Dual Pressure Input
Measures pressure difference between high- and low-pressure process points.
Pressure Instruments
Differential Pressure Transmitter
Accurate Differential Pressure Measurement for Industrial Process Monitoring
Reliable Measurement Between Two Process Pressure Points
The FlowDo Differential Pressure Transmitter measures the pressure difference between two process inputs and converts that measurement into a usable differential-pressure value for local indication, monitoring and compatible process-control systems.
DIFFERENTIAL PRESSURE
Measurement
HIGH / LOW PRESSURE
Input
INTEGRATED DIGITAL
Display
INDUSTRIAL PROCESS
Application
Product Overview
Measure the Difference Between Two Pressure Points
Continuous differential-pressure sensing with dual process connections, integrated digital display and process output integration.
The FlowDo Differential Pressure Transmitter is designed to measure the pressure difference between a high-pressure (HP) process connection and a low-pressure (LP) process connection.
The transmitter's sensing system responds directly to the difference between these two pressure inputs (ΔP = HP − LP). The measured differential pressure is processed electronically and can be displayed locally on the illuminated front display and transmitted to compatible monitoring or control equipment.
Differential-pressure measurement is commonly used where the difference between two pressure points provides meaningful process information, such as pressure drop across filters, flow elements, heat exchangers, or closed-vessel level applications.
Selection Guidance: Final product selection should consider differential-pressure range, maximum/static process pressure, process medium, connection arrangement, wetted materials, temperature, output and installation conditions.
Key Engineering Highlights
- Dual process pressure inputs for High-Pressure (HP) and Low-Pressure (LP) sides
- Direct calculation and measurement of pressure differential (ΔP = HP − LP)
- Integrated front digital display for direct on-site differential-pressure readout
- Rugged industrial transmitter housing engineered for harsh plant environments
- Supported process signal transmission for PLC, indicator, and SCADA architectures
- Process connections and wetted materials selected around process-medium compatibility
FLOWDO • DP
0.42
bar • DIFF
Direct Reading
Digital Differential Readout
Provides immediate on-site ΔP reading for operators to verify filter condition, flow rate, or vessel head pressure instantly.
Process Unit
Differential Unit & Status Indication
Clear visual representation of measured differential pressure and operational status on the illuminated front display.
Local Controls
Front-Panel Push Buttons
On-board physical interface controls for instrument interaction and parameter review according to selected model.
Industrial Housing
Sealed Bezel Protection
Rugged circular front housing designed to shield display electronics from dust, moisture, and industrial plant conditions.
Technical Configuration
Product Specifications
Technical specifications vary according to the selected FlowDo Differential Pressure Transmitter configuration. Final values are determined by differential range, static line pressure, sensing technology, output, process connection, materials and application requirements.
Brand / Manufacturer
FlowDo Process Instruments
Product Name
FlowDo Differential Pressure Transmitter
Primary Category
Pressure Instruments
Product Type
Industrial Differential Pressure Transmitter
Measured Parameter
Differential Pressure (ΔP)
Input Configuration
Dual Process Inputs (High Pressure / Low Pressure)
Differential Pressure Range
Model / application dependent
Static / Line Pressure Rating
According to selected model
Accuracy
According to selected model
Sensing Technology
According to selected configuration
Display
Integrated Digital Display (where applicable)
Output Signal
According to selected configuration
Digital Communication
According to selected configuration
Power Supply
According to selected configuration
High-Pressure (HP) Connection
According to selected model
Low-Pressure (LP) Connection
According to selected model
Process Connection Type
According to selected configuration
Wetted Materials
According to selected configuration
Housing Material
According to selected model
Electrical Entry
According to selected configuration
Process Temperature
Model dependent
Ambient Temperature
Model dependent
Enclosure Protection
According to selected model
Primary Application
Industrial Differential Pressure Measurement & Control
Final Technical Specifications Note
Final technical specifications depend on the selected Differential Pressure Transmitter model and process application. For correct technical selection, provide your differential-pressure range, static/line pressure, process medium, process temperature, HP/LP connection arrangement, required output and communication requirements.
Product Design
Key Features
Engineered for dependable differential pressure measurement, industrial resilience, and control integration.
Continuous DP Measurement
Provides continuously changing differential-pressure information for real-time process monitoring.
Local Digital Indication
Integrated display provides convenient local process-value visibility on the shown configuration.
Smart Electronic Processing
Sensor measurement is electronically processed for indication and supported process output.
Industrial Construction
Designed for compatible industrial process-pressure applications with rugged field housing.
Process Output
Available configurations can provide a process signal for remote monitoring and control.
Automation Integration
Compatible outputs can interface with industrial PLC, controller and SCADA systems.
Application-Based Configuration
Range, connections, materials and output should be selected according to process requirements.
