43AP-PA42C/XX-XX FOXBORO

Product Overview

The FOXBORO 43AP-PA42C/XX-XX is a Model 43AP Pneumatic Indicating Controller, manufactured by Foxboro (now part of Schneider Electric). It is a robust and highly dependable analog instrument designed for continuous measurement, indication, and control in industrial processes using air pressure signals. It measures a process variable (either directly or via a pneumatic signal from a transmitter), compares it to a set point, and produces a proportional pneumatic output signal (air pressure) to control a final control element, typically a control valve.

Let’s break down the known parts of the model number:

43AP: Denotes the basic model, a Pneumatic Indicating Controller.
-PA: (Assuming similar to -FA) This likely indicates a mounting style or series variant. In most common 43AP models, “F” stands for Field Mounting (pipe or yoke). If “PA” signifies a different mounting (e.g., panel mount), it would affect physical installation, but the 43AP is primarily a field-mounted instrument.
-A4: Specifies the control action as Proportional plus Integral (Reset). This combination (P+I or PI control) provides a proportional response to the error and also eliminates steady-state offset (the. The integral (reset) range is typically 0.01 to 50 minutes per repeat.
-2: Refers to the Output Signal and Gauge: a standard 3 to 15 psi (pounds per square inch) pneumatic output air signal, with a local 0 to 30 psi output gauge for visual feedback.
-C: Designates the Automatic Manual Internal Transfer Switching as “Bumpless”. This feature includes a 2-position switch, a balance gauge, and a regulator, allowing for smooth, bumpless transfer between automatic and manual control modes without disturbing the process.
/XX-XX: This is the unspecified part of the model number. It represents the Measuring Element Type and its specific range. This is a critical part of a 43AP model number, as it defines what the controller is designed to measure directly. Without this, the specific application is unknown. Common options for this section include:
- /PC-00: Pressure Receiver (for 3-15 psi pneumatic input from a transmitter)
- /PB-AA, /PB-BA, etc.: Pressure (Bellows) for direct low to medium pressure measurement (e.g., 0-15 psi, 0-60 psi)
- /PA-CC, /PA-DD, etc.: Pressure (Helical) for direct high-pressure measurement (e.g., 0-2000 psi, 0-10,000 psi)
- /TR-00: Temperature (with a filled thermal system for direct measurement)
- Other specific element types for flow, level, etc.

To get a complete understanding of the controller’s function, the exact “XX-XX” code for the measuring element is necessary.

Technical Specifications (General)

Since the measuring element is unspecified, some technical specifications related to the input will be general.

Parameter Name	Parameter Value
Product Model	43AP-PA42C/XX-XX
Manufacturer	Foxboro (now part of Schneider Electric)
Product Type	Pneumatic Indicating Controller
Measurement Input	Determined by XX-XX (e.g., direct process pressure, temperature, or a 3-15 psi pneumatic signal)
Measuring Element	Determined by XX-XX (e.g., Bellows, Helical, Thermal System, Pressure Receiver)
Control Type	Proportional plus Integral (Reset) (P+I or PI)
Output Signal	3 to 15 psi (pneumatic air signal)
Output Gauge	0 to 30 psi
Input to Pointer Accuracy	±0.5% of span (typical, varies slightly by element type)
Repeatability	0.2% of span
Deadband	0.1% of span
Air Consumption (Normal Op.)	0.5 m³/h (0.3 cfm) at standard conditions
Supply Air Pressure	20 psi (140 kPa) nominal; operating range 17 to 23 psi (115 to 155 kPa)
Ambient Temperature Limits	-40 to 80°C (-40 to 180°F) operative limits; -30 to 80°C (-20 to 180°F) normal operating conditions
Mounting	Field (Pipe or Yoke mounted, assuming ‘PA’ variant is functionally similar to ‘FA’ for typical 43AP)
Automatic/Manual Transfer	Bumpless with 2-position switch, balance gauge, regulator
Case Construction	Glass fiber reinforced polyester molding with a shatterproof polycarbonate window, weatherproof (meets IEC IP53, NEMA Type 3)
Approximate Mass	4.8 kg (10.6 lb) (varies slightly with element type)

Main Features and Advantages (General)

