.
Reduced Reading Error
Analog gauges are subject to parallax error and interpretation differences between operators reading the same dial. A digital numeric readout removes this ambiguity entirely, what is displayed is the reading, with no room for interpretation.
Remote Data Logging via Modbus
An analog gauge only communicates its reading to whoever is physically looking at it. The AI-DDPG's RS-485 Modbus output allows pressure data to be logged, trended, and alarmed centrally through a BMS or SCADA system, supporting continuous audit trails that a pointer gauge cannot provide on its own.
Faster Fault Detection
With an integrated buzzer alarm and acknowledgement facility, the AI-DDPG can flag a setpoint violation the moment it happens, rather than relying on someone noticing a dial has drifted out of range during a routine walkthrough.

For facilities currently using analog Magnehelic® gauges, the AI-DDPG is designed as a direct digital readout replacement, fitting the same 30mm depth clean room wall mounting, while adding the precision, alarm, and BMS integration capability an analog dial cannot offer.

Features

Digital Readout Replacement for Magnehelic® Gauges
Provides the same pressure differential function as analog differential pressure gauges, with a clearer digital display.
Built-In Differential Pressure Sensor
Integrated high-speed sensor for continuous, accurate pressure differential measurement.
Unit Conversion at the Press of a Key
Switch between mm.W.C. and Pascals without external tools or recalibration.
Integrated Buzzer Alarm with Acknowledgement
Alerts on setpoint violation, with an acknowledgement facility to confirm the alert has been noted.
Analog 4-20mA Output
Enables direct connection to analog controllers or monitoring systems.
RS-485 Modbus Communication
Supports integration with BMS, SCADA, or PLC systems for centralized monitoring.
30mm Depth Enclosure
Designed to fit clean room modular wall panels without a bulky protrusion.

Applications

Laminar Air Flow Cabinets
Monitors pressure differential to confirm correct airflow direction and containment within the cabinet.
Clean Rooms
Verifies pressurisation between cleanroom zones of different classifications, supporting contamination control.
Biosafety Cabinets
Tracks pressure differential critical to maintaining containment in biological safety applications.
Air Handling Units (AHUs)
Monitors pressure drop across filters and system components to support HVAC performance verification.
Pharmaceutical Manufacturing
Maintains pressure cascades between processing zones to prevent cross-contamination during production.
Hospital Isolation Rooms & Operating Theatres
Confirms correct pressure differential for infection control in isolation wards and sterile operating environments.
Research & BSL Laboratories
Monitors containment pressure in fume hoods and biosafety level laboratories handling hazardous materials.
Filter & Duct Monitoring
Tracks pressure drop across HVAC filters and ductwork to flag clogging or maintenance needs.

Specifications

Parameter	Specification
Pressure Measuring Range	-10.0 to +10.0 mm.W.C. / -25.0 to +25.0 mm.W.C. / -50.0 to +50.0 mm.W.C. / 0.0 to +100.0 mm.W.C. / -100 to +100 Pascals / -250 to +250 Pascals / 0 to 10, 25, 50, 100, 200, 300, 500, 1000 Pascals (custom ranges available on request)
Display	Integrated 4-digit red LED 7-segment display, 0.5" high
Sensor	Integrated high-speed differential pressure sensor
Resolution	1 Pascal / 0.1 mm.W.C.
Power Supply	24 VDC
Output	Analog 4-20mA; RS-485 Modbus for BMS/SCADA/PLC integration
Enclosure Depth	30mm, suited for clean room modular wall fitment

Frequently Asked Questions

What is the AI-DDPG Digital Differential Pressure Gauge?

The AI-DDPG is a digital differential pressure gauge designed to measure and display the pressure difference between two points. It is intended for applications such as cleanrooms, laminar air flow cabinets, biosafety cabinets, and AHU systems. It provides a clear digital display along with alarm and communication options for continuous pressure monitoring.

How is the AI-DDPG different from a traditional Magnehelic® gauge?

The AI-DDPG provides a digital readout instead of an analogue dial, making the measured differential pressure easier to read and record. It is also designed as a replacement option for analogue Magnehelic®-type gauges and includes features such as a built-in sensor, buzzer alarm, 4 to 20 mA output, and RS485 Modbus communication.

Where is the AI-DDPG commonly used?