Operational Advantages
Reliable Differential Pressure Monitoring
Key operational benefits delivered by FlowDo Differential Pressure Transmitters across industrial systems.
Direct Pressure-Difference Measurement
Measures the difference between two process points directly at the sensing cell.
Local Visibility
Integrated display provides on-site value visibility on the applicable configuration.
Remote Monitoring
Supported outputs allow differential-pressure information to be transmitted to control equipment.
Process Insight
Pressure difference can be used to understand changes across compatible process equipment.
Automation Integration
Compatible configurations can integrate with industrial control systems and indicators.
Configurable Installation
Range, connection arrangement and process-contact materials can be selected according to available FlowDo configurations.
Process Interface
High-Pressure and Low-Pressure Connections
Understanding the role of dual process pressure inputs on differential-pressure instrumentation.
Dual Process Port Architecture
PROCESS POINT A
Higher Process Pressure
[ H / HP ]
↓ ΔP = HP − LP ↑
PROCESS POINT B
Lower Process Pressure
[ L / LP ]
Understanding Port Roles
- H / HP: High-pressure input connected to the process point with higher pressure.
- L / LP: Low-pressure input connected to the process point with lower pressure.
Important Connection Notice: Correct HP/LP connection is required for the intended differential-pressure measurement direction. Always verify port markings and engineering drawings for your specific model before connecting process impulse piping.
Engineering Concept
Differential Pressure Is Not the Same as Line Pressure
Distinguishing between the measured differential span and the background static line pressure.
*Conceptual example only — not a product specification.
Differential Pressure
Measured Difference (ΔP)
A DP transmitter measures the net difference between HP and LP (HP − LP). This span is often relatively small (e.g. 0.2 bar across a clean filter).
Static / Line Pressure
Common Process Pressure
Both process inputs may simultaneously be exposed to a high common process pressure (e.g. 10 bar line pressure). The sensor housing must withstand this static pressure safely.
Selection Engineering
Dual Rating Requirement
The selected transmitter must be suitable for both the required differential-pressure range and the maximum process/static pressure conditions of the piping system.
Measurement Calibration
Understanding Zero Differential Pressure
How the differential pressure transmitter behaves under balanced vs. unbalanced process inputs.
Zero Differential (ΔP = 0)
HP Input = 5.0 bar
LP Input = 5.0 bar
ΔP = 0.0 bar (Zero Differential)
When pressure at both ports is equal, the net mechanical force on the sensing diaphragm is balanced, yielding a zero differential reading.
Conceptual example only.Differential State (ΔP > 0)
HP Input = 5.5 bar
LP Input = 5.0 bar
ΔP = 0.5 bar (Measured Differential)
When process resistance causes upstream pressure to exceed downstream pressure, the transmitter accurately senses and outputs the 0.5 bar difference.
Conceptual example only.Practical Applications
Industrial Differential Pressure Applications
Common industrial monitoring scenarios utilizing differential pressure measurement.
Application 01
Monitor Pressure Drop Across a Filter
BEFORE (HP)
[ FILTER ]
AFTER (LP)
As a filter accumulates particulate or debris, the pressure difference between the upstream (HP) and downstream (LP) sides increases. Differential-pressure measurement provides vital information about filter clogging and maintenance timing.
Application 02
Differential Pressure for Flow Measurement
FLOW ──►
[ PRIMARY ELEMENT ]
──► FLOW
In DP flow systems, a restriction (such as an orifice plate, Venturi, or flow nozzle) creates a differential pressure proportional to flow rate. The DP transmitter measures ΔP; flow calculation depends on the primary element, process conditions and configured automation system.
Application 03
Closed Vessel Level Measurement
HP: Liquid Bottom
↔
LP: Vapor Space
In pressurized closed vessels, the LP port connects to the vapor space while the HP port connects to the liquid bottom. This cancels out vessel head pressure, measuring the hydrostatic head of the liquid column.
Application 04
Process Equipment & Heat Exchangers
UPSTREAM (HP)
[ HEAT EXCHANGER ]
DOWNSTREAM (LP)
Continuous monitoring of pressure drop across heat exchangers, reactor beds, and piping restrictions helps detect scaling, fouling, or internal flow blockages before plant efficiency degrades.
Process Connection
Connecting Process Pressure to the Transmitter
Impulse line arrangements and compatible valve manifold integration for safe transmitter maintenance.
Impulse Lines
In many differential-pressure installations, process pressure is transferred from the measurement points on the main pipe or vessel to the transmitter's HP and LP ports through suitable impulse piping or tubing.
Impulse-line arrangement depends on the measured medium (liquid, gas, steam), process temperature, transmitter mounting location, and slope requirements to avoid air trapping or sediment accumulation.
Manifold Integration
A compatible valve manifold (e.g. 3-valve or 5-valve manifold) can support process isolation, zero equalization and safe maintenance operations on differential-pressure installations without shutting down the main process line.
