The FOXBORO 43AP-FA42C/PC-00 is a very specific configuration of the classic Foxboro 43AP Pneumatic Indicating Controller. The additional “/PC-00” suffix provides crucial details about the integrated measurement element and optional features.
Product Overview
The FOXBORO 43AP-FA42C/PC-00 is a Model 43AP Pneumatic Indicating Controller, manufactured by Foxboro (now part of Schneider Electric). This instrument is designed for the continuous measurement, indication, and control of a process variable using pneumatic (air pressure) signals. It compares the measured variable to a set point and generates a corresponding output air signal to operate a final control element, typically a control valve.
Let’s break down the full 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, often near the process.
- -A4: Specifies the control action as Proportional plus Integral (Reset), with an integral (reset) range of 0.01 to 50 minutes per repeat. This provides stable control and eliminates steady-state offset.
- -2: Refers to the Output Signal and Gauge: a 3 to 15 psi (pounds per square inch) output air signal, with a 30 psi output gauge for local indication of the output pressure.
- -C: Designates the Automatic Manual Internal Transfer Switching as “Bumpless” with a 2-position switch, balance gauge, and regulator. This ensures a smooth transition between automatic and manual control modes without disturbing the process.
- /PC: This is the key addition. It indicates that the controller is equipped with a Pressure Receiver (Bellows) measuring element. This means the controller’s input is a standard pneumatic pressure signal (e.g., 3-15 psi or 0-30 psi) from a separate transmitter that measures the actual process variable (like flow, level, or temperature) and converts it into a pressure signal. The bellows then translate this input pressure into a mechanical position that drives the controller’s mechanism.
- -00: This suffix typically denotes no additional optional features beyond those already specified in the main model code and the /PC element. Sometimes “00” can indicate a standard or default configuration.
This specific configuration makes it suitable for applications where a remote pneumatic transmitter provides the process measurement to the controller.
Technical Specifications
Main Features and Advantages
The FOXBORO 43AP-FA42C/PC-00 combines the inherent strengths of the 43AP series with the flexibility of a receiver input:
Pressure Receiver Input (/PC): This is a crucial feature. Instead of directly measuring a process variable (like pressure via a Bourdon tube), this controller receives a standard pneumatic signal (e.g., 3-15 psi) from a remote pneumatic transmitter. This allows the controller to be located away from the primary measurement point and facilitates the use of a wide range of Foxboro pneumatic transmitters for various process variables (flow, level, temperature, differential pressure, etc.).
Robust and Reliable Pneumatic Operation: Inherently immune to electrical noise, EMI, and RFI, making it safe and reliable for use in hazardous (explosion-proof) areas without complex barriers. Its mechanical design provides exceptional durability in harsh industrial environments.
Proven Field Performance: The 43AP series has a long track record of dependable operation, signifying its robustness and longevity in demanding industrial conditions.
Proportional plus Integral (Reset) Control: The “A4” control action provides both proportional and integral control, which is essential for stable process control and for eliminating any steady-state offset, ensuring the process accurately reaches and maintains its setpoint.
Bumpless Auto/Manual Transfer (“C” option): This critical feature allows operators to seamlessly switch between automatic and manual control modes without inducing sudden changes or disturbances in the process output, significantly improving operational stability.
Direct Local Indication: The controller provides a direct, mechanical indication of the process variable (derived from the input pressure), set point, and output signal. This allows operators to monitor the process status directly at the instrument in the field.
Field Mountable (“-F”): Designed for direct mounting on a pipe or yoke near the process or control valve, which can simplify pneumatic piping and potentially reduce signal lag.
Low Maintenance Requirements (Relative to some electronics): While requiring regular calibration and clean air, pneumatic instruments generally have fewer delicate electronic components, often leading to simpler troubleshooting and repair for trained personnel.
Application Field
The FOXBORO 43AP-FA42C/PC-00 is specifically tailored for applications within process industries where a pneumatic signal from a remote transmitter is used as the input to the controller. Its key application fields align with those of general pneumatic controllers but with the added flexibility of a receiver input:
Widely Applicable Across Process Industries:
- Chemical and Petrochemical Plants: Used in control loops for distillation columns (e.g., controlling reflux based on a flow transmitter’s output), reactors (e.g., temperature control from a temperature transmitter), heat exchangers, and separators.
- Oil and Gas Production and Refining: Employed in various control loops for pressure, flow, and level, especially in areas where explosion-proof equipment is mandatory or preferred due to the presence of flammable gases.
- Power Generation (Conventional Plants): Can be found in boiler control systems (e.g., drum level control from a differential pressure transmitter, steam flow control), and other auxiliary systems.
- 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.
- Food and Beverage Industry: For controlling temperatures, pressures, and flow rates in processing units, integrating with pneumatic transmitters for hygiene and safety.
