Intelligent Differential Pressure Transmitter IDP50


The I/A Series® differential pressure IDP50 is an intelligent, premium performance, two-wire d/p Cell® transmitter that provides precise, reliable, measurement of differential pressure to provide a very wide measurement range. Optionally, a gauge pressure configuration is also offered. The transmitter transmits a 4 to 20 mA or digital output signal, as applicable, using HART or FOUNDATION Fieldbus communication protocol for remote configuration, calibration, and monitoring.


  • Silicon strain gauge sensors successfully fieldproven in many thousands of applications.
  • Wide measurement spans from 0.63 kPa to 14 MPa (2.5 inH2O to 2000 psi) using sensors having 80:1 turndown capability.
  • Digital precision, stability, and resolution ensure premium measurement performance with linear output accuracy of ±0.025% of calibrated span for spans ≥10% of URL.
  • Transmitter available with traditional or low profile transmitter structures (see photos above).
  • Local configuration available with the optional LCD Indicator with on-board pushbuttons.
  • Simple sensor packaging with very few parts achieves exceptionally high reliability.
  • Can be provided as a sealed measurementsystem with numerous configurations of direct connnected or capillary connected seals available.
  • Durable aluminum or 316 ss housing available; both meet NEMA 4X and IP66 ratings.
  • Industry Standard 316L ss offered for sensor wetted parts materials. Complies with applicable EMC and PED European Union Directives. See inside pages.
  • FOUNDATION Fieldbus versions are FISCO and FNICO compliant.
  • Dual Seal Certified by CSA to meet ANSI/ISA 12.27.01-2003 requirements.
  • Multi-marking is available for HART electronic versions for FM, CSA, and ATEX intrinsically safe installations. The user determines and permanently marks on the data plate the certification to be applied.
  • Designed for hazardous area installations. Versions available to meet agency flameproof and zone requirements.
  • Option -G2 allows a gauge pressure configuration with the IDP50. Optional mounting bracket sets allow pipe, surface, or manifold mounting of transmitter.
  • Standard 5-year warranty; 17-year optional.


The I/A Series Electronic Pressure Transmitters are acomplete family of d/p Cell, gauge, absolute, multirange, multivariable, and premium performance transmitters, as well as transmitters with remote or direct mount seals, all using field-proven silicon strain gauge sensors and common topworks.


These transmitters provide linear output accuracy of±0.025% of calibrated span for spans ≥10% of URL. This makes the IDP50 the most versatile of the “premium” or “reference class” transmitters available.
The transmitters have ±0.02% URL per year stability over a five year period and use characterization and microprocessor-based corrections to achieve excellent ambient temperature compensation.
These premium performance specifications, along with reduced static pressure effect on both zero and span, result in an extremely low Total Probable Error (TPE) for the IDP50 transmitter.


Four sensors are provided to cover measurement spans from 0.63 kPa to 14 MPa (2.5 inH2O to 2000 psi). The high turndown capability of the transmitter means that nearly all d/p applications can be satisfied with only four sensors, greatly simplifying your spare transmitter and spare parts requirements.


Removable, gasketed process connectors allow a wide range of selections, including 1/4 NPT, 1/2 NPT, Rc 1/4, Rc 1/2, and weld neck connections.


Industry standard 316L ss sensor material is provided as standard for corrosion protection. Refer to Model Code for other available materials.


HART and FOUNDATION Fieldbus Communication protocols are described below.

Digital HART and 4 to 20 mA dc
(Version -T Electronics)

4 to 20 mA with HART communications. Allows direct analog connection to common receivers while still providing full Intelligent Transmitter Digital Communications using a PC-based configurator or HART Communicator, or optional LCD indicator with on-board pushbuttons for local configuration and calibration.
Users having HART Communicators for other devices can have them upgraded with Invensys software to accommodate these transmitters. Also, Invensys makes use of the HART Foundation library of registered DDs (Device Descriptors), and reload the Communicator if the user desires to keep another supplier's DD along with the Foxboro DD.

Digital FOUNDATION Fieldbus
(Version -F Electronics)

This all digital, serial, two-way communication system interconnects field devices, such as transmitters, actuators, and controllers. It is a Local Area Network (LAN) with built-in capability to distribute control application across the network. Fieldbus technology consists of a Physical Layer, a Communication Stack, and User Application Blocks. The Communication Stack includes an LAS (Link Access Scheduler), and the User Application Blocks include AI (Analog Input) and PID (proportional, integral, derivative) function blocks. Interoperability of fieldbus devices is achieved using device addresses (IDs) and device descriptors (DDs).


