The Additel ADT 773-LLP Low Pressure Controller is a high-performance automatic pneumatic pressure controller and generator specifically designed for precise low and differential pressure calibration. With integrated pressure generation, two interchangeable ADT151 differential pressure modules and excellent pressure control performance, the ADT 773-LLP provides an advanced solution for calibration laboratories, HVAC applications, cleanroom instrumentation, filter monitoring, airflow measurement and sensitive differential pressure sensors.
The ADT 773-LLP covers pressure ranges up to:
-380 to +400 inH₂O
or approximately:
-0.95 to +1 bar
depending on the installed ADT151 pressure module.
At the opposite end of the range, suitable ADT151 modules allow the system to work with extremely small differential pressures.
The ADT 773-LLP is specifically classified by Additel for:
Low Differential Pressure
applications.
A major advantage of the ADT 773-LLP is its integrated pneumatic pressure pump. Unlike conventional laboratory pressure controllers requiring a separate external pressure source, the ADT 773-LLP automatically generates and regulates pressure using its built-in pneumatic system.
Pressure control stability is specified as:
0.003 % FS or 0.05 Pa, whichever is greater
with a pressure control response time of:
<10 seconds
under Additel’s specified test conditions.
Depending on the installed ADT151 module, pressure measurement accuracy is available down to:
0.01 % FS
while the smallest differential pressure modules have dedicated specifications appropriate to their particularly sensitive measuring ranges.
For professional calibration and metrological traceability of differential pressure instruments, transmitters, sensors, gauges and reference pressure equipment, visit the europascal calibration service.
Your Benefits at a Glance
The Additel ADT 773-LLP Low Pressure Controller provides:
- Automatic low differential pressure generation
- Integrated pneumatic pressure pump
- Pressure capability from approximately -0.95 to +1 bar
- Maximum range from -380 to +400 inH₂O
- Very low differential pressure measurement capability
- Accuracy down to 0.01 % FS depending on ADT151 module
- Special accuracy specifications for the smallest DP modules
- Control stability of 0.003 % FS or 0.05 Pa, whichever is greater
- Pressure control response time <10 seconds
- Two interchangeable ADT151 pressure module bays
- High-pressure bay from DP40 to DP400
- Low-pressure bay from DP2 to DP400
- Automatic or fixed range selection
- Fast, Standard and Custom control modes
- Maximum overshoot <1 % FS
- Maximum external load volume of 500 ml
- 6 mm Festo pressure ports
- Integrated 40–100 µm pressure port filters
- Optional Contamination Prevention System
- Optional barometric reference module
- Three external valve control channels
- Pressure switch testing
- 7-inch capacitive touchscreen
- RS232, USB and LAN communication
- SCPI command support
- Suitable for automated calibration systems
Designed for Low Differential Pressure
The Additel ADT 773-LLP is specifically optimized for:
Low Differential Pressure
measurement and control.
Differential pressure is defined as:
Δp = pHigh – pLow
In many industrial and laboratory applications, this pressure difference can be extremely small.
Examples include:
- Cleanroom pressure
- Air filter pressure drop
- Ventilation pressure
- Airflow measurement
- HVAC systems
- Low-pressure transmitters
- Sensitive differential pressure sensors
These applications require not only accurate pressure measurement but also exceptionally stable and finely controlled pressure generation.
The ADT 773-LLP combines both functions in one automated benchtop system.
Pressure Range up to ±1 bar
The maximum internal module control range of the ADT 773-LLP is approximately:
-1 to +1 bar
or:
-400 to +400 inH₂O
The overall negative operating limit is specified at approximately:
-0.95 bar / -380 inH₂O
based on an atmospheric pressure of 1 bar.
This wide range means that the ADT 773-LLP can cover both very sensitive low-pressure applications and substantially higher differential pressure ranges using the appropriate ADT151 module.
Extremely Low Differential Pressure Ranges
One of the most important advantages of the ADT 773-LLP is its compatibility with very low-range ADT151 modules.
