| Overview
Advanced AHU Controls with VAV Advanced Hybrid AHU is a system-level profile in the 75F system. The profile includes all the advanced control sequences in AHU as configurable options.
The focus shift has been towards larger, more advanced air handling units, as 75F started addressing the mid-market (buildings 50-250k sq.ft.). To address these larger AHUs, various techniques were introduced depending on what exists on the controller.
On built-up AHUs, we used an integrated panel to control the unit. The built-up AHU is one in which the equipment was often assembled in the field and does not have a factory-mounted unit controller, hence it required custom programming to operate correctly.
Advanced AHU Controls with VAV Advanced Hybrid AHU with configurable advanced control sequences can cut the amount of time required to commission such AHUs to a large extent. The already available IO ports in the CCU is an added advantage. With the CCU itself, we can perform the advanced AHU functions without adding additional hardware, but the profile also is provisioned to add up to 2 connect modules for any extra IO that might be needed for the AHU for control or monitoring purposes.
| How it Works
Similar to other system profiles, the VAV Advanced Hybrid AHU v2 is also influenced by the zone loads, where based on the zone load the system equipment would provide heating or cooling for more information refer to VAV Advanced Hybrid AHU. It also is capable of controlling these advanced devices based on the Supply Air Temperature (SAT), and Duct Static Pressure (DSP).
Supported With Upto:
- 5 Stages of Load-Based Cooling
- 5 Stages of Load-Based Heating
- 5 Stages of Load-Based Fan
- 5 Stages of Supply Air Temperature (SAT)-Based Cooling
- 5 Stages of Supply Air Temperature (SAT)-Based Heating
- 5 Stages of Duct Static Pressure (DSP)-Based Fan
- Humidifier, Dehumidifier, Fan and Occupied enable
- AHU Fresh Air Fan Run Command
| Wiring
| Configuration
The configuration screen for the VAV Advanced Hybrid AHU v2 is accessed from the System Configuration option, as below.
The configuration screen for the VAV Advanced Hybrid AHU v2 displays, as below.
| Configuration Parameters CM/CCU
Sensor Bus Address Setting Configuration, based on sensors Used | |||
Parameter | Purpose | Default Value | Values in the Drop-Down List |
Address 0 |
When a sensor is used for Temperature, Humidity, Occupancy, CO2 & Pressure sensing |
Not Connected |
For Temperature:
For Humidity:
For Occupancy:
For CO2:
For Pressure:
|
Address 1 | When a sensor is used for Temperature, Humidity, Occupancy, and CO2 sensing | Not Connected | |
Address 2 | When a sensor is used for Temperature, Humidity, Occupancy, and CO2 sensing | Not Connected | |
Address 3 | When a sensor is used for Temperature, Humidity, Occupancy, and CO2 sensing | Not Connected |
Analog Input Configuration, based on the Parameter/sensor | |||
Parameter | Purpose | Default Value | Values in the Drop-Down List |
Analog Input 1 | When a type of sensing is enabled at the Analog Input port of the CM | Duct Static Pressure 2_2 |
|
Analog Input 2 | When a type of sensing is enabled at the Analog Input port of the CM |
Return Air CO2
|
Thermistor Input Configuration, based on the Parameter/sensor used | |||
Parameter | Purpose | Default Value | Values in the Drop-Down List |
Thermistor 1 | When a type of sensing is enabled at the Analog Input port of the CM | Supply Air Temperature 1 |
|
Thermistor 2 | When a type of sensing is enabled at the Analog Input port of the CM | Emergency Shut Off NO |
Relay Based Outputs | |||
Parameter | Purpose | Default Value | Values in the Drop-Down List |
Relay 1 |
To enable staged conditioning control |
SAT Cooling Stage 1 |
|
Relay 2 |
To enable staged conditioning control |
SAT Cooling Stage 2 | |
Relay 3 | To enable staged conditioning control | Fan Pressure Stage 1 | |
Relay 4 | To enable staged conditioning control | SAT Heating Stage 1 | |
Relay 5 | To enable staged conditioning control | SAT Heating Stage 2 | |
Relay 6 | To enable staged conditioning control | Fan Pressure Stage 2 | |
Relay 7 | To enable staged conditioning control | Humidifier Enable | |
Relay 8 | To enable staged conditioning control | Dehumidifier Enable |
Analog Based Outputs | |||
Parameter | Purpose | Default Value | Values in the Drop-Down List |
Analog Out 1 |
To enable modulating conditioning control |
Pressure Based Fan Control |
|
Analog Out 2 | To enable modulating conditioning control | Sat Based Cooling Control | |
Analog Out 3 | To enable modulating conditioning control | Sat Based Heating Control | |
Analog Out 4 | To enable modulating conditioning control | CO2 Based Damper Control |
For analog-based output configuration, additional parameters need to be configured, as below.