FOUNDATION Fieldbus Version (Electronic Version -F) certified by ATEX and IECEx for FISCO field device intrinsically safe, and FNICO field device protection n installations. Also certified for intrinsically safe and nonsparking user entity parameters.


Complies with Electromagnetic Compatibility Requirements of European EMC Directive 2004/108/EC by conforming to the following EN and IEC Standards: EN 61326-1 and IEC 61000-4-2 through 61000-4-6.
Complies with NAMUR NE 21 Interference Immunity Requirement. Analog output complies with NAMUR NE 43 overrange and underrange annunciations.
CE marked; complies with applicable EMC, ATEX, and PED European Union directives.


See Electrical Safety Specifications section.


Rotatable Topworks allows transmitter installation in tight places, allows indicator to be positioned in preferred direction, and eases field retrofit.
Two Conduit Entrances offer a choice of entry positions for ease of installation and self-draining of condensation regardless of mounting position and topworks rotation.
Wiring Guides and Terminations provide ease of wire entry and support, plenty of space to work and store excess wire, and large, rugged screw terminals for easy wire termination.


A two-line digital indicator with on-board pushbuttons is available to display the measurement with a choice of units. The pushbuttons allow zero and span adjustments, as well as local configuration, without the need for a PC-based configurator.


In addition to the standard style mounting bracket sets optionally offered with these transmitters, a unique universal style mounting bracket has been developed to allow wide flexibility in transmitter mounting configurations consistent with installation requirements. All mounting bracket sets allow mounting to a surface, pipe, or manifold. Refer to Dimensions - Nominal section.


Biplanar Construction (Figure 1) maintains the traditional horizontal process connections and vertical mounting by providing a cell body contained between two process covers, while still achieving light weight, small size, and high standard static pressure rating of 25 MPa (3625 psi). This provides easy retrofit of any conventional differential pressure transmitter, and also is easily mounted in the horizontal position with vertical process connections, when required.
Process Covers (Figure 1) are fully supported by the cell body over their entire height. This prevents bending and results in a highly reliable seal. Also, this provides dimensional stability to the process covers, ensuring that they will always mate properly with 3 valve bypass manifolds.
Process Cover Bolts (Figure 1) are enclosed to minimize corrosion and to minimize early elongation with rapid temperature increases. The design makes it less likely for the transmitter to release process liquid during a fire.
Process Cover Gaskets are ptfe as standard; ptfe provides nearly universal corrosion resistance, and eliminates the need to select and stock various elastomers to assure process compatibility. Light Weight provides ease of handling, installation,and direct mounting without costly pipe stands.


Traditional and low profile structures (LP1 and LP2) are offered to accommodate and to provide flexibility in transmitter installations. See paragraphs below.

Traditional Structure

The traditional structure (Figure 2) utilizes the right angle design common to most differential pressure transmitters in use throughout the world. Process connections are oriented 90 degrees from the transmitter centerline.
This traditional structure makes it easy to retrofit any transmitters of similar design.
Sensor cavity venting and draining is provided for both vertical and horizontal transmitter installation, using innovative tangential connections to the sensor cavity (Figure 3 and Figure 4). Optional side vents are offered for sensor cavity venting in the upright position (Figure 5).
A variety of process-wetted materials are available for the process covers on this highly versatile and widely used transmitter. Refer to the sections that follow for descriptions of low profile structure LP1 and low profile structure LP2.

Low Profile Structures

The low profile structures utilize an in-line design, placing the process connections in line with the transmitter centerline (Figure 6 and Figure 7). This allows mounting of the transmitter in the upright position with the process connections facing downward, for connection to vertical process piping or for mounting directly to a three- or five-valve manifold.
The low profile structures provide a mounting style similar to that used by competitive Coplanar™ transmitters. This makes it easy to select Foxboro transmitters for both retrofit and new applications where this type of installation is desired.
Transmitters with the low profile structure can be attached directly to existing, installed Coplanar manifolds, such as the Rosemount Model 305RC or Anderson Greenwood Models MB3, MB5G, and MB5P by use of an optional adapter plate (see Figure 8). Also, when assembled to the same process piping or manifold as a Coplanar transmitter, one of the electrical conduit connections is located within one inch (plus or minus) of the similar conduit connection on the competitive transmitter, assuring ease of retrofit or conformance with installation design drawings.
All parts making up the low profile versions are identical to the parts in the traditional version except for the process covers and the external shape of the sensor cell body.
For user convenience, two types of low profile structures are offered, type LP1 and LP2. The process covers are the only transmitter parts that differ between structure types LP1 and LP2.
Refer to the sections that follow for further descriptions of low profile structures LP1 and LP2.

