Configured for precise process variable regulation in pneumatic control loops, the YOKOGAWA 43AP-FA42C (43AP Pneumatic Indicating Controller) provides direct physical/electrical execution. This hardware component serves as the primary pneumatic controller utilized to execute proportional and integral control logic across field-mounted process platforms.

Suffix Breakdown & Model Matrix

• 43AP: Indicating Controller series baseline.
• -F: Mounting configuration for field installation (Pipe or Yoke).
• A4: Control mode featuring Proportional plus Integral (Reset) action, adjustable from 0.01 to 50 minutes per repeat.
• 2: Output signal range of 3-15 psi with an integrated 30 psi system gauge.
• C: Automatic/Manual internal transfer switching functionality, incorporating bumpless transition, 2-position switch, balance gauge, and air regulator.

Hardware Specifications

Industrial Control and Actuator Loop Feedback

The 43AP-FA42C operates via mechanical bellows and nozzle-flapper systems to translate process variable measurements into calibrated pneumatic output signals. The proportional plus integral control architecture enables the unit to minimize steady-state error in flow, pressure, or temperature regulation. The integrated bumpless transfer mechanism ensures that when switching between automatic and manual modes, the output pressure remains stable, preventing process upsets in sensitive industrial loops.

Frequently Asked Questions

Q: What is the primary purpose of the bumpless transfer feature in this controller?

A: The bumpless transfer feature prevents sudden changes in the output signal (3-15 psi) when the operator toggles between automatic control and manual override, ensuring the process remains stable during manual interventions.

Q: Can the proportional and integral settings be adjusted independently on this unit?

A: Yes, the 43AP-FA42C is equipped with internal pneumatic adjustments that allow the technician to calibrate the gain and reset rate to match the process dynamics of the specific loop.

Field Installation Guidelines

• Ensure the controller is mounted securely to the designated pipe or yoke using the appropriate hardware to prevent vibration-induced calibration drift.
• Connect the air supply to the regulator port, ensuring the input pressure is maintained at the required level to operate the pneumatic control logic.
• Check all pneumatic tubing connections for leaks using a bubble solution; tighten fittings as necessary to ensure signal integrity.
• Align the local indicator pointer with the process variable transmitter output before enabling the automatic control mode.
• Regularly drain the air filter-regulator associated with the pneumatic supply to prevent moisture and oil accumulation from affecting the nozzle-flapper orifice.