Model T5221 Electro-Pneumatic Transducer from Rotork Fairchild

Model T5221 Electro-Pneumatic Transducer from Rotork FairchildWhen your application requires a very specific control system, look to the T5221 adjustable ratio I/P, E/P transducer. The T5221 transducer is an electro-pneumatic device that converts a DC current or voltage input signal to a proportional output pressure. This device is made up of four sections: the signal conversion section, the pneumatic section, the ratio section, and the booster section.

Operating Principles

The T5221 Transducer is an electro-pneumatic device that converts a DC current or voltage input signal to a proportional output pressure. This device is made up of four sections: the Signal Conversion Section, the Pneumatic Section, the Ratio Section, and the Booster Section.

The Signal Conversion Section (PC Board)accepts a DC current or voltage. This signal current is applied to a Coil, which creates a magnetic force that moves a Flexure Arm.

The Pneumatic Section operates as a force balance system. A Sapphire Ball floats inside a Nozzle and controls the output pressure by exhausting air supplied through an Orifice. This Sapphire Ball acts as a piston, exerting a force that is balanced against the force transferred to the Flexure arm by the Coil. Signal pressure from the Pneumatic Section is routed to the underside of the Signal Diaphragm in the Ratio Section. Signal pressure acting on the Signal Diaphragm transmits a force through the lever to the Control Diaphragm of the booster. The output pressure is a function of signal pressure times the ratio of lever arm lengths on either side of the Pivot.

The Booster Section supplies the unit's output pressure. At the set point, the lever Arm force acting on the top of the Control Diaphragm is balanced by the force due to the booster output pressure acting on the underside of the Control Diaphragm.

Features

Model T5221 Electro-Pneumatic Transducer Features

  • Shock and Vibration resistant - maintains consistent output pressure under shock and vibration conditions
  • Temperature compensation - provides stable operation over wide operating temperature ranges
  • Adjustable positive and negative bias - permits use with various final control elements
  • High output flow - meets requirements for most industrial control applications
  • Adjustable gain - allows a single device to cover most industrial and process control requirements

Specifications

Model T5221 Electro-Pneumatic Transducer Specifications

  • Output Range
    • Minimum: 10” (25.4 cm) Water Column to 50” (127 ------cm) Water Column
    • Maximum: 0-150 psig, [0-10 BAR], (0-1000 kPa)
  • Supply Pressure
    • Transducer: 20 + 2 psig, [1.5 + 0.15 BAR], (150 + 15 Kpa)
    • Ratio Relay:  250 psig, [17 BAR], (1700 kPa)
  • Air Consumption: 0.36 (0.6 m3/HR) Maximum
  • Output Capacity (SCFM): 40 (68 m3/HR) Maximum with 100 psig, [7 BAR], (700 kPa) Booster supply
  • Exhaust Capacity (SCFM): 5.5 (9.4 m3/HR) downstream pressure @ 5 psig, [.35 BAR], (35 kPa) above 20 psig, [1.5 BAR], (150 kPa) setpoint.
  • Supply Pressure Effect
    • Transducer: 1 % of Span for a + 2 psig, [.15 BAR],(15 kPa) change.
    • Ratio Relay:  Less than 0.1 psig, [.007 BAR], (.7 kPa) for 100 psig, [7 BAR], (700 kPa) change.
  • Ambient Temperature: -40° F to + 150° F, (-40° C to 65.5° C)
  • Materials of Construction
    • Body and Housing: Aluminum
    • Ball and Orifice: Sapphire
    • Nozzle: Stainless Steel

Dimensions

Model T5221 Electro-Pneumatic Transducer Dimensions

Rotork Fairchild Model T5221 Electro-Pneumatic Transducer Dimensions

Q & A

Q&A Section with Expand/Collapse Icons

Model T5221 Electro-Pneumatic Transducer Q & A

+ What does the T5221 do, and where is it typically used?
The T5221 converts a DC current or voltage input into a proportional pneumatic output pressure. It is designed for industrial process-control applications where precise pneumatic output is required (e.g., valve actuation, pneumatic actuators, or other air-driven final control elements). The “adjustable ratio” design and built-in booster make it especially useful when you need flexibility in output pressure and flow while maintaining accuracy.
 
+ What flexibility does the “adjustable ratio” feature provide, and why is that useful?
The T5221 includes a dedicated “Ratio Section” in addition to its signal conversion, pneumatic, and booster sections. This Ratio Section offers adjustable gain and adjustable positive or negative bias, which allows the same transducer to adapt to a wide variety of final control requirements. That flexibility means fewer different parts needed across varied applications — saving on inventory cost and simplifying system design.
+ What are the input signal options and output performance specifications?
The T5221 supports common industrial input signals (for example, 4–20 mA, 10–50 mA, 1–5 VDC, 1–9 VDC). It delivers a proportional pneumatic output, with high output flow and output capacity sufficient for most industrial control tasks. According to published specs, maximum flow capacity is around 40 SCFM (≈ 68 m3/hr) under supply pressure conditions.
 
+ Is the T5221 reliable under challenging environmental or installation conditions (e.g., vibration, temperature changes, mounting orientation)?
Yes. The T5221 is designed with shock and vibration resistance, temperature compensation for stable output over wide temperature ranges, and adjustable bias/gain for flexible application. This makes the device suitable for demanding industrial environments, where vibration, temperature variation, or non-ideal mounting might occur. 
 
 
+ Will the T5221 integrate easily into my existing control system or pneumatic network?
In most cases, yes. The T5221 accepts standard industrial control signals and outputs pneumatic pressure compatible with many pneumatic actuators or valves. Because of its adjustable ratio, bias, and gain — plus its high output flow — it can often be used in place of multiple different transducers, simplifying integration. However, proper supply air quality and correct installation (clean air, proper piping, and correct supply pressure) are important to ensure reliable long-term performance.
 


 

Downloads

Download Model T5221 Adjustable Ratio, E/P, I/P Pressure Transducer Datasheet

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