The FOXBORO 43AP-PA42C/XX-XX shares the fundamental strengths of the 43AP series:

Versatile Measuring Element (XX-XX): The “XX-XX” placeholder signifies the ability of the 43AP series to incorporate various measuring elements. This allows the controller to be configured for a wide array of process variables:

Direct Measurement: If configured with a direct element (like /PB or /PA for pressure, or /TR for temperature), it simplifies the control loop by eliminating the need for a separate transmitter, often enhancing response speed and reducing total cost.
Receiver Input: If configured as a /PC (Pressure Receiver), it accepts a 3-15 psi pneumatic signal, allowing it to control variables measured by remote pneumatic transmitters.

Inherent Safety and Robustness: As a purely pneumatic instrument, it is intrinsically safe and immune to electrical noise, electromagnetic interference (EMI), and radio frequency interference (RFI). This makes it highly suitable for hazardous (explosion-proof) environments without the need for additional safety barriers or specialized enclosures, a major advantage over electronic counterparts in certain applications.

Proven Reliability: The 43AP series has a long and established history of reliable operation in harsh industrial conditions. Its mechanical design contributes to its durability and resistance to environmental factors like temperature extremes and vibration.

Proportional plus Integral (Reset) Control: The “A4” control action provides the essential combination of proportional response (reacting to the error) and integral action (eliminating steady-state offset), ensuring precise and stable control of the process variable at the setpoint over time.

Bumpless Auto/Manual Transfer (“C” option): This is a critical operational feature that enables operators to switch smoothly between automatic and manual control modes without introducing sudden changes or disturbances to the process output. This enhances operational stability and minimizes process upsets.

Local Indication: The controller provides a direct, mechanical indication of the process variable, the set point, and the output control signal. This allows operators to quickly monitor and assess the process status directly in the field.

Field Mountable (Assuming -PA is similar to -FA): Designed for mounting directly on a pipe or yoke, typically close to the process or control valve. This simplifies pneumatic piping and reduces potential signal lag.

Application Field (General)

The FOXBORO 43AP-PA42C/XX-XX finds applications across process industries that utilize pneumatic instrumentation, with the specific application depending entirely on the “XX-XX” measuring element:

If /PC (Pressure Receiver): Used in chemical, oil & gas, power, pulp & paper, water & wastewater industries to control any process variable (flow, level, temperature, pressure) that is first converted into a 3-15 psi pneumatic signal by a remote transmitter.
If /PB or /PA (Direct Pressure): Used in chemical, oil & gas, and power industries for direct control of process pressure (low to high range depending on the specific element).
If /TR (Direct Temperature): Used in any industry requiring direct temperature control (e.g., heat exchangers, small reactors).

Essentially, the 43AP-PA42C/XX-XX would be found wherever robust, reliable, intrinsically safe, and locally indicating pneumatic control is desired for a process variable that matches its measuring element.

Related Products (General)

The FOXBORO 43AP-PA42C/XX-XX operates as part of a pneumatic control loop. Its related products include other Foxboro pneumatic devices and essential auxiliary equipment, depending on the specific “XX-XX” configuration:

If /PC (Pressure Receiver):
- Foxboro Pneumatic Transmitters: (e.g., 13A Series DP Transmitters, 12A Series Force Balance Transmitters) are essential as they provide the 3-15 psi input signal to the controller.
In all configurations:
- Pneumatic Control Valves: The final control elements that receive the 3-15 psi output signal. These typically include a valve body and a pneumatic actuator.
- Pneumatic Valve Positioners: (e.g., Foxboro 69P or 69F) are often used with control valves to ensure precise positioning and overcome friction.
- Instrument Air Supply System: Including air filters, dryers, and regulators to provide clean, dry, regulated 20 psi air to the controller.
- Pneumatic Tubing and Fittings: For all pneumatic connections.
- Pneumatic Relays and Boosters: Used for amplifying or speeding up signals to large valve actuators.
Interface Components (for hybrid systems):
- Pneumatic-to-Electric (P/I) Converters: If the pneumatic output (3-15 psi) needs to be sent to a modern electronic DCS or PLC.
- Electric-to-Pneumatic (I/P) Converters: If an electronic controller needs to send a signal to a pneumatic control valve that might also interact with the 43AP.