For Pressure based Fan Control:
For SAT based Cooling & Heating Control:
For CO2 based Damper Control:
For Load based Cooling, Heating, & Fan Control:
| Adding a Connect Module
A connect module can be added to the profile when required.
- Click the Add Connect Module to add a connect module to the profile to provision additional control & monitoring ports to the profile.
The Connect module configuration screen displays, as below.
| Configuration Parameters Connect Module
Sensor Bus Address Setting Configuration, based on sensors Used | |||
Parameter | Purpose | Default Value | Values in the Drop-Down List |
Address 0 |
When a sensor is used for Temperature, Humidity, Occupancy, CO2 & Pressure sensing |
Not Connected |
For Temperature:
For Humidity:
For Occupancy:
For CO2:
For Pressure:
|
Address 1 | When a sensor is used for Temperature, Humidity, Occupancy, and CO2 sensing | Not Connected | |
Address 2 | When a sensor is used for Temperature, Humidity, Occupancy, and CO2 sensing | Not Connected | |
Address 3 | When a sensor is used for Temperature, Humidity, Occupancy, and CO2 sensing | Not Connected |
Relay Based Outputs | |||
Parameter | Purpose | Default Value | Values in the Drop-Down List |
Relay 1 |
To enable staged conditioning control |
Load Cooling Stage 3 |
|
Relay 2 |
To enable staged conditioning control |
Load Heating Stage 3 | |
Relay 3 | To enable staged conditioning control | Load Fan Stage 3 | |
Relay 4 | To enable staged conditioning control | Load Cooling Stage 4 | |
Relay 5 | To enable staged conditioning control | Load Heating Stage 4 | |
Relay 6 | To enable staged conditioning control | Load Fan Stage 4 | |
Relay 7 | To enable staged conditioning control | Load Cooling Stage 5 | |
Relay 8 | To enable staged conditioning control | Load Heating Stage 5 |
Analog Based Outputs | |||
Parameter | Purpose | Default Value | Values in the Drop-Down List |
Analog Out 1 |
To enable modulating conditioning control |
Load Based Cooling Control |
|
Analog Out 2 | To enable modulating conditioning control | Load Based Fan Control | |
Analog Out 3 | To enable modulating conditioning control | Load Based Heating Control | |
Analog Out 4 | To enable modulating conditioning control | Composite Signal |
For analog-based output configuration under the connect module, additional parameters need to be configured, as below.
For Load based Cooling, Heating, & Fan Control:
For Composite Signal Control:
For CO2 based Damper Control:
Universal Input Configuration Parameters
Thermistor/ Digital Based Universal Inputs |
|||
Parameter |
Purpose |
Default Value |
Values in the drop-down list |
Universal-in1 |
To enable Digital/Analog/Thermistor based input sensing |
Supply Air Temperature |
|
Universal-in2 |
To enable Digital/Analog/Thermistor based input sensing |
Mixed Air Temperature |
|
Universal-in3 |
To enable Digital/Analog/Thermistor based input sensing |
Outside Air Temperature |
|
Universal-in4 |
To enable Digital/Analog/Thermistor based input sensing |
Duct Static Pressure (0-2") |
|
Universal-in5 |
To enable Digital/Analog/Thermistor based input sensing |
Current TX (0-50Amps) |
|
Universal-in6 |
To enable Digital/Analog/Thermistor based input sensing |
Condensate Overflow (N/O) |
|
Universal-in7 |
To enable Digital/Analog/Thermistor based input sensing |
Filter Status (N/O) |
|
Universal-in8 |
To enable Digital/Analog/Thermistor based input sensing |
Generic 1-100KOhm |
Configure the required parameters under the CM & Connect Module Configurations
- Click SET to confirm the profile configurations.
Possible Error:
If the sensors are not selected in a sequential order the following warning message displays.
