Proportional Control Mode

Optimizing Chemical Control with Proportional Dosing for Smaller Pools - Image

Optimizing Chemical Control with Proportional Dosing for Smaller Pools

Proportional Control is recommended for small bodies of water to prevent overfeeding when using oversized chemical feeders. In this mode:

  • The outlet relay turns ON and OFF at a rate that gradually decreases as the chemical level approaches the setpoint.
  • The relay operates at 100% ON during a 100-second cycle at the outer edge of the Progressive Zone, and slows to 0% ON exactly at the setpoint.

(See schematic for visual representation.)

How It Works

  • Within the Progressive Zone, the controller adjusts dosing speed — slower and more precise as the target is neared.
  • Outside the Progressive Zone, the controller switches back to standard ON/OFF control.
  • A wider Progressive Zone means slower but smoother adjustment toward the setpoint.
  • A narrower Progressive Zone leads to faster response, approaching standard ON/OFF behavior.

Note: Longer safety time limits may be needed in Proportional Mode because the slower feed rate can extend the time to reach the setpoint.

Calculate your proportional zone …

Key Benefits

  • Provides more precise chemical control compared to basic ON/OFF control,
  • Reduces risk of overfeeding, especially in smaller pools or spas.

Deadband and Progressive Zone Control - Image

Deadband and Progressive Zone Control

Deadband Zone

In all three automatic control modes — ON/OFF, Proportional, and 4-20 mA — the controller utilizes a deadband zone around the setpoint to prevent relay chattering (rapid turning on and off).

  • The deadband is defined as a percentage of the setpoint and can be adjusted by the operator via the DEADBAND screen.
  • How it works: The outlet remains activated until the sensor reading reaches the setpoint, at which point it is deactivated.
  • To re-activate the relay, the reading must move outside of the deadband zone, eliminating the impact of small fluctuations.

Progressive Zone

The Progressive Zone surrounds the setpoint and controls outlet activation based on how far the sensor reading is from the setpoint value.

  • Outside the Progressive Zone, the outlet runs 100% of the time.
  • As the sensor reading approaches the setpoint, the outlet activation decreases progressively, ultimately reaching 0% once it enters the deadband zone near the setpoint. (See schematic for visual representation.)

Benefits

  • Deadband prevents unnecessary cycling, making the system more stable.
  • Progressive Zone enables smooth control and prevents over-correction, ensuring precision near the setpoint.

CLOSE