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Programming Guide

_{Source: Intuition-6 Instruction Manual Rev. H, Pages: 65–90} This section covers all control algorithms available on the Intuition-6 controller. Each relay output can be programmed for a specific control mode based on your application requirements.

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Common Parameters

These parameters appear in most relay control modes:

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Duty Cycle

Duty cycling prevents overshoot in applications where sensor response to chemical additions is slow. Set a period and percentage to limit how long the relay can be on during each cycle. Example: 5-minute period with 50% duty cycle = relay on maximum 2.5 minutes per 5-minute period

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Interlocks and Activates

• Interlock — Select relays or digital inputs that will turn OFF this relay when active
• Activate With — Select relays or digital inputs that will turn ON this relay when active

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Basic Control Modes

Use these modes for simple on/off or range-based control.

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On/Off Control

Turns the relay on and off based on a set point and deadband. The relay activates at the set point and deactivates at the set point minus the deadband. Parameters:

• Set Point — Value at which relay activates
• Deadband — Difference between on and off points
• Direction — Force Higher or Force Lower

Example: Cooling Tower Blowdown

• Input: Conductivity sensor
• Set Point: 2000 µS/cm
• Deadband: 25 µS/cm
• Direction: Force Lower

The bleed valve opens at 2000 µS/cm and closes at 1975 µS/cm (2000 - 25).

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Dual Set Point Control

Uses two set points to control a relay—commonly used for pH control where you need to stay within a range. Modes:

• In Range — Relay on when value is between set points (deadbands outside range)
• Out of Range — Relay on when value is outside set points (deadbands inside range)

Example: pH Band Control (In Range)

• Set Point 1: 10 pH
• Set Point 2: 4 pH
• Deadband: 0.1

The relay runs when pH is between 3.9 and 10.1, keeping pH in the normal operating range.

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Manual Mode

The relay activates only when placed in Hand mode or when activated by another channel. Use this for pumps that need to be triggered by other relays.

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Timer-Based Control Modes

Use these modes for scheduled or duty-cycle control.

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Timer Control

Activates the relay at scheduled times. Supports up to 10 timed events per day with Daily, Weekly, 2-Week, or 4-Week repetition. Key Behaviors:

• If a second timer starts while first is active, the second is ignored (Event Skipped alarm)
• Interlocks override relay control but don’t affect timer scheduling
• Add Last Missed — If enabled, missed events run immediately after interlock clears

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Percent Timer

Cyclical on/off operation regardless of sensor input. Parameters:

• Sample Period — Total cycle time
• Feed Percentage — Percentage of cycle time relay is active

Example: 5-minute period at 50% = 2.5 minutes on, 2.5 minutes off, repeating continuously

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Biocide Timer

Scheduled chemical addition with optional pre-bleed and bleed lockout. Designed for alternating oxidizing and non-oxidizing biocide programs. Parameters:

• Event schedule (up to 10 events)
• Duration — Time relay is on
• Bleed — Select bleed relay to coordinate with
• Prebleed Time — Fixed time bleed runs before biocide
• Prebleed To — Conductivity target before biocide starts
• Bleed Lockout — Time bleed is disabled after biocide completes

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Probe Wash

Activates the relay at scheduled times to clean sensors. Control outputs using the sensor are held or disabled during cleaning. Parameters:

• Event schedule
• Sensor Mode — Hold (maintain last reading) or Disable (turn off outputs)
• Hold Time — Time after wash ends before resuming normal readings

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Spike Control

Provides a baseline control set point with periodic “shock” events at a higher set point. Common for chlorine disinfection. Parameters:

• Set Point — Normal operating target
• Spike Set Point — Target during spike events
• Onset Time — Delay before spike duration timer starts
• Event schedule and duration

Onset Time Behavior:

• If set to zero, spike duration starts immediately
• If set to a value, duration timer starts when either:
  • Spike set point is reached, OR
  • Onset time expires

Example: Weekly Chlorine Shock

• Normal Set Point: 1000 mV ORP
• Spike Set Point: 1200 mV ORP
• Duration: 10 minutes
• Schedule: Every Monday at 8:00 AM

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Proportional Control Modes

Use these modes when output should scale with process error.

