The Additel ADT 761A-LLP Low Pressure Calibrator is a fully automated portable pneumatic calibration system specifically designed for precise low and differential pressure applications. With integrated pressure generation, automatic closed-loop control, interchangeable internal pressure modules and comprehensive electrical process functions, the ADT 761A-LLP provides a powerful all-in-one solution for demanding low-pressure calibration tasks.
The pressure range extends from:
-75 to +75 mbar
or:
-30 to +30 inH₂O
The ADT 761A-LLP supports:
Gauge Pressure
and:
Differential Pressure
with a specified pressure accuracy of:
0.05 % FS
and exceptional pressure control stability of:
0.003 % FS or 0.05 Pa
The instrument is specifically optimized for very low pressure applications where stable generation and precise control of small differential pressures are essential.
This makes the Additel ADT 761A-LLP ideal for calibrating differential pressure transmitters, low-pressure sensors, filter monitoring instrumentation, HVAC measurement equipment, cleanroom pressure instruments and other devices operating in the low-pressure range.
The europascal calibration service provides professional calibration solutions for low-pressure calibrators, differential pressure instruments, pressure modules, transmitters, pressure sensors and digital pressure gauges.
Your Benefits at a Glance
The Additel ADT 761A-LLP Low Pressure Calibrator provides:
- Fully automatic low-pressure generation
- Pressure range from -75 to +75 mbar
- Pressure range from -30 to +30 inH₂O
- Gauge pressure measurement
- Differential pressure measurement
- 0.05 % FS pressure accuracy
- 0.003 % FS or 0.05 Pa control stability
- Typical response time of ≤40 seconds
- Two removable internal pressure modules
- Two external pressure module connections
- Integrated electric pump
- Automatic closed-loop pressure control
- Electrical process measurement
- High-resolution mA measurement
- Voltage measurement
- mA source and simulation
- 24 V loop power
- Pressure switch testing
- HART communication
- PROFIBUS PA communication
- Automated calibration tasks
- Task documentation
- Integrated data logging
- Wi-Fi
- Bluetooth
- USB
- Ethernet
- Portable design
- Suitable for laboratory and field calibration
Automatic Low Pressure Generation from -75 to +75 mbar
The key feature of the Additel ADT 761A-LLP is its ability to automatically generate and control very low pneumatic pressures.
Its operating range extends from:
-75 to +75 mbar
which corresponds to:
-7.5 to +7.5 kPa
or approximately:
-30 to +30 inH₂O
An integrated electric pump generates the required pressure automatically.
The operator selects a pressure setpoint and the calibrator automatically:
- Generates the required pressure
- Approaches the setpoint
- Regulates the pressure
- Stabilizes the pressure
- Measures the resulting reference pressure
This eliminates much of the manual pressure adjustment normally associated with low differential pressure calibration.
Gauge and Differential Pressure
The ADT 761A-LLP supports both:
Gauge Pressure
and:
Differential Pressure
Gauge pressure is measured relative to atmospheric pressure.
Differential pressure is defined as the pressure difference between two pressure ports:
Δp = pHigh – pLow
Differential pressure measurement is especially important in applications where relatively small pressure differences must be measured accurately.
The ADT 761A-LLP is specifically designed for these demanding low-pressure applications.
Pressure Accuracy of 0.05 % FS
Additel specifies the pressure accuracy of the ADT 761A-LLP as:
0.05 % FS
FS refers to the span of the installed pressure module.
The manufacturer’s specification is a one-year accuracy including one-year stability.
The use of interchangeable internal pressure modules allows the pressure range to be better matched to the device under test.
This is particularly useful in low-pressure calibration, where selecting an appropriately sized reference range can have a significant influence on the absolute measurement uncertainty.
Exceptional Low Pressure Control Stability
The pressure control stability of the ADT 761A-LLP is specified as:
0.003 % FS or 0.05 Pa
This extremely small absolute pressure value demonstrates why the LLP configuration is specifically designed for low-pressure applications.
Stable pressure generation is especially important when calibrating sensitive differential pressure instruments because even very small pressure fluctuations can influence the displayed measurement value.
The ADT 761A-LLP automatically regulates the generated pressure to maintain stable calibration conditions.
Typical Response Time ≤40 Seconds
Additel specifies a typical response time of:
≤40 seconds
for the ADT 761A-LLP.
