The FOXBORO 43AP-FA42C/PC-00GIDIAS-AG is a highly specific and feature-rich configuration of the classic Foxboro 43AP Pneumatic Indicating Controller. This instrument is designed for process control using pneumatic signals, specifically taking a pneumatic pressure signal as its input, and includes several advanced options like an integral air supply and a special gas compatibility feature.
Product Overview
The FOXBORO 43AP-FA42C/PC-00GIDIAS-AG is a Model 43AP Pneumatic Indicating Controller, manufactured by Foxboro (now part of Schneider Electric). This is a robust and highly reliable analog instrument designed to continuously measure a process variable (via a pneumatic signal), compare it to a set point, and produce a proportional pneumatic output signal (air pressure) to control a final control element, typically a control valve.
Let’s break down the complex model number:
- 43AP: Denotes the basic model, a Pneumatic Indicating Controller.
- -F: Indicates Field Mounting, meaning it’s designed to be mounted on a pipe or yoke, typically near the process.
- -A4: Specifies the control action as Proportional plus Integral (Reset). This is a common and effective control mode (P+I or PI) that provides a response proportional to the control error and also eliminates any steady-state offset (the difference between the setpoint and the actual process variable). 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. The controller also includes a local 0 to 30 psi output gauge for visual indication of the output pressure.
- -C: Designates the Automatic Manual Internal Transfer Switching as “Bumpless”. This feature incorporates a 2-position switch, a balance gauge, and a regulator, enabling smooth and “bumpless” transfers between automatic and manual control modes without disturbing the process.
- /PC: This is a crucial element. It indicates that the controller is equipped with a Pressure Receiver (Bellows) measuring element. This means the controller does not directly measure a process variable like temperature or pressure. Instead, its input is a standard pneumatic pressure signal (e.g., 3-15 psi) from a separate, remote pneumatic transmitter. This transmitter measures the actual process variable (like flow, level, temperature, or differential pressure) and converts it into a pneumatic signal, which then becomes the input to the 43AP-FA42C/PC controller.
- -00: This suffix usually denotes no additional standard optional features beyond those specified in the main model code and the /PC element.
- GID: This is a significant optional feature. “GID” likely refers to Gas Identification or a special Gas Service option, possibly related to internal venting or materials for use with gases other than standard instrument air, or for compliance in specific hazardous gas environments (though it’s important to note that a general “GID” doesn’t necessarily imply specific hazardous area certifications like FM Approval, which often require explicit certifications on the equipment itself). In the context of pneumatic instruments, this often means specific venting options (e.g., a vent connection on the case to pipe gas to a classified location) or material compatibility for the use of natural gas or other process gases as the operating medium instead of compressed air.
- IAS: This signifies an Integral Air Supply Set. This option means the controller includes an internal filter and adjustable pressure regulator to supply the necessary 20 psi instrument air to the controller’s internal pneumatic circuit. This simplifies installation by integrating the air supply conditioning directly into the unit.
- -AG: This suffix most commonly indicates the presence of an Air Gauge (or often just “Gauge”). In this context, with “IAS”, it likely means that the Integral Air Supply Set includes a local gauge to indicate the regulated supply pressure to the controller.
This configuration is particularly robust and versatile, designed for demanding environments where a reliable pneumatic signal is used as input and integrated air supply management is desired, possibly with considerations for specific gas media or venting.
Technical Specifications
Main Features and Advantages
The FOXBORO 43AP-FA42C/PC-00GIDIAS-AG combines the inherent strengths of the 43AP series with advanced features for enhanced versatility and reliability:
Pneumatic Receiver Input (/PC): This allows the controller to receive a standardized pneumatic signal (e.g., 3-15 psi) from a wide range of remote pneumatic transmitters. This flexibility enables the control of various process variables (flow, level, temperature, differential pressure, etc.) that are converted into a pneumatic signal, allowing the controller to be located at a convenient point away from the primary measurement.
Integral Air Supply Set (IAS) with Air Gauge (AG): This is a significant advantage. The integrated filter, adjustable regulator, and local gauge simplify installation and improve reliability by ensuring the controller receives a clean, regulated 20 psi air supply directly. This reduces external piping and the need for separate air supply components.
Gas Compatibility (GID): This feature (whose precise meaning would be detailed in Foxboro’s product specifications for the “GID” code) makes the controller suitable for applications where the operating medium is not standard instrument air, but potentially another gas (e.g., natural gas, specific process gas). This often involves special internal materials or, more commonly, a vent connection to safely pipe away any internal gas bleed to a classified or non-hazardous area. This expands its application in industries handling specific gases.