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Time Proportional Control

Relay on-time is proportional to how far the process value is from set point. The pattern is cyclical—the controller evaluates once per sample period and calculates appropriate on-time. Parameters:

• Set Point — Target value
• Proportional Band — Distance from set point where output reaches 100%
• Sample Period — Evaluation interval

Example:

• Set Point: 1000 µS/cm
• Proportional Band: 200 µS/cm
• Sample Period: 20 minutes

At 1100 µS/cm (50% of proportional band), relay on for 10 minutes, off for 10 minutes. At 1050 µS/cm (25% of proportional band), relay on for 5 minutes, off for 15 minutes.

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Pulse Proportional Control

Requires opto (solid state) relay output. The relay pulses at a rate proportional to how far the value is from set point. Used with pulse-input metering pumps. Parameters:

• Set Point — Value where pump runs at minimum rate
• Proportional Band — Distance from set point for 100% output
• Min Output % — Minimum pulse rate percentage
• Max Output % — Maximum pulse rate percentage
• Max Rate — Maximum pulses per minute (pump dependent, typically 360)
• Direction — Force Higher or Force Lower

Understanding Force Higher vs Force Lower: Example: pH Control Adding Acid (Force Lower)

• Set Point: 7.0 pH
• Proportional Band: 4.0
• At pH 11 (set point + band): Pump at 100%
• At pH 7: Pump stops

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PID Control

Requires opto relay OR analog output card. Standard Proportional-Integral-Derivative control for applications requiring precise setpoint maintenance. Available Forms:

• Standard Form — Industry-standard time-based parameters
• Parallel Form — All parameters as gains

Standard Form Parameters:

• Gain (Kp) — Response to error magnitude
• Integral Time (Ti) — Response to accumulated error over time
• Derivative Time (Td) — Response to rate of error change

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Flow-Based Control Modes

Use these modes to drive feed based on flow measurements.

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Flow Timer

Activates relay for a fixed time after a set volume passes through flow meter(s). Parameters:

• Feed Duration — Time relay stays on
• Accumulator Volume — Volume that triggers feed
• Flow Input — Primary flow meter
• Flow Input 2 — Optional second flow meter (volumes summed)

Example: Feed inhibitor for 1 minute after every 50 gallons of makeup water

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Flow Proportional (PPM Mode)

Requires opto relay or analog output. Continuously adjusts output to maintain a target PPM based on measured flow rate. Parameters:

• Target — Desired PPM concentration
• Pump Capacity — Maximum pump flow rate
• Pump Setting — Stroke length setting (%)
• Specific Gravity — Product specific gravity
• Flow Input — Flow meter source
• Cycles Input — Virtual input for cycles of concentration (optional)
• Low Cycles Limit — Minimum cycles before limiting output

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Flow Meter Ratio Control

Volumetric cycles of concentration control. For every X gallons of makeup, bleed Y gallons. Parameters:

• Accumulator Volume — Makeup volume to trigger bleed
• Bleed Volume — Volume to bleed before stopping
• Makeup Meter(s) — Up to 2 makeup water meters
• Bleed Meter(s) — Up to 2 bleed water meters

Example:

• Accumulator Volume: 1000 gallons
• Bleed Volume: 100 gallons
• Result: 10:1 cycles of concentration

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Volume Control Mode (PPM with PosiFlow)

Requires feed monitor input. Like Flow Timer, but uses feed monitor pulses instead of fixed time to confirm chemical delivery. Parameters:

• Target PPM
• Specific Gravity
• Accumulator Volume
• Flow Input(s)

The controller calculates required pump strokes and confirms delivery via feed monitor pulses.

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HVAC/Boiler Control Modes

Use these modes for cooling tower and boiler-specific control patterns.

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Bleed & Feed

Two relays activate simultaneously—typically bleed valve and inhibitor pump. When bleed reaches timeout or conductivity target, both relays stop. Inhibitor can have a separate feed time limit. Configuration:

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Bleed then Feed

Inhibitor feeds for a percentage of bleed time, starting after bleed stops. Parameters:

• Feed Percentage — Percent of bleed time for feed relay
• Bleed — Select the bleed relay

Example: If bleed runs 4 minutes at 50% feed percentage, inhibitor runs 2 minutes after bleed completes.

