greenBOX Nxt