Temperature Modes- Dual Setpoint Fixed Deadband & Variable Deadband

| Overview

This feature introduces configurable temperature interaction modes across the CCU, portals, occupant applications, and supported devices. These modes define how heating and cooling desired temperatures are presented to users and how they respond to user adjustments.

The objective of this feature is to:

• Improve user comfort control experience

• Reduce user confusion in managing dual setpoints

• Maintain system stability and configure deadbands

• Provide flexible UI representations depending on device or application context

The implementation introduces building-level temperature control modes and zone/device-level temperature interaction modes.

| Feature Goals

The feature enables the following capabilities:

1. Support Dual Setpoint with Fixed Deadband control mode.

2. Retain existing Dual Setpoint with Variable Deadband behaviour.

3. Provide simplified single-setpoint interaction for occupants.

4. Provide Setpoint Offset interaction for relative comfort control.

5. Ensure all modes respect configured limits, deadbands, and HVAC control logic.

| Impact

The following devices and applications support this feature

Devices

• Occupant Mobile App

• MyStat

• MySense

• HyperStat Split

• MyStat Split

• TFCU

• SmartNode V2

Backend / Platform Components

• CCU

• Facilisight Portal

• Facilisight Assist

• Firmware (SmartNode V2)

| Temperature Modes Architecture

Temperature modes are configured at two levels.

| Building-Level Temperature Modes

Configured through:

• Facilisight Assist - Portals

• Installer Settings - CCU

These modes define how dual setpoints behave across the building.

Available options:

Default for new sites:
Dual Setpoint Fixed Deadband

| Zone / Device-Level Temperature Modes

Configured per device or zone.

Options:

Default:
Follow Site Temperature Mode

| Dual Setpoint Mode

Dual Setpoint with Fixed Deadband

In this mode, Heating Desired Temperature (HDT) and Cooling Desired Temperature (CDT) are linked.

Adjusting one setpoint automatically adjusts the other while preserving the configured deadband.

Example:

Example Interaction

Initial state:

HDT = 70°F
CDT = 74°F
Deadband = 4°F

User increases CDT to 76°F

Result:

HDT = 72°F
CDT = 76°F
Deadband = 4°F

Both setpoints move simultaneously.

| UI Behaviour

Temperature arc/slider displays:

• Current zone temperature

• HDT marker (red)

• CDT marker (blue)

• User intent limits

Thin lines represent:

• Maximum cooling limit

• Minimum heating limit

Limit Enforcement

Movement is allowed only if both setpoints remain within limits.

Example:

If CDT movement causes HDT to exceed heat max:

Movement is blocked.

Scenario 1 – Limit Violation

Initial:

HDT = 72
CDT = 76

User attempts:

CDT → 77

Expected shift:

HDT → 73

But:

Heat Max = 72

Result:

CDT remains 76

Scenario 2 – Overlapping Limits

If limits allow both movements:

HDT = 72 → 73
CDT = 76 → 77

Movement is allowed.

Scenario 3 – Unequal Deadbands

Example:

Heat DB = 3
Cool DB = 2

Total separation:

Deadband = 5

Setpoints are placed symmetrically:

HDT = 69.5
CDT = 74.5

| Dual Setpoint with Variable Deadband

This is the existing system behaviour.

Users can adjust HDT and CDT independently.

Constraint:

CDT - HDT >= Heat DB + Cool DB

Example:

Heat DB = 2
Cool DB = 2
Minimum separation = 4°F

Any configuration respecting this minimum is allowed.

| Mode Change Behaviour

Switching from Variable Deadband → Fixed Deadband

If existing schedules violate the fixed deadband rule, schedules are reset to default values.

Default Values

Schedule timings remain unchanged.