The AI-DDPG is suitable for applications where differential pressure needs to be continuously displayed, including cleanrooms, laminar air flow cabinets, biosafety cabinets, air handling units (AHUs), controlled environments, and HVAC systems. These applications use differential pressure monitoring to observe pressure conditions between two locations.

Why is digital differential pressure monitoring important in cleanrooms?

Differential pressure is an important parameter for monitoring the pressure relationship between controlled areas. A digital gauge allows operators to view the pressure reading clearly and identify deviations that may require corrective action.

Can the AI-DDPG display pressure in different units?

Yes. The AI-DDPG provides convenient unit conversion between mm.W.C. and Pascals. The unit can be changed at the press of a key, allowing users to view the measurement in the unit most suitable for their application.

Does the AI-DDPG have an alarm function?

Yes. The AI-DDPG includes an integrated buzzer alarm for process setpoint violations. It also provides an acknowledgement facility, allowing the alarm to be acknowledged by the operator.

Can the alarm setpoint be configured according to the application?

The instrument includes a setpoint violation alarm function, allowing it to be used where operators need an audible indication when the monitored differential pressure reaches the configured process limit. The exact available setpoint configuration should be selected according to the required application and model specification.

Can the AI-DDPG be connected to a BMS?

Yes. The AI-DDPG provides RS485 Modbus communication for integration with Building Management Systems (BMS), SCADA systems, and PLCs. This allows the differential pressure reading to be monitored remotely in addition to the local display.

Does the AI-DDPG provide a 4 to 20 mA output?

Yes. The AI-DDPG includes an analogue 4 to 20 mA output option for transmitting the differential pressure measurement to compatible monitoring and control systems.

What is the benefit of having both 4 to 20 mA and RS485 Modbus?

The 4 to 20 mA output provides a standard analogue signal for compatible control systems, while RS485 Modbus allows digital communication with BMS, SCADA, and PLC systems. Having these communication options provides greater flexibility when integrating the gauge into existing automation infrastructure.

Does the AI-DDPG have a built-in pressure sensor?

Yes. The AI-DDPG incorporates a built-in differential pressure sensor, eliminating the need for a separate external pressure sensing instrument.

Is the AI-DDPG suitable for cleanroom modular walls?

Yes. The instrument has a 30 mm depth and is designed for fitment in cleanroom modular walls. This makes it suitable for installations where a compact instrument profile is preferred.

Can the AI-DDPG be used for continuous pressure monitoring?

Yes. The AI-DDPG is designed as a digital differential pressure indicator for continuous monitoring applications. The local display provides an immediate pressure reading, while the alarm and communication outputs can support remote monitoring and facility automation.

How can the AI-DDPG help replace an existing analogue differential pressure gauge?

The AI-DDPG is specifically described as a replacement option for analogue Magnehelic® gauges. It provides a digital display while adding features such as alarm indication, unit conversion, 4 to 20 mA output, and RS485 Modbus communication.

Can the AI-DDPG be integrated into an existing cleanroom monitoring system?

Yes. The RS485 Modbus and 4 to 20 mA interfaces allow the gauge to be incorporated into suitable existing monitoring and automation systems. This enables the local pressure display to be supplemented with centralized monitoring through a BMS, SCADA, or PLC.

What are the main advantages of the AI-DDPG?

Clear digital pressure display, a built-in differential pressure sensor, mm.W.C. and Pascal unit conversion, an integrated buzzer alarm with acknowledgement facility, 4 to 20 mA output, RS485 Modbus communication, compact 30 mm depth, suitability for cleanroom modular wall installation, and BMS, SCADA, and PLC integration.

Who can benefit from using the AI-DDPG?

The AI-DDPG is suitable for pharmaceutical facilities, cleanroom operators, HVAC engineers, facility managers, building automation integrators, laboratories, hospitals, and industries using controlled environments where differential pressure needs to be displayed and monitored.

How do I choose the right Digital Differential Pressure Gauge?

The appropriate AI-DDPG configuration depends on the required differential pressure range, display requirements, alarm requirements, output signal, communication interface, and installation arrangement. For cleanroom applications, the required pressure range and integration requirements should be confirmed before ordering. Ace Instruments can help select the appropriate configuration for cleanrooms, laminar air flow cabinets, biosafety cabinets, AHUs, and other differential pressure monitoring applications.