Inherent Safety and Robustness: As a purely pneumatic instrument, it is intrinsically safe and immune to electrical noise, EMI, and RFI. This makes it highly suitable for hazardous (explosion-proof) environments (e.g., oil & gas, chemical plants) without the need for complex electrical barriers or specialized enclosures. Its mechanical design provides exceptional durability in harsh industrial conditions.
Proven Reliability: The 43AP series has a long and established history of dependable operation in demanding industrial conditions, known for its robustness and longevity.
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 crucial operational feature allows operators to seamlessly switch between automatic and manual control modes without introducing sudden changes or disturbances to the pneumatic output, thereby enhancing operational stability and minimizing process upsets.
Local Indication: The controller provides a direct, mechanical indication of the process variable (derived from the input pneumatic signal), the set point, and the output control signal, allowing operators to quickly monitor process status directly in the field.
Field Mountable (“-F”): Designed for direct mounting on a pipe or yoke near the process or control valve, which simplifies pneumatic piping and potentially reduces signal lag.
Application Field
The FOXBORO 43AP-FA42C/PC-00GIDIAS-AG is particularly suited for applications within process industries that demand robust, reliable pneumatic control with enhanced air supply management and potential compatibility for specific operating gases. Its key application fields include:
Oil and Gas Production and Refining:
- Control loops in hazardous areas where the intrinsic safety of pneumatic devices is paramount.
- Applications where natural gas or other process gases are used as the control medium (enabled by GID option).
- Controlling flow, level, temperature, and pressure based on signals from remote pneumatic transmitters.
- Wellhead control, gas processing, and pipeline operations.
Chemical and Petrochemical Plants:
- Controlling parameters in distillation columns, reactors, and heat exchangers, receiving pneumatic signals from remote transmitters.
- In environments with corrosive atmospheres or where electronic interference is a concern.
- Processes requiring strict safety protocols regarding gas leaks or compatibility.
Power Generation (Traditional Plants):
- Boiler control systems (e.g., drum level control from a differential pressure transmitter, steam flow control), especially in older plants that maintain pneumatic infrastructure.
- Auxiliary systems where localized, reliable control is needed.
Pulp and Paper Mills:
- Controlling flow, level, and pressure in various stages of pulp processing and papermaking, often receiving signals from pneumatic flow or level transmitters.
Water and Wastewater Treatment:
- Regulating flow and levels in tanks, sumps, and treatment units, taking input from pneumatic level or flow transmitters.
In essence, this controller is ideal for complex pneumatic control loops that benefit from an integrated air supply system and require specific gas handling capabilities, all while maintaining the inherent safety and reliability of pneumatic instrumentation.
Related Products
The FOXBORO 43AP-FA42C/PC-00GIDIAS-AG operates within a comprehensive pneumatic control system. Its related products primarily include other Foxboro pneumatic devices that interact with it, along with essential infrastructure components.
Primary Interfacing Instruments:
- Foxboro Pneumatic Transmitters: These are the source of the 3-15 psi input signal for the 43AP-FA42C/PC-00GIDIAS-AG. Examples include:
- Foxboro 13A Series Differential Pressure Transmitters: For measuring flow, level, or differential pressure.
- Foxboro 12A Series Force Balance Transmitters: For pressure, temperature (with filled thermal systems), or other variables.
- Pneumatic Control Valves: These are the final control elements that receive the 3-15 psi output signal from the controller to manipulate the process. They typically consist of:
- A valve body (e.g., globe, butterfly, ball valve).
- A pneumatic actuator (diaphragm or piston type).
- Often, a pneumatic valve positioner (e.g., Foxboro 69P or 69F) which precisely positions the valve based on the 3-15 psi input, overcoming friction and process forces.
Pneumatic Infrastructure and Accessories:
- Instrument Air Supply System: While the “IAS” option means the controller has an integral regulator and filter, the overall plant must still provide a clean, dry, and adequately pressured air supply (e.g., 80-100 psi) to the controller’s supply port. This system includes:
- Main Air Dryers and Filters: To condition the plant air before it reaches individual instruments.
- Main Air Headers and Distribution Piping.
- Pneumatic Tubing and Fittings: For routing the instrument air supply, the input signal from the transmitter, and the output signal to the control valve. High-quality, leak-free connections are critical.
- Pneumatic Relays and Boosters: If the control valve is large or needs to actuate quickly, a pneumatic relay or volume booster might be used to amplify the 3-15 psi signal from the controller, providing higher air volume to the actuator for faster response.