Low Profile Structure LP1 – Direct Mount

Low Profile Structure LP1 is a compact, inexpensive, lightweight design for direct mounting to a separately mounted manifold or process piping. These transmitters are not typically bracket-mounted. They are supplied as standard with a single vent/drain screw in the side of each process cover. In conjunction with the standard tangential venting and draining design, they are suitable for mounting either vertically (Figure 9) or horizontally, and are suitable for nearly all applications, including liquids, gases, and steam. For horizontal installation, they can simply be “turned over” (rotated 180 degrees – Figure 10 and Figure 11) to orient the high and low pressure sides in the preferred locations. There is no need to unbolt process covers. The topworks housing can also be rotated, as shown, to orient the conduit connections in the desired position.
In the vertical, upright position, they are also selfdraining and are ideal for gas flow rate service, when directly mounted to a manifold located above the horizontal pipeline.
The vent screw can be omitted for this or other applications, if desired.

Low Profile Structure LP2 - Bracket or Direct Mount

Structure LP2 is a universal design for either bracket or direct mounting. Drilled and tapped mounting holes facilitate mounting to either new or existing Foxboro brackets (Options -M1, -M2, and -M3), as well as standard brackets supplied with existing Coplanar transmitters. See Figure 12 and Figure 13.
These transmitters can also be directly mounted to manifolds or process piping and are available with the same optional adapter used with low profile structure LP1 to fit existing Coplanar manifolds (Figure 14). For extra convenience, they use a full-featured vent and drain design, with separate vent and drain screws positioned in each cover for complete venting or draining directly from the sensor cavity. They are normally recommended for upright, vertical installation.


Pressure seals are used with transmitters having atraditional structure (see Transmitter Structures section above) when it is necessary to keep the transmitter isolated from the process. A sealed system is used for a process fluid that may be corrosive, viscous, subject to temperature extremes, toxic, sanitary, or tend to collect and solidify.
Table 1 lists the various pressure seals that can be used with an IDP50 Transmitter. To order a transmitter with seals, both a Transmitter Model Number and Seal Model Number are required. For a complete listing of pressure seal models and specifications, see PSS 2A-1Z11 A. Also see Figure 15 for typical pressure seal configurations.

Output Signal and Configuration
HART Protocol (Version -T)

4 to 20 mA with HART Communications. When configured for multidrop applications, the mA signal is fixed at 4 mA to provide power to the Transmitter. Configurable using the HART Communicator, a PC-based configurator, or the optional LCD indicator.
Foundation Fieldbus Protocol (Version -F)
This digital, serial, two-way communication system runs at 31.25 kbits/s. The digital output signal is superimposed on the dc power signal on the bus, and controlled by a strict cycle schedule and protocol. Configurable using Host Computer (I/A Series System Workstation or a PC) having a fieldbus interface PWA, or optional LCD indicator.

Electronics and Sensor Temperatures

Readable from I/A Series System, HART Communicator, Fieldbus Host System, or PC-based configurator. Measurement is transmitter temperature at the sensor and the electronic module, not necessarily process temperature.

Adjustable Damping

The transmitter response time is normally 0.8 s, or the electronically adjustable setting of 0.00 (none), 0.25, 0.50, 1, 2, 4, 8, 16, or 32 seconds, whichever is greater, for a 90% recovery from an 80% input step as defined in ANSI/ISA S51.1 (for 63.2% recovery, 0.60 s). With FOUNDATION Fieldbus, additional damping is available because damping can be set on both the Transducer and AI blocks.

Suppressed Zero and Elevated Zero

Suppressed or elevated zero ranges acceptable as long as Span and Range Limits are not exceeded.