This specification is particularly relevant for low-pressure calibration because very small pressures can require careful regulation and stabilization.
Automatic pressure generation and control reduce the amount of manual intervention required during multipoint calibration procedures.
Two Removable Internal Pressure Modules
The Additel ADT 761A-LLP accommodates:
two removable internal pressure modules
This allows different low-pressure ranges to be combined within one calibration system.
The ability to use multiple pressure ranges is particularly valuable because pressure module accuracy is specified relative to the module span.
Using a smaller-range module for very low pressure applications can therefore improve the absolute measurement capability compared with using only the maximum ±75 mbar range.
Six-Digit Pressure Resolution
The ADT761A platform provides high-resolution pressure indication.
The LLP configuration offers:
6-digit pressure resolution
and compatible high-precision module configurations can provide additional resolution.
This is particularly valuable for very low pressure measurements, where small changes in pressure need to be clearly resolved.
Wide Selection of Pressure Units
The ADT 761A-LLP supports numerous pressure units, including:
- Pa
- hPa
- kPa
- bar
- mbar
- psi
- mmHg
- inHg
- inH₂O
- mmH₂O
- cmH₂O
- torr
Additional customizable units are also supported.
This is especially useful for HVAC and differential pressure applications, where units such as Pa, mbar and inH₂O are commonly used.
Two External Pressure Module Connections
In addition to its two internal pressure modules, the ADT761A platform provides connections for:
two external pressure modules
Compatible Additel intelligent digital pressure modules can therefore be connected for additional pressure measurement ranges.
This expands the pressure measurement capability of the calibration platform.
External pressure modules do not increase the automatic pressure-generation range of the internal LLP pressure system.
Differential Pressure Transmitter Calibration
One of the primary applications for the Additel ADT 761A-LLP is the calibration of differential pressure transmitters.
A differential pressure transmitter measures:
Δp = pHigh – pLow
and typically converts the pressure difference into an electrical output signal.
A common industrial output is:
4–20 mA
The ADT 761A-LLP can automatically generate the required differential pressure while simultaneously measuring the electrical transmitter output.
This combines pressure and electrical calibration in one workflow.
HVAC Applications
Low differential pressures are widely used in:
- Heating systems
- Ventilation systems
- Air-conditioning systems
- Building automation
- Airflow monitoring
- Filter monitoring
For example, the pressure drop across an air filter can provide information about its condition.
As contamination increases, the differential pressure across the filter generally increases.
Differential pressure transmitters used for this purpose require periodic verification and calibration.
The Additel ADT 761A-LLP provides an automatic solution for these low-pressure calibration tasks.
Cleanroom Pressure Calibration
Cleanrooms frequently use small pressure differences between adjacent rooms or zones to control airflow direction and reduce contamination transfer.
These pressure differences may be only a few pascals.
Reliable differential pressure measurement is therefore essential.
The excellent pressure control capability of the ADT 761A-LLP makes it particularly suitable for calibration of instrumentation used in:
- Pharmaceutical cleanrooms
- Laboratories
- Medical facilities
- Semiconductor production
- Controlled manufacturing environments
Filter Monitoring
Differential pressure is frequently used to monitor filters.
The pressure difference between the upstream and downstream sides of a filter changes as the filter becomes contaminated.
Typical applications include:
- HVAC filters
- Industrial air filters
- Process filters
- Cleanroom filtration
- Ventilation systems
The ADT 761A-LLP can be used to apply defined differential pressures to the corresponding transmitters and sensors.
Flow Measurement Applications
Differential pressure is also widely used for flow measurement.
A primary flow element creates a pressure difference related to the flow rate.
Examples include:
- Orifice plates
- Venturi tubes
- Flow nozzles
- Pitot tubes
The associated differential pressure transmitter converts this pressure difference into an electrical measurement signal.
The ADT 761A-LLP can be used to calibrate the differential pressure measurement component of such systems.
Electrical Process Measurement
The ADT761A platform includes comprehensive electrical process measurement functions.
Current measurement includes a:
-25 to +25 mA
range with:
0.1 µA resolution
and specified accuracy of:
±(0.008 % RD + 1.0 µA)
Additional current and voltage ranges are available.
This allows the electrical output of pressure transmitters to be measured directly during pressure calibration.
Voltage Measurement
The ADT761A provides several voltage measurement ranges extending up to:
±30 V
This makes the calibrator suitable for pressure sensors and process instrumentation with voltage outputs.