The low-pressure module bay supports modules from:
DP2 through DP400
while the high-pressure bay supports:
DP40 through DP400
This allows the controller to be configured with one module optimized for very small differential pressures and a second module for a higher pressure range.
The modular architecture is particularly useful for calibration laboratories working with instruments having widely different differential pressure ranges.
Two Interchangeable ADT151 Module Bays
The ADT 773-LLP contains:
two interchangeable internal pressure module bays
for Additel ADT151 differential pressure modules.
The two bays provide a flexible multi-range configuration.
High-Pressure Bay
Supported modules:
DP40 to DP400
Low-Pressure Bay
Supported modules:
DP2 to DP400
A suitable combination of modules allows the ADT 773-LLP to provide excellent measurement capability across a broad low-pressure range.
Automatic Range Selection
The ADT 773-LLP supports:
Fixed
and:
Auto
range switching.
When two different ADT151 modules are installed, automatic range selection can select the appropriate reference range according to the requested pressure.
This is especially useful when a calibration procedure contains pressure points spanning significantly different ranges.
Why Module Selection Matters
Consider two differential pressure instruments with ranges of:
±5 mbar
and:
±500 mbar
Using only a high-range reference sensor for both devices would not necessarily provide optimum measurement capability at ±5 mbar.
The interchangeable ADT151 module concept allows a low-range module to be selected for the smaller device.
This can significantly improve the relationship between the reference capability and the device under test.
For professional calibration work, the selected ADT151 module should therefore always be considered together with the required calibration range and target measurement uncertainty.
Pressure Measurement Accuracy
The exact accuracy specification depends on the installed ADT151 module.
For suitable ADT151 differential pressure modules, accuracy options include:
0.01 % FS
or:
0.02 % FS
For the particularly small pressure ranges, Additel specifies:
DP2 and DP5: 0.05 % FS
and:
DP10: 0.02 % FS
These dedicated specifications are important because extremely small differential pressure ranges require different metrological considerations from higher pressure ranges.
The selected module and its exact specification should therefore be considered when determining the achievable calibration capability.
Precision
Depending on the selected ADT151 module, precision specifications include:
0.004 % FS
or:
0.007 % FS
For the smallest modules, Additel specifies dedicated values:
DP2 and DP5: 0.02 % FS
DP10: 0.01 % FS
Additel defines precision as including contributions such as linearity, hysteresis, repeatability, resolution and temperature compensation.
Accuracy additionally considers reference standard measurement uncertainty and annual drift.
Excellent Pressure Control Stability
For the Additel ADT 773-LLP, control stability is specified as:
0.003 % FS or 0.05 Pa, whichever is greater
The 0.05 Pa component is especially important at very small pressure ranges.
For example, simply applying 0.003 % FS to an extremely small measuring range could result in an unrealistically small numerical value.
Additel therefore defines a minimum absolute control stability criterion.
This is particularly relevant when calibrating highly sensitive low differential pressure instruments.
Fast Pressure Control
The ADT 773-LLP provides a pressure control response time of:
<10 seconds
under Additel’s defined test conditions.
The manufacturer’s test condition uses:
50 ml external load volume
and a:
20 % pressure step
with the response time determined until the pressure reaches:
0.005 % FS stability
Fast automatic stabilization can significantly reduce calibration time when many measurement points need to be tested.
Integrated Pneumatic Pump
The ADT 773-LLP incorporates a:
built-in air pump
for automatic pressure generation.
This is a major advantage compared with conventional pressure controllers that require a separate compressed-air or nitrogen supply.
The integrated pump automatically generates the required positive or negative differential pressure and the closed-loop controller regulates it to the selected setpoint.
This provides a compact and highly automated low-pressure calibration system.
No Separate Pressure Source for Typical Applications
Because pressure generation is integrated, a typical calibration setup can be simplified to:
ADT 773-LLP → Device Under Test
Additional reference instruments, electrical measurement equipment or manifolds can be incorporated according to the calibration application.