Zero and Span Adjustments

Zero and span adjustments can be initiated from any of the following: I/A Series Workstation (with applicable FBMs), HART Communicator, a PC-based configurator, or the optional LCD indicator with onboard pushbuttons.

Zeroing for Nonzero-Based Ranges

Dual Function Zeroing is provided to allow zeroing with the transmitter open to atmosphere, even when there is a nonzero-based range. This greatly simplifies position effect zeroing on many pressure and level applications. It applies to optional LCD indicator pushbuttons and optional External Zero Adjustment.

Supply Voltage
Digital Output

Version -T Electronics (HART): Bidirectional digital signal superimposed on the 4 to 20 mA current signal. Version -F El ectronics (FOUNDATION Fieldbus): Power supplied through a specific Fieldbus power supply connected to the bus.

4 to 20 mA (HART/-T)

Minimum voltage shown in Figure 16 is 11.5 V dc. This can be reduced to 11 V dc by using a plug-in jumper on the terminal block. See Figure 22.

Square Root Low Flow Cutoff

User configurable to provide: Cutoff to Zero at Flows < 10% of Maximum Flow(1% of Maximum Differential Pressure).
Or Active Point-to-Point Line between Zero and 20% of Maximum Flow (4% of Maximum Differential Pressure).
Flow Cutoff in Engineering Units (Fieldbus Only)

Field Wiring Reversal

No transmitter damage. Note that FOUNDATION Fieldbus is polarity independent.

Write Protect Jumper

Can be positioned to lock out all configurators from making transmitter database changes. This makes transmitter suitable for Safety Shutdown System Applications that require this feature.

Minimum Allowable Absolute Pressure

The transmitter may be used to full vacuum with process temperatures up to 121°C (250°F).

Configuration and Calibration Data, and Electronics Upgradeability

All factory characterization data, and user configuration and calibration data, are stored in the sensor. This means that the electronics module canbe replaced or changed from one type to another.
A module may be replaced without the need for reconfiguration or recalibration. Although module replacement can affect accuracy up to 0.20% of span, this error can be removed by an mA trip without application of pressure.
Changing module types may require reconfiguration and recalibration, as well as a different terminal block,if applicable, but all factory characterization data is retained.

Configuration Capability (See Note below)

Calibrated Range
– Input range within Span and Range Limits.
– Pressure EGU (see Table 2).
Output Measurement #1 — Digital Primary
Variable; and 4 to 20 mA (HART only)
– Mode: Linear or Square Root
– Units for Linear Mode: Same as calibrated range
– Units for Square Root Mode: % of flow
Output Measurement #2 — Digital Secondary Variable
– Mode: Linear or Square Root
(Independent of Measurement #1)
– Units for Linear Mode: A common pressure EGU
– Units for Square Root Mode: % of flow
– Measurements #1 and #2 may be swapped.
Numerous parameters can be configured and/or displayed, such as electronic damping, failsafe direction, transmitter location, calibration, tag data, etc. See configuration documents for details.

HART (Version -T) Communications

4 to 20 mA Analog Mode Analog output signal is updated 30 times per second. A minimum loop load of 250 ohms is required. See Table 3 for communication parameters.
Multidrop Mode (Fixed Current) This mode supports communications with up to 15 transmitters on a single pair of signal/power wires. The output signal is updated 4 times/second. A minimum loop load of 250 ohms is required. See Table 3 for communication parameters.

Optional LCD Indicator with On-Board Pushbuttons (Figure 17)

Indicator provides:
Two Lines; five numeric characters on top line (four when a minus sign is needed) and seven alphanumeric characters on bottom line.
Measurement Readout; value on top line and units label on bottom line.
Configuration and Calibration Prompts. Two pushbuttons provide for:
Configuration Functions
Calibration Functions

FOUNDATION Fieldbus (Version -F)Communications

This serial, two-way communication system runs at 31.25 kbits/s. The digital output signal is superimposed on the dc power signal on the bus, and controlled by a strict cycle schedule and protocol. Supply voltage, 9 to 32 V dc, is by a specific Fieldbus power source. Current consumption is 19.5 mA. The maximum number of devices on a non-intrinsically safe bus is 32. For intrinsically safe bus systems the maximum number is 5.