Pressure and electrical signals can therefore be evaluated using one integrated calibration system.
mA Source and Simulation
The ADT761A can also generate current signals.
Available mA source ranges include:
0 to 2.5 mA
and:
2.5 to 25 mA
This functionality expands the instrument beyond pressure measurement and supports additional process calibration applications.
24 V Loop Power
The Additel ADT 761A-LLP provides:
24 V loop power
with a maximum load of:
50 mA
This allows compatible two-wire pressure transmitters to be powered directly by the calibrator.
The ADT 761A-LLP can therefore:
- Generate the reference pressure
- Supply the transmitter
- Measure the transmitter output
using one integrated instrument.
Pressure Switch Testing
The ADT761A platform supports testing of:
- Mechanical pressure switches
- NPN switches
- PNP switches
The automatic pressure controller can approach switching points in a controlled manner.
This allows parameters such as:
- Switching pressure
- Reset pressure
- Hysteresis
to be determined.
HART Communication
The Additel ADT 761A-LLP supports:
HART communication
for compatible smart pressure transmitters.
HART communication can support functions such as:
- Device identification
- Digital process value reading
- Configuration
- Diagnostics
- Calibration workflows
This is particularly useful for modern differential pressure transmitters.
PROFIBUS PA Communication
The ADT761A platform also supports:
PROFIBUS PA
communication.
This enables compatible digital process instruments to be incorporated into calibration and maintenance workflows.
Automated Calibration Tasks
The Additel ADT 761A-LLP supports automated calibration tasks and task documentation.
A predefined calibration procedure can contain multiple increasing and decreasing pressure points.
The calibrator automatically generates and stabilizes the required pressure points and supports recording of the measurement results.
This improves repeatability and reduces manual work.
Integrated Data Logging
The ADT761A provides integrated data logging.
Measurement data can be recorded directly by the instrument for applications such as:
- Calibration documentation
- Pressure stability testing
- Long-term measurements
- Sensor evaluation
- Process monitoring
- Troubleshooting
This makes the ADT 761A-LLP useful not only as a pressure calibrator but also as a portable measurement and diagnostic system.
Modern Communication Interfaces
The Additel ADT 761A-LLP provides:
- Wi-Fi
- Bluetooth
- USB
- Ethernet
These interfaces support integration into modern digital calibration environments.
They also simplify data transfer and communication with compatible computers and peripheral equipment.
Technical Highlights
Model: Additel ADT 761A-LLP
Device type: Automatic Low Pressure Calibrator
Pressure range: -75 to +75 mbar
Pressure range: -7.5 to +7.5 kPa
Pressure range: -30 to +30 inH₂O
Pressure types: Differential and Gauge
Absolute pressure: No
Pressure accuracy: 0.05 % FS
Pressure control stability: 0.003 % FS or 0.05 Pa
Typical response time: ≤40 seconds
Internal pressure modules: 2
Internal modules: Removable
External pressure modules: 2
Pressure resolution: 6 digits
Pressure generation: Integrated electric pump
Pressure control: Fully automatic
Electrical process measurement: Yes
mA measurement: Yes
Voltage measurement: Yes
mA source: Yes
24 V loop power: Yes
Pressure switch testing: Yes
HART: Yes
PROFIBUS PA: Yes
Task documentation: Yes
Data logging: Yes
Wi-Fi: Yes
Bluetooth: Yes
USB: Yes
Ethernet: Yes
Technical Data
| Feature | Additel ADT 761A-LLP |
|---|---|
| Device type | Automatic Low Pressure Calibrator |
| Pressure range | -75 to +75 mbar |
| Pressure range | -7.5 to +7.5 kPa |
| Pressure range | -30 to +30 inH₂O |
| Pressure types | Differential / Gauge |
| Absolute pressure | No |
| Accuracy | 0.05 % FS |
| Control stability | 0.003 % FS or 0.05 Pa |
| Typical response time | ≤40 seconds |
| Internal pressure modules | 2 |
| Internal modules removable | Yes |
| External pressure modules | 2 |
| Pressure resolution | 6 digits |
| Automatic pressure generation | Yes |
| Integrated electric pump | Yes |
| Electrical process calibration | Yes |
| mA / V measurement | Yes |
| mA source | Yes |
| 24 V loop power | Yes |
| Pressure switch test | Yes |
| HART | Yes |
| PROFIBUS PA | Yes |
| Task documentation | Yes |
| Data logging | Yes |
| Communication | Wi-Fi, Bluetooth, USB, Ethernet |
ADT 761A-LLP vs. ADT 761A-D
The ADT 761A-LLP and ADT 761A-D both support gauge and differential pressure, but they are optimized for very different pressure ranges.