The integrated pressure generation reduces the amount of external pneumatic equipment required on the calibration bench.
Fast, Standard and Custom Control Modes
The ADT 773-LLP provides three control modes:
Fast
Standard
and:
Custom
Fast mode is useful when calibration cycle time is important.
Standard mode provides balanced control behavior.
Custom mode allows the pressure control characteristics to be adapted to specific applications.
This can be particularly valuable for sensitive low-pressure instruments or unusual pneumatic volumes.
Maximum Overshoot <1 % FS
Additel specifies maximum pressure overshoot of:
<1 % FS
Controlled pressure approach is particularly important for sensitive low differential pressure sensors because excessive pressure can overload or potentially damage delicate sensing elements.
The automatic controller reduces the need for manual pressure adjustment and provides repeatable pressure approach behavior.
Maximum Load Volume 500 ml
The maximum external load volume is:
500 ml
The actual pressure response depends on:
- Connected volume
- Tubing length
- Tubing diameter
- Pressure range
- Requested pressure step
- Leakage
- Device under test
- Selected control mode
For sensitive low-pressure calibration, keeping the connected pneumatic volume as small as practical can improve response behavior.
6 mm Festo Pressure Connections
The ADT 773-LLP uses:
6 mm Festo
pressure connections.
These connections are suitable for the low-pressure pneumatic architecture of the controller.
Appropriate clean tubing and fittings should be used to maintain reliable pressure control.
Integrated Pressure Port Filters
All pressure ports are equipped with approximately:
40–100 µm filters
The filters help prevent particles from entering the internal pneumatic system.
Contamination protection is important for maintaining reliable operation of valves, pressure modules and control components.
Optional Contamination Prevention System
For additional protection, the ADT 773-LLP supports Additel’s optional:
Contamination Prevention System (CPS)
The CPS is particularly useful when devices under test may contain:
- Moisture
- Oil
- Particles
- Process residues
- Other contamination
Preventing contaminants from entering the controller can help protect the internal pneumatic system and reference modules.
Cleanroom Pressure Calibration
One of the most important applications for the Additel ADT 773-LLP is cleanroom differential pressure calibration.
Cleanrooms frequently operate with very small pressure differences between adjacent rooms or zones.
These pressure differences help control airflow and prevent unwanted contamination transfer.
The associated differential pressure transmitters and sensors therefore require reliable calibration at very small pressure values.
The ADT 773-LLP is specifically designed for this type of application.
HVAC Calibration
Heating, ventilation and air-conditioning systems use differential pressure measurement for numerous purposes.
Typical applications include:
- Airflow monitoring
- Duct pressure measurement
- Filter monitoring
- Fan control
- Building pressure measurement
- Room pressure measurement
The ADT 773-LLP provides automatic low-pressure generation for calibration of the associated sensors and transmitters.
Filter Monitoring
Air filters create a pressure drop between their inlet and outlet.
As contamination increases, the pressure difference generally increases.
Differential pressure transmitters are therefore widely used to monitor filter condition.
The ADT 773-LLP can automatically generate known differential pressures to verify the performance of these instruments.
Airflow Measurement
Low differential pressure is also frequently used for airflow measurement.
Examples include:
- Pitot tubes
- Venturi elements
- Flow nozzles
- Orifice plates
The pressure difference generated by these devices is related to flow velocity or volumetric flow.
Accurate calibration of the associated differential pressure instrument is therefore important for reliable flow measurement.
Differential Pressure Transmitter Calibration
A typical transmitter calibration procedure can include:
- Connect the transmitter to the ADT 773-LLP
- Zero the pressure system
- Generate the first differential pressure point
- Allow the pressure to stabilize
- Measure the transmitter output
- Repeat at increasing pressure points
- Measure decreasing pressure points
- Return to zero
The ADT 773-LLP automatically generates and regulates each reference pressure.
This reduces manual pressure adjustment and improves the efficiency of multipoint calibration.