If the same sensor type is configured for two different sensor addresses/ Analog inputs or thermistor inputs. The following error message displays.
If analog outs for the staged controls (relay-based SAT cooling/heating /Static Pressure) are not enabled the following error message displays.
The profile configurations are confirmed and saved successfully message displays.
The configured VAV Advanced Hybrid AHU v2 profile can be visualized on the CCU system screen, as below.
| Algorithm & Operation
Zone Load Based Controls:
The table below talks about the algorithm and operation of the VAV Advanced Hybrid AHU v2 profile, when the load-based controls are configured for in the profile.
Control | Control Type | Operation |
Cooling Load Control | Relay Based | The cooling control stages are enabled and ramped up as the systemCoolingLoopOutput changes from 0% to 100% depending on the load conditions. |
Cooling Load Control | Analog Based |
The cooling control signal modulates between analogOutXAtMinCooling and analogOutXAtMaxCooling as the systemCoolingLoopOutput changes from 0% to 100% depending on the load conditions. |
Heating Load Control | Relay Based | The Heating control stages are enabled and ramped up as the systemHeatingLoopOutput changes from 0% to 100% depending on the load conditions. |
Heating Load Control | Analog Based |
The Heating control signal modulates between analogOutXAtMinHeating and analogOutXAtMaxheating as the systemHeatingLoopOutput changes from 0% to 100% depending on the load conditions. |
Load Fan Control | Relay Based | The Fan control stages are enabled and ramped up as the system Cooling/Heating Loop Output changes from 0% to 100% depending on the load conditions. |
Load Fan Control | Analog Based |
The Fan control signal modulates between analogOutXAtMinFan and analogOutXAtMaxFan as the system Cooling/Heating Loop Output changes from 0% to 100% depending on the load conditions. |
Supply Air Temperature (SAT) Based Controls:
The table below describes the algorithm and operation of the VAV Advanced Hybrid AHU v2 profile when the Supply Air Temperature controls are configured for in the profile.
Control | Control Type | Operation |
SAT Cooling Control | Relay Based |
|
SAT Cooling Control | Analog Based |
|
SAT Heating Control | Relay Based |
|
SAT Heating Control | Analog Based |
|
Duct Static Pressure (DSP) Based Controls:
The table below describes the algorithm and operation of the VAV Advanced Hybrid AHU v2 profile when the duct static-based fan controls are configured for in it.
Cooling Side:
Control | Control Type | Operation |
Pressure Fan Control | Relay Based |
|
Pressure Fan Control | Analog Based |
|
Heating Side:
Control | Control Type | Operation |
Pressure Fan Control | Relay Based |
|
Pressure Fan Control | Analog Based |
|
Composite Controls:
Control | Control Type | Operation | ||||||
Composite Control | Relay Based |
Example:
|
Fan Enable:
Whenever heating or cooling conditioning is in action the Fan enabled relay is turned on.
During unoccupied hours relay will turn on only if there is a call for cooling/heating - this includes economizing action)
Occupied Enable:
This relay will be on whenever the building is scheduled for occupancy or systemStaticPressureLoopOutput > 0.
During unoccupied hours relay will turn on only if there is a call for cooling/heating - this includes economizing action)
Humidifier:
The humidifier is turned on whenever the humidity level for the system drops below the targetMinInsideHumidty set on the systems page.
The humidifier will be turned off after being turned on when the humidity goes humidityHysteresis above the targetMinInsideHumidty.
Humidity control will not be maintained during UNOCCUPIED or VACATION modes. Even during pre-conditioning, emergency conditioning, and auto-forced occupied, the humidifier is not operational.
| Post Configuration
The zone paired with VAV Advanced Hybrid AHU is displayed in the CCU as below:
You can see widgets configured in the heatmap pages in the portals as below:
| Equip Graphics
Equipment graphics is available for all the terminal profiles. It provides a graphical representation of system-level equipment and enables monitoring of key point parameters associated with terminal profiles.
The highlighted list of points is predefined for visualization alongside the graphic for the respective profile.
| Feature Availability Versions
Feature | Hardware/Firmware | Version |
The VAV Advanced Hybrid AHU V2 system support |
CM | 3.53 and above. |
The VAV Advanced Hybrid AHU V2 system support |
Connect Module | 1.4 and above |
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