| Feature | ADT 761A-LLP | ADT 761A-D |
|---|---|---|
| Pressure range | -75 to +75 mbar | -0.95 to +2.5 bar |
| Pressure types | Gauge / Differential | Gauge / Differential |
| Accuracy | 0.05 % FS | 0.02 % FS |
| Control stability | 0.003 % FS or 0.05 Pa | 0.003 % FS |
| Internal modules | 2 | 2 |
| External modules | 2 | 2 |
The ADT 761A-LLP is the preferred configuration when very small differential pressures need to be generated and controlled.
The ADT 761A-D extends the positive pressure range to 2.5 bar and is therefore more suitable for higher differential and gauge pressure applications.
ADT 761A Series Overview
The ADT761A family covers a wide range of automated pneumatic calibration applications.
| Model | Pressure Range | Pressure Type |
|---|---|---|
| ADT 761A-LLP | -75 to +75 mbar | Gauge / Differential |
| ADT 761A-D | -0.95 to +2.5 bar | Gauge / Differential |
| ADT 761A-500 | -0.9 to +35 bar | Gauge / Absolute |
| ADT 761A-1K | -0.9 to +70 bar | Gauge / Absolute |
| ADT 761A-1.5K | -0.9 to +100 bar | Gauge / Absolute |
| ADT 761A-BP | 100 to 1,200 hPa | Absolute |
The ADT 761A-LLP is therefore the dedicated very-low-pressure configuration of the ADT761A family.
Typical Calibration Applications
The Additel ADT 761A-LLP Low Pressure Calibrator is particularly suitable for calibration and testing of:
- Differential pressure transmitters
- Low-pressure sensors
- Low-pressure transducers
- Differential pressure gauges
- HVAC pressure instruments
- Cleanroom pressure transmitters
- Filter monitoring sensors
- Airflow-related differential pressure instrumentation
- 4–20 mA pressure transmitters
- HART pressure transmitters
- PROFIBUS PA instruments
- Low-pressure switches
Typical users include:
- Professional calibration laboratories
- HVAC service companies
- Pharmaceutical industry
- Cleanroom operators
- Building automation
- Process industry
- Instrument manufacturers
- Environmental monitoring
- Quality assurance departments
- Mobile calibration services
Calibration and Service by europascal
Low differential pressure calibration places particularly high demands on pressure stability, suitable reference ranges and the calibration setup.
When two internal pressure modules are installed, both modules should be considered when defining the calibration scope.
The pressure connections and tubing arrangement can also influence low-pressure measurements and should be carefully selected.
The europascal calibration service provides professional calibration solutions for automatic low-pressure calibrators, differential pressure instruments, pressure modules, pressure sensors, pressure transmitters and digital pressure gauges.
europascal can also support customers in selecting suitable internal pressure modules, external pressure modules, accessories and calibration configurations.
Why Choose the Additel ADT 761A-LLP?
The Additel ADT 761A-LLP Precise Low Pressure Calibrator combines automatic pressure generation from -75 to +75 mbar, 0.05 % FS accuracy and exceptional 0.003 % FS or 0.05 Pa pressure control stability.
Its gauge and differential pressure capability makes it particularly suitable for demanding low-pressure applications such as HVAC, cleanrooms, filter monitoring and differential pressure transmitter calibration.
Two removable internal pressure modules provide flexibility for different low-pressure ranges, while two external pressure module connections further expand measurement capability.
Integrated electrical process measurement, mA sourcing, 24 V loop power, pressure switch testing, HART and PROFIBUS PA communication, automated calibration tasks and data logging make the ADT 761A-LLP a complete calibration platform for professional laboratory and field applications.
Looking for an automated solution for precise low and differential pressure calibration? Contact europascal for expert advice on the Additel ADT 761A-LLP, suitable pressure module configurations, accessories and professional calibration services.
Further information about the Additel ADT 761A series from europascal can be found here.
Further pressure calibration products from europascal can be found here.
