The FOXBORO 43AP-PA42C/PC00 (often seen as 43AP-PA42C/PC-00) refers to a specific configuration of the classic Foxboro 43AP Pneumatic Indicating Controller. This instrument is designed for process control using air pressure signals, specifically taking a pneumatic pressure signal as its input.
There’s a slight variation in the model code you provided compared to what’s most common. While “FA” typically indicates “Field Mounting,” the “PA” in your string might be a typo or an older/less common code. Assuming it functions similarly to “FA” in this context as a mounting type or a general series indicator, the primary characteristics of the controller remain clear based on the rest of the code. If “PA” specifically denotes something other than field mounting (e.g., panel mounting for a different series), that would change the physical installation, but the core functionality (control type, input, output) would still be driven by the A4, C, and PC codes. For this response, we’ll proceed assuming the “PA” refers to a mounting or general series variant consistent with the 43AP’s typical applications, which are generally field-mounted.
Product Overview
The FOXBORO 43AP-PA42C/PC00 is a Model 43AP Pneumatic Indicating Controller from 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 full model number:
- 43AP: Denotes the basic model, a Pneumatic Indicating Controller.
- -PA: (Assuming similar to -FA) Likely indicates a mounting style or series variant. In common 43AP models, “F” stands for Field Mounting. If “PA” signifies a different mounting (e.g., panel mount), it would affect physical installation. However, the 43AP is predominantly 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 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, 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.
- /PC00: This is the crucial part. 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-PA42C/PC00 controller. The “00” suffix typically denotes no additional standard optional features beyond the PC element.
This configuration is very common in pneumatic control systems, allowing the controller to receive inputs from a variety of pneumatic transmitters to control different process variables.
Technical Specifications
| Parameter Name | Parameter Value |
| Product Model | 43AP-PA42C/PC00 (often 43AP-FA42C/PC-00) |
| Manufacturer | Foxboro (now part of Schneider Electric) |
| Product Type | Pneumatic Indicating Controller with Pressure Receiver Input |
| Measurement Input | Standard pneumatic pressure signal (e.g., 3 to 15 psi) from a remote transmitter |
| Measuring Element | Internal Pressure Receiver (Bellows) |
| 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 (when input is a qualified pneumatic signal) |
| 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) (specific to this configuration) |
Main Features and Advantages
The FOXBORO 43AP-PA42C/PC00 brings together the robust characteristics of the 43AP series with the flexibility of a pneumatic receiver input:
Pneumatic Receiver Input (/PC00): This is a core feature. The controller accepts a standardized pneumatic signal (typically 3-15 psi) from a remote transmitter. This allows for diverse applications, as any process variable (temperature, flow, level, differential pressure, etc.) can be controlled as long as it’s first converted to a pneumatic signal by a suitable transmitter. This also allows for the controller to be located at a convenient, accessible point away from the primary measurement.
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 (as represented by the input pneumatic signal), 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 control valve or process area. This simplifies pneumatic piping and reduces potential signal lag.
Simpler Maintenance (for trained personnel): Compared to complex electronic systems, pneumatic instruments often have fewer delicate electronic components. While requiring regular calibration and clean air, troubleshooting and repair can sometimes be more straightforward for technicians familiar with pneumatic principles.