Interface Components (for hybrid systems):
- Pneumatic-to-Electric (P/I) Converters: If the pneumatic output (3-15 psi) from the 43AP-FA42C/PC-00GIDIAS-AG needs to be integrated into a modern electronic Distributed Control System (DCS) or Programmable Logic Controller (PLC) that uses electrical signals (e.g., 4-20mA).
- Electric-to-Pneumatic (I/P) Converters: If an electronic controller or DCS needs to send a signal to a pneumatic control valve, but the 43AP is acting as a local backup or cascade element.
Installation and Maintenance
Pre-installation preparation: The installation of the FOXBORO 43AP-FA42C/PC-00GIDIAS-AG requires careful attention to safety, mechanical mounting, and pneumatic connections, especially considering its integral air supply and potential gas compatibility.
- Safety First: Ensure that the instrument air supply (or alternate operating gas, if used with GID) and any process lines connected to the transmitting element are fully isolated and depressurized before beginning work. Follow all Lockout/Tagout (LOTO) procedures.
- Mounting: The “-F” in the model code indicates field mounting, typically on a 2-inch vertical pipe or element yoke using the appropriate mounting kit. Ensure the controller is mounted level and securely. Its NEMA 3 enclosure rating means it’s weatherproof but should still be protected from direct, heavy weather where possible.
- Instrument Air/Gas Supply: Connect the clean, dry, and regulated air/gas supply (at the appropriate pressure, typically higher than 20 psi, for the IAS to regulate it down) to the controller’s supply port. The “IAS” option means the internal regulator will reduce this to 20 psi. Verify air/gas quality as per Foxboro’s specifications to prevent internal clogging or corrosion. The “AG” gauge will indicate the regulated supply pressure.
- Process Input Connection: Since this is a /PC (Pressure Receiver) model, connect the pneumatic input signal line (e.g., 3-15 psi from a remote transmitter) to the designated input port on the controller’s pressure receiver element. Ensure all fittings are tight and leak-free.
- Output Connection: Connect the controller’s 3-15 psi output line to the pneumatic actuator of the control valve or to a valve positioner if one is used.
- GID Specifics: If the “GID” option denotes a special gas service with a vent connection, ensure this vent is correctly piped to a safe, classified location as per plant standards and regulations. Do not vent hazardous gases directly into the atmosphere unless explicitly permitted and safe.
- Initial Power-up and Calibration: Once all connections are secure, slowly apply instrument air/gas pressure. Refer to the Foxboro 43AP instruction manual (e.g., MI 011-477) for specific procedures on initial setup, pointer alignment, and calibration of the input receiver and output range. This usually involves applying known input pressures and adjusting the zero and span for the indicator and output.
Maintenance recommendations: Regular and meticulous maintenance is essential for the reliability and accuracy of the 43AP-FA42C/PC-00GIDIAS-AG.
- Clean and Dry Air/Gas Supply: This is the single most critical maintenance aspect. Regularly check and drain instrument air filters (including the integral filter within the IAS). Contaminants (moisture, oil, particulates) are the leading cause of issues in pneumatic instruments. If using a process gas via the GID option, ensure its purity is maintained.
- Visual Inspection: Periodically inspect the controller’s exterior for corrosion, physical damage, loose connections, or cracked pneumatic tubing. Check the integrity of the enclosure seals. Monitor the “AG” gauge for stable supply pressure.
- Leak Checks: Systematically check all pneumatic connections (supply, input, output, internal tubing) for leaks using a soapy water solution (compatible with the operating gas, if GID applies). Even small leaks can degrade control performance and waste operating medium.
- Calibration Verification: Regularly verify the calibration of the pressure receiver and the controller’s output. This involves applying known input pressures (from a test pressure source) and checking the indicator’s accuracy and the output signal’s linearity and range. Adjustments should be made using the procedures outlined in the manual.
- Mechanical Integrity: Inspect the internal linkages, pivots, and springs for any signs of wear, excessive play, or stickiness. Ensure the flapper/nozzle assembly is clean and clear. The manual provides specific cleaning instructions for the restrictor and nozzle, often using a fine wire.
- Gauges: Check the functionality and accuracy of all local gauges (output gauge and IAS-AG gauge).
- Auto/Manual Transfer: Periodically test the bumpless transfer switch to ensure smooth and correct operation when switching between automatic and manual modes.
- GID Option Maintenance: If the GID option involves specific filters or vents for non-air gas service, ensure these are maintained according to Foxboro’s specific guidelines to ensure safe and proper operation.
- Documentation: Maintain detailed records of all maintenance activities, calibration results, and any replaced parts.
Given that this is a legacy product, parts may be scarce. Many users rely on reconditioned units and specialized instrument service companies for repairs and calibration.