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Intermittent Sampling

For boilers with proportional blowdown on a trapped sample. Two operating modes:

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Trapped Sampling Enabled (Time-Based)

Samples periodically, traps sample, blows down for proportional time based on conductivity. Sequence:

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Trapped Sampling Disabled (Conductivity-Based)

Samples periodically, blows down until conductivity reaches setpoint minus deadband. Key Difference: No Hold Time or proportional calculation—direct conductivity control.

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Advanced Control Modes

Use these modes for multi-relay coordination or specialized sequencing.

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Lead/Lag Control

Coordinates multiple relays (up to 6) for capacity staging or backup redundancy. Parameters:

• Lead — First relay to activate
• Wear Leveling — Rotate lead relay to equalize run time
• Wear Cycle Time — How often to rotate
• Activation Mode — How lag relays activate
• Set Point / Set Point 2 — Stage-in and stage-out thresholds
• Delay Time — Time between stage changes

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Dual Switch Control

Activates based on two digital input states—for applications requiring multiple conditions.

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Counter Timer

Activates relay after a set number of pulses from a counter input, then runs for a fixed duration. Parameters:

• Feed Duration — Time relay stays on
• Accumulator Setpoint — Pulses required to trigger
• Input — DI Counter source

Example: Run relay for 1 minute after every 6 pulses (with 2 units/pulse = 3 contacts)

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Volumetric Blending

Mixes two liquid streams at a fixed ratio using a diverter valve. Optional disturbance input adjusts the blend ratio. Parameters:

• Accumulator Volume — Flow with relay OFF (source 1)
• Blend Volume — Flow with relay ON (source 2)
• Flow Input — Flow meter
• Disturbance Input — Optional adjustment factor

Example: Mix 100 gallons city water (relay off) with 300 gallons reclaimed water (relay on)

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Disturbance Control

Disturbance control allows a second input to modify the control set point or output rate.

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Types of Disturbance Control

• On/Off Disturbance — Disturbance multiplies the set point
• Pulse/Analog Disturbance — Disturbance affects output rate
• Trigger Multiply — Primary controls normally; both control when triggered
• Trigger Disturbance — Switch between primary and disturbance control

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Configuring Disturbance

Set up the disturbance in a Virtual Input: Parameters:

• Min Disturbance — Lower threshold
• Max Disturbance — Upper threshold
• Value at Min Disturbance — Multiplier at min (typically 1.0)
• Value at Max Disturbance — Multiplier at max
• Disturbance Input — Sensor providing disturbance value

Example: Corrosion-Based Inhibitor Control

• Primary Input: PTSA sensor (100 ppm set point)
• Disturbance Input: Corrator (4-6 mils/yr range)
• Multiplier: 1.0 at 4 mils/yr, 1.25 at 6 mils/yr

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Virtual Inputs

Virtual inputs are calculated values based on physical sensor inputs.

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Calculation Types

• Difference — Input 1 minus Input 2
• Ratio — Input 1 divided by Input 2 (useful for cycles of concentration)
• Total — Input 1 plus Input 2
• % Difference — (Input 1 - Input 2) / Input 1 (useful for RO % rejection)

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Redundant Sensors

Provides sensor backup with three modes:

• Primary/Backup — Use Input 1 unless it fails
• Minimum Value — Use whichever sensor reads lower
• Maximum Value — Use whichever sensor reads higher

A Deviation Alarm triggers when sensors differ by more than a set amount.

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Raw Value

Logs the uncalibrated sensor signal for troubleshooting—useful for verifying sensor health.

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Analog Outputs

Use these options to configure 4-20 mA output behavior.

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Retransmit Mode

Outputs a 4-20 mA signal proportional to a sensor input. Used to send readings to PLCs, recorders, or other devices. Parameters:

• 4 mA Value — Sensor reading that produces 4 mA
• 20 mA Value — Sensor reading that produces 20 mA
• Input — Source sensor or virtual input

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Proportional Control Mode

Like Pulse Proportional but outputs 4-20 mA instead of pulses. For controlling 4-20 mA input pumps or valves.

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PID Control Mode

Standard PID control with 4-20 mA output.

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Flow Proportional Mode (PPM)

Like pulse flow proportional, but adjusts 4-20 mA output to maintain target PPM.

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Quick Reference

Use this section as a fast lookup when selecting control modes.

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Control Mode Selection by Application

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Output Types and Compatible Modes

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Sources

Intuition-6 Instruction Manual Rev. H

Pages 65–90 • February 2024