Optional External Zero Adjustment (Figure 17)

An external pushbutton mechanism is isolated from the electronics compartment and magnetically activates an internal reed switch through the housing. This eliminates a potential leak path for moisture or contaminants to get into the electronics compartment. This external zero adjustment can be disabled by a configuration selection.

Optional Custom Configuration (Option -C2)

For the transmitter to be custom configured by the factory, the user must fill out a data form. If this option is not selected, a standard default configuration will be provided.


Long term drift is ±0.15% of URL for 10 years (reference conditions).

Calibration Frequency

The calibration frequency is five years. The five years is derived using the values of allowable error (% span), TPE (% span), performance margin (% span), and stability (% span/month).
Calibration Frequency = Performance Margin /Stability = x Months

Power-up Time

Less than 5 seconds for output to reach first valid measurement.

Supply Voltage Effect

The output changes less than 0.005% of span for each 1 V change within the specified supply voltage requirements.

RFI Effect

The output error is less than 0.1% of span for radio frequencies in the range of 27 to 1000 MHz and field intensity of 30 V/m when the transmitter is properly installed with shielded cable in conduit and earthing (grounding), and housing covers are in place. (Per IEC Std. 61000-4-3.)

Vibration Effect

Total effect is ±0.2% of URL per “g” for vibrations in the frequency range of 5 to 500 Hz; with double amplitudes of 6.3 mm (0.25 in) in the range of 5 to 15 Hz, or accelerations of 3 “g” in the range of 15 to 500 Hz, whichever is smaller, for transmitter with aluminum housing; and with double amplitudes of 6.3 mm (0.25 in) in the range of 5 to 9 Hz, or accelerations of 1 “g” in the range of 9 to 500 Hz, whichever is smaller, for transmitter with 316 ss housing.

Position Effect

Transmitter may be mounted in any position. Any zero effect caused by mounting position can be eliminated by rezeroing. There is no span effect.

Static Pressure Effect

The zero and span shift for a 7 MPa, 1000 psi, change in static pressure is:
Span Shift
±0.1% of Reading for Span Limit Codes B and C.

Ambient Temperature Effect

Total effect for a 28°C (50°F) change from Reference Operating Conditions is: ±(0.015% URL + 0.030% Span)
Temperature effects due to pressure seal(s) are additive.

Switching and Indirect Lightning Transients

The transmitter can withstand a transient surge up to 2000 V common mode or 1000 V normal mode without permanent damage. The output shift is less than 1.0%. (Per ANSI/IEEE C62.41-1980 and IEC Std. 61000-4-5.)


Mounting Position

The transmitter may be mounted in any orientation.

Environmental Protection

The enclosure has the dusttight and weatherproof rating of IP66 as defined by IEC 60529, and provides the environmental and corrosion resistant protection rating of NEMA 4X.

Process Cover and Process Connector Gaskets

Glass filled ptfe (Chemloy)

Process Cover Bolts and Nuts

ASTM™ A193, Grade B7 high strength alloy steel for bolts, and ASTM A194 Grade 2H high strength alloy steel for nuts are standard. Options include NACE Class B7M bolting, 17-4 ss bolting, and 316 ss bolting.

Sensor Material (Process Wetted)

Refer to Model Code.

Process Cover and Connector Material (Process Wetted)

Refer to Model Code.

Sensor Fill Fluid

Silicone Oil.

Electronics Module

Printed wiring assemblies are conformally coated for moisture and dust protection.

Electronics Housing and Housing Covers

Housing has two compartments to separate the electronics from the field connections. The housing and covers are made from low copper, die-cast aluminum alloy with an epoxy finish, or from 316 ss. Buna-N O-ring seals are used to seal the threaded housing covers, housing neck, and terminal block.

Electrical Connections

Field wires enter through 1/2 NPT, PG 13.5, or M20 threaded entrances on either side of the electronics housing. Wires terminate under screw terminals and washers on terminal block in the field terminal compartment (Figure 22). Unused entrance is plugged to insure moisture and RFI/EMI protection.

Approximate Mass

3.5 kg (7.8 lb) – Aluminum housing; and without Process Connectors.
4.2 kg (9.2 lb) – Aluminum Housing; and with Process Connectors.
Add 1.1 kg (2.4 lb) – with 316 ss Housing.
Add 0.2 kg (0.4 lb) – with LCD Indicator Option.
Add pressure seal(s) mass.


See Dimensions-Nominal section and DP 020-446.



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