Installation Note: Manifolds and impulse hardware are selected according to process specifications. Always follow certified site engineering and manufacturer safety procedures for pressurized lines.
System Integration
From Differential Pressure to Process Monitoring
Seamless signal transmission from dual process points into local indication and plant automation architecture.
Differential Pressure Transmitter
Dual HP / LP Process Inputs & Integrated Display
↓
Calibrated ΔP Variable
Electronic Signal Processing (ΔP = HP − LP)
↓
Process Signal Output
Supported Industrial Output / Current Loop
↓
Local Indicator / Controller
FlowDo Digital Process Indicator / FDI Series
PLC / Control System
Automation Logic, Interlocks & Flow Calculations
↓
SCADA & Plant Telemetry
Centralized operational dashboards, logging & alarms
Product Selection
Choose the Right Pressure Instrument Architecture
Comparison of primary FlowDo industrial pressure measurement solutions.
Differential Pressure Transmitter
- Measurement
- Measures pressure difference between two inputs (ΔP = HP − LP).
- Process Inputs
- Dual process ports (High Pressure & Low Pressure).
- Local Display
- Integrated front digital display for direct on-site readout.
- Typical Applications
- Filter pressure drop, differential flow systems, closed tank level, heat exchanger monitoring.
Smart Type Pressure Transmitter
- Measurement
- Single-point gauge or absolute pressure relative to reference.
- Process Inputs
- Single primary process connection.
- Local Display
- Integrated front digital display for local process visibility.
- Typical Applications
- Line, vessel, pump discharge, and general industrial process monitoring.
Pencil Type Pressure Transmitter
- Measurement
- Compact single-point direct pressure measurement.
- Process Inputs
- Single process threaded port.
- Local Display
- Direct transmitter output without integrated front display.
- Typical Applications
- OEM machinery, tight piping manifolds, and space-constrained installations.
Final selection should be based on pressure range, static pressure, process medium, local-display requirement, connection, output, installation environment and automation requirements.
Applications
Industrial Process Applications
Reliable differential pressure measurement across industrial processing and plant operations.
Filter Monitoring
Differential pressure measurement across industrial liquid, air, and gas filter assemblies.
Flow Measurement
Differential-pressure sensing across orifice plates, Venturi tubes, and flow nozzles.
Process Equipment
Pressure-drop monitoring across industrial reactors, strainers, and process equipment.
Heat Exchangers
Monitoring differential pressure across tube and plate heat exchangers to detect fouling.
Water Treatment
DP monitoring across sand filters, membrane systems, and clarifier processes.
Closed Tank Level
Liquid level measurement in pressurized vessels using vapor-space head compensation.
Pumping Systems
Differential pressure verification across pumps and balance lines where specified.
HVAC / Duct Systems
Differential pressure measurement across ventilation filters and air handling units where suitable.
Industrial Processing
General process pressure-difference monitoring and automated control interlocks.
Application Engineering
What Should Be Considered Before Selecting a Differential Pressure Transmitter?
Key technical parameters to define for configuring an optimal differential pressure transmitter.
Differential Pressure (ΔP)
Minimum, normal, and maximum expected ΔP span, plus required measuring sensitivity and resolution.
Static / Line Pressure
HP line pressure, LP line pressure, and the maximum static process pressure the transmitter will experience.
Process Medium
Liquid, gas, vapor, or steam medium, verifying chemical compatibility and viscosity for wetted materials.
Process Conditions
Process and ambient temperatures, potential pressure pulsation, vibration, condensation, and outdoor exposure.
Mechanical & Piping
HP/LP port thread size, impulse piping arrangement, manifold requirement, mounting bracket, and materials.
Electrical & Output
Required output signal, power supply, local display, cable entry standard, and PLC / SCADA interface.
Installation Engineering
Installation Considerations
Best practices for mechanical mounting, process connection, and commissioning.
01 — HP / LP Connection
Port Alignment
Connect process points according to the intended high- and low-pressure measurement arrangement.
02 — Measuring Span
Range Selection
Select a DP range appropriate for the expected pressure difference to ensure measurement accuracy.
03 — Pressure Rating
Static Pressure
Ensure the transmitter body and sensor are rated for the actual maximum process line/static pressure.
04 — Material Compatibility
Process Medium
Confirm wetted-material compatibility with corrosive, abrasive, or aggressive process fluids.
05 — Piping Arrangement
Impulse Lines
Where used, impulse lines should be arranged appropriately for the process medium, sloping properly to prevent trapping.
06 — Temperature Limits
Thermal Verification
Verify process and ambient operating temperature limits to protect transmitter electronics.
07 — Physical Mounting
Rigid Mounting
Install the transmitter securely using suitable pipe or wall mounting hardware according to guidance.