Pressure Switch Testing
The ADT773 platform also supports testing of:
- Mechanical pressure switches
- Electronic pressure switches
The controller can automatically change pressure to determine the switching point and reset behavior.
This is useful for low-pressure switches used in HVAC, ventilation and process applications.
External Valve Control
The ADT 773 provides:
three external valve control channels
One channel can be used with the optional Contamination Prevention System.
Additional channels can control external pneumatic equipment such as:
- Vacuum pumps
- Shut-off valves
- Isolation valves
This expands the possibilities for automated calibration benches and custom test systems.
7-Inch Touchscreen
The ADT 773-LLP uses a:
7-inch capacitive color touchscreen
with a resolution of:
1280 × 800 pixels
The large display provides convenient access to pressure measurement, control and configuration functions.
This makes the system suitable for both standalone laboratory operation and automated calibration stations.
Communication and Automation
Standard communication interfaces include:
- RS232
- USB
- LAN
The ADT773 platform can also be integrated into automated measurement and calibration systems.
Remote command capability allows software to:
- Set pressure points
- Control pressure
- Read measurement values
- Configure the instrument
- Automate calibration sequences
SCPI and Modbus Support
The ADT773 platform supports remote programming interfaces including:
SCPI
and:
Modbus
This provides flexibility for integration into existing calibration software, laboratory automation systems and custom test applications.
Technical Highlights
Model: Additel ADT 773-LLP
Device type: Automatic Low Differential Pressure Controller / Generator
Pressure type: Low Differential Pressure
Maximum positive pressure: +400 inH₂O / approximately +1 bar
Maximum negative pressure: -380 inH₂O / approximately -0.95 bar
Pressure generation: Integrated air pump
Accuracy: Down to 0.01 % FS depending on module
DP2 / DP5 accuracy: 0.05 % FS
DP10 accuracy: 0.02 % FS
Precision: Down to 0.004 % FS depending on module
DP2 / DP5 precision: 0.02 % FS
DP10 precision: 0.01 % FS
Control stability: 0.003 % FS or 0.05 Pa, whichever is greater
Control response: <10 seconds
Internal module bays: 2
High-pressure bay: DP40–DP400
Low-pressure bay: DP2–DP400
Range switching: Fixed or Auto
Control modes: Fast / Standard / Custom
Maximum overshoot: <1 % FS
Maximum load volume: 500 ml
Pressure port: 6 mm Festo
Port filtration: 40–100 µm
CPS: Optional
Barometric reference: Optional
External valve control: 3 channels
Display: 7-inch capacitive touchscreen
Display resolution: 1280 × 800 pixels
Communication: RS232, USB, LAN
Remote programming: SCPI / Modbus
Technical Data
| Feature | Additel ADT 773-LLP |
|---|---|
| Device type | Low Differential Pressure Controller / Generator |
| Pressure type | Low Differential Pressure |
| Maximum positive range | +400 inH₂O / +1 bar |
| Maximum negative range | -380 inH₂O / -0.95 bar |
| Pressure generation | Built-in air pump |
| Accuracy | Down to 0.01 % FS |
| DP2 / DP5 accuracy | 0.05 % FS |
| DP10 accuracy | 0.02 % FS |
| Precision | Down to 0.004 % FS |
| DP2 / DP5 precision | 0.02 % FS |
| DP10 precision | 0.01 % FS |
| Control stability | 0.003 % FS or 0.05 Pa |
| Control response | <10 s |
| Internal modules | 2 × ADT151 |
| High-pressure bay | DP40–DP400 |
| Low-pressure bay | DP2–DP400 |
| Range selection | Fixed / Auto |
| Control modes | Fast / Standard / Custom |
| Maximum overshoot | <1 % FS |
| Maximum load volume | 500 ml |
| Pressure port | 6 mm Festo |
| Port filters | 40–100 µm |
| CPS | Optional |
| External valve channels | 3 |
| Display | 7-inch touchscreen |
| Communication | RS232 / USB / LAN |
| SCPI / Modbus | Supported |
ADT 773-LLP vs. ADT 773-D
The ADT 773 is available in two configurations optimized for different differential pressure ranges.
