Description
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BrandFoxboro
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Model43AP-FA42C/PB-BA
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Product NamePneumatic Indicating Controller
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Place of OriginUnited States
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Customs HS Code9032890090
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Power Supply115 kPa to 155 kPa (16.7~22 psi)
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Dimensions240 mm × 200 mm × 160 mm
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Weight4.8 kg
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Operating Temperature-30 °C to +80 °C
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Storage Temperature-40 °C to +85 °C
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Warranty12 month
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Product Statusnew brand
Specifications of Foxboro 43AP-FA42C/PB-BA Pneumatic Indicating Controller
Model Code Definition
43AP: Pneumatic indicating controller series
F: Field mounting (pipe or yoke installation)
A4: PI (Proportional + Integral / Reset) control function
2: Standard 3~15 psi pneumatic output, fitted with built-in 0~30 psi output gauge
C: Onboard bumpless auto-manual transfer with balance gauge and integral air regulator
/PB-BA: Spiral pressure sensing element, 316 stainless steel wetted parts
Control Performance
Control mode: PI (Proportional plus Integral)
Integral time (reset): 0.01 min to 50 min per repeat
Proportional band: Steplessly adjustable
Input indication accuracy: ±0.5% of full span
Repeatability: 0.2% of full span
Dead band: 0.1% of full span
Signal & Air Supply
Supply air pressure: 20 psi ~ 30 psi (clean, dry instrument air)
Standard output signal: 3 ~ 15 psi
Air consumption: 0.5 m³/h (0.3 cfm) at normal operating state
Sensing Element
Element style: Spiral helical pressure element
Wetted material: 316 stainless steel
Process connection: 1/4 NPT female thread
Display & Setpoint
Scale form: Sector scale, effective length 150 mm (6 inch)
Scale marking: Black graduations against white background
Pointer: Fluorescent red pointer for PV and setpoint reading
Setpoint adjustment: Internal knob operation
Enclosure & Environmental Conditions
Housing material: Glass fiber reinforced polyester
Window: Shatterproof, UV-resistant polycarbonate
Protection grade: IEC IP53, NEMA Type 3
Operating ambient temperature: -29 °C ~ +66 °C
Structure: Weatherproof and anti-corrosion design
Mechanical & Mounting
Mounting type: Field pipe mount or yoke mount
Approximate weight: 4.8 kg (excluding sensing element assembly)
Surface finish: Gray polyester housing, textured blue door
Stress isolation: Control unit and sensing element fixed on a rigid steel base plate
Function Features
Built-in bumpless auto-manual transfer station
Balance gauge for output matching during auto/manual switchover
Reversible control action (direct / reverse action selectable on site)
Local visual display of process variable and setpoint
Pure pneumatic force-balance flapper-nozzle structure, no electronic components
Optional Accessories
Remote pneumatic setpoint input
Batch control function
Type 70 electric limit switches
Custom engraved nameplate
Working Principle of Foxboro 43AP-FA42C/PB-BA Pneumatic Indicating Controller
This field-mounted pneumatic PI controller features a spiral 316 stainless steel pressure sensing element and operates based on the flapper-nozzle pneumatic amplification and force-balance feedback principle. Process pressure applies force to the spiral sensing element, converting the pressure signal into mechanical displacement. This displacement is transferred to the differential linkage and compared against the mechanical position of the setpoint adjustment to produce a deviation signal. The deviation actuates the proportioning lever and alters the clearance between the flapper and nozzle. The resulting change in nozzle backpressure is amplified by a pneumatic relay to generate a standard 3~15 psi pneumatic output signal.
The output pressure is routed back to the proportional bellows to create proportional negative feedback, which restores the flapper-nozzle gap and fulfils proportional control. The integral reset bellows and restriction tank continuously integrate the deviation signal to remove steady-state offset and achieve proportional-plus-integral (PI) control.
This unit integrates a bumpless auto-manual transfer function. During mode switching, the balance gauge is used to align manual output with automatic output and prevent sudden output spikes. The controller requires clean, dry instrument air as its supply. It provides local pointer indication of the measured process pressure and transmits the 3~15 psi output to actuate control valves or other final control devices. The control action can be configured for direct or reverse action on-site to suit different process demands.
FAQ for Foxboro 43AP-FA42C/PB-BA Pneumatic Controller
Q: What is Foxboro 43AP-FA42C/PB-BA?
A: The Foxboro 43AP-FA42C/PB-BA is a 43AP series pneumatic controller, widely used for local process control in legacy industrial control systems. It delivers proportional plus integral (PI) control for pressure, temperature, flow and level loops.
Q: What is the standard signal range of the 43AP-FA42C/PB-BA?
A: It follows the standard 3-15 PSI pneumatic input and output signal range, which is the common industry standard for pneumatic control loops.
Q: What control modes does Foxboro 43AP-FA42C/PB-BA support?
A: This unit supports Proportional (P) and Proportional-Integral (PI) control modes. It can stabilize process variables without electrical power supply.
Q: What industries use the Foxboro 43AP-FA42C/PB-BA?
A: It is commonly applied in oil & gas, refineries, chemical plants, power stations and pulp & paper factories, especially for sites with explosion-proof requirements.
Q: Is the Foxboro 43AP-FA42C/PB-BA explosion-proof?
A: The 43AP series pneumatic controller has an intrinsically safe design. It works well in hazardous classified areas where electric instruments bring explosion risks.
Q: Is Foxboro 43AP-FA42C/PB-BA discontinued?
A: Yes, this Foxboro pneumatic controller has been end of manufacture. We supply surplus new stock and fully tested refurbished units for maintenance and replacement of old pneumatic control panels.
Q: Can I mount the 43AP-FA42C/PB-BA on a control panel?
A: Yes, it is designed for panel mounting. Standard cutout dimensions follow Foxboro 43AP series panel mounting specifications.
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