08 — Valve Manifolds
Manifold Integration
If used, ensure manifold compatibility with the transmitter and process for safe isolation.
09 — Electrical Wiring
Wiring Integrity
Follow wiring requirements for the selected output and power supply, ensuring proper conduit sealing.
10 — Commissioning
Configuration
Configuration and commissioning should follow the actual FlowDo model documentation and parameters.
Process Safety & Installation Notice: Differential-pressure transmitter installation can involve pressurized process connections. Installation, isolation, commissioning and maintenance should follow the applicable FlowDo product documentation and site engineering/safety procedures.
Product Configuration
Configure the Differential Pressure Transmitter for Your Application
Key configuration parameters required to identify the correct transmitter configuration.
Differential Pressure Range
Required ΔP span (minimum, operating, maximum)
Static / Line Pressure
Maximum common process line pressure
Process Medium
Liquid / gas / vapor / compatible process medium
HP Connection
Connection size and type according to process arrangement
LP Connection
Connection size and type according to process arrangement
Wetted Material
Diaphragm and flange material according to medium compatibility
Output Signal
According to automation requirement
Power Supply
According to selected model
Local Display
Integrated digital indication where specified
Manifold Requirement
Direct mount or remote impulse arrangement
Related Instrumentation
Related Pressure & Process Instruments
Explore complementary FlowDo instruments for pressure measurement, level sensing and digital process indication.
Smart Type Pressure Transmitter
Smart industrial pressure transmitter with integrated digital display for single-point process monitoring.
View details & specs →
Pencil Type Pressure Transmitter
Compact stainless-steel pressure transmitter designed for reliable pressure measurement in tight industrial piping.
View details & specs →
Digital Process Indicator
FDI Series Programmable panel-mounted digital indicator for clear local monitoring of transmitter signals.
View details & specs →
Hydrostatic Level Transmitter
Model FLD-HLT Submersible level transmitter measuring hydrostatic liquid column pressure in tanks and sumps.
View details & specs →Frequently Asked Questions
Differential Pressure Transmitter FAQs
Common technical questions regarding industrial differential pressure measurement.
What is a Differential Pressure Transmitter?
A differential pressure transmitter measures the difference between two process pressure points, generally identified as the high-pressure (HP) and low-pressure (LP) inputs.
How is differential pressure calculated?
Differential pressure (ΔP) is calculated as the difference between the pressure applied to the high-pressure side and the pressure applied to the low-pressure side (ΔP = HP − LP).
What is the difference between a pressure transmitter and a differential pressure transmitter?
A standard pressure transmitter measures pressure at a single process point relative to its reference (gauge or absolute), while a differential pressure transmitter compares two process inputs simultaneously.
What are HP and LP ports?
HP refers to the high-pressure input port and LP refers to the low-pressure input port of a differential-pressure measurement system.
Can a DP transmitter be used for filter monitoring?
Yes, differential pressure is commonly used to monitor pressure drop across suitable filters when the installation and transmitter range are correctly selected.
Can it be used for flow measurement?
A differential pressure transmitter can be part of a flow-measurement system using a suitable primary flow element (such as an orifice plate or Venturi) and appropriate system configuration. The transmitter itself measures differential pressure.
Can it measure tank level?
Differential-pressure measurement can be used as part of level-measurement systems in certain pressurized tank/vessel applications, but proper engineering of process connections, density and pressure conditions is required.
What is static pressure?
Static or line pressure refers to the process pressure acting on the transmitter inputs in addition to the differential pressure being measured.
Why is the static-pressure rating important?
The transmitter body and sensor must withstand the actual process line pressure while accurately measuring the much smaller difference between the two ports.
Can it provide 4–20 mA output?
4–20 mA is available for FlowDo configurations confirmed to support standard analog current loop output.
Does it support digital communication?
Digital communication options (such as HART or Modbus) are available where verified for the selected FlowDo model and order configuration.
Can it connect to PLC or SCADA?
Yes, where the selected transmitter output or communication interface is compatible with the plant automation architecture.
Does it require a manifold?
A valve manifold may be used in some differential-pressure installations for isolation and equalization. Requirement and compatibility depend on the selected transmitter and process arrangement.
How do I select the correct DP transmitter?
Provide the expected differential-pressure range, static/line pressure, process medium, process temperature, HP/LP connection arrangement, required output and installation conditions to FlowDo.
Need Help Selecting a DP Transmitter?
Configure the Right Differential Pressure Transmitter for Your Process
Share your differential-pressure range, line/static pressure, process medium, temperature, HP/LP connection arrangement and required output with FlowDo to identify a suitable transmitter configuration.
For faster selection, provide: Differential Pressure Range • Static / Line Pressure • Process Medium • Process Temperature • HP Connection • LP Connection • Required Output • Manifold Requirement