| Feature | ADT 773-LLP | ADT 773-D |
|---|---|---|
| Primary application | Very low differential pressure | Higher differential pressure |
| Maximum positive pressure | +1 bar | +7 bar |
| Maximum negative pressure | Approx. -0.95 bar | Module dependent |
| Lowest internal module | DP2 | DP100 |
| High-pressure bay | DP40–DP400 | DP100–DP2.8K |
| Low-pressure bay | DP2–DP400 | DP100–DP2.8K |
| Integrated pump | Yes | Yes |
| Control stability | 0.003 % FS or 0.05 Pa | <0.003 % FS |
| Control response | <10 s | <10 s |
| Pressure port | 6 mm Festo | 1/4 BSP male |
The ADT 773-LLP should therefore be selected when the primary requirement is accurate generation and control of very small differential pressures.
The ADT 773-D is the preferred configuration when substantially higher differential pressures up to 7 bar are required.
ADT 773 Series Overview
The current Additel ADT773 platform consists of two complementary configurations:
ADT 773-LLP – Low Differential Pressure
and:
ADT 773-D – Differential Pressure
Together, the platform covers applications from extremely small differential pressure ranges through differential pressures up to 7 bar.
This allows laboratories to select the controller architecture that best matches their calibration workload.
Typical Applications
The Additel ADT 773-LLP Low Pressure Controller is particularly suitable for:
- Low differential pressure calibration
- Differential pressure transmitter calibration
- Low-pressure sensor calibration
- Cleanroom pressure calibration
- HVAC calibration
- Filter monitoring
- Airflow instrumentation
- Ventilation systems
- Building automation
- Room pressure measurement
- Low-pressure switches
- Flow measurement instrumentation
- Production testing
- Automated calibration
- Quality assurance
- Research and development
Typical users include:
- Professional calibration laboratories
- ISO/IEC 17025 calibration laboratories
- HVAC calibration laboratories
- Pharmaceutical companies
- Cleanroom operators
- Building automation specialists
- Filter manufacturers
- Instrument manufacturers
- Research laboratories
- Production test facilities
Calibration and Service by europascal
Very low differential pressure calibration requires careful consideration of pressure stability, zero behavior, pneumatic connections, tubing, temperature and reference measurement capability.
Selecting an ADT151 module whose measuring range is appropriately matched to the device under test is particularly important.
The europascal calibration service provides professional calibration solutions for differential pressure controllers, pressure modules, transmitters, sensors, pressure gauges and other pressure measuring equipment.
europascal can also support customers in selecting the appropriate ADT151 module combination and accessories for the ADT 773-LLP.
Why Choose the Additel ADT 773-LLP?
The Additel ADT 773-LLP Precise Low Pressure Controller is specifically designed for automatic generation and control of sensitive low differential pressures.
Its pressure capability extends from approximately -0.95 to +1 bar, while interchangeable ADT151 modules allow the controller to be adapted to significantly smaller differential pressure ranges.
With pressure measurement accuracy down to 0.01 % FS depending on the selected module, control stability of 0.003 % FS or 0.05 Pa, whichever is greater, and pressure control response below 10 seconds, the ADT 773-LLP provides excellent performance for demanding low-pressure calibration.
Two interchangeable internal pressure modules, automatic range selection, an integrated air pump, optional contamination protection, external valve control and extensive remote communication make the ADT 773-LLP particularly suitable for professional calibration laboratories and automated test systems.
Looking for an automatic controller for sensitive low differential pressure calibration? Contact europascal for expert advice on the Additel ADT 773-LLP, suitable ADT151 modules, accessories and professional calibration services.
Further information about the Additel ADT 773 from europascal can be found here.
Professional pressure calibration services from europascal can be found here.
Manufacturer information about the Additel ADT 773 can be found on the official Additel website.
