Parker Air Preparation Products | FRLs | Proportional Regulator Glossary

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Hysteresis - The mechanical limits of accuracy of the unit. The regulator cannot be adjusted within the inherent mechanical limits of the design.

Dead Band - The minimum limit of accuracy at which the regulator is set for normal operation. This band must be equal to, or exceed, the inherent design limits of the regulator or the hysteresis band.

Proportional Band - The band used for setting reaction sensitivity of the regulator. The regulator senses the excursion from the set pressure and adjusts response in relation to the degree of excursion beyond the dead band. This band must exceed the dead band of the unit.

Proportional Effect - The speed at which the unit approaches P2 (secondary pressure).

Sensitivity - The smallest change in the control signal or feedback signal, to cause a change in regulated output pressure.

Repeatability - A measurement of how consistently the unit can reproduce an output pressure in relation to a specific set pressure.

Linearity - A measure of how closely the relationship of output pressure vs. the control signal deviates from a straight line function.

PNP Output - Referred to as a "Sourcing" open collector transistor output where the voltage sources towards 24VDC when activated.

NPN Output - Referred to as a "Sinking" open collector transistor output. The output sinks towards 0VCD when activated.

Warning Triangle WARNING: These products can expose you to chemicals including lead and/or DEHP and/or carbon black, which are known to the State of California to cause cancer or birth defects or other reproductive harm.  For more information go to

Parker Air Preparation

Global Air Prep
  • Modular design allows for quick component change - no need to disconnect piping
  • Can be used without modular connectors using existing piping
Prep-Air II
  • Wide selection of sizes and options
  • Proven design, widely used

Stainless Steel FRLs

  • Suitable for most corrosive environments

Precision Regulators

  • Flows to 150 SFFM
  • Pressures to 500 PSIG

Electronic Proportional Regulators

  • All controls on the same face
  • Highly visible LED Display
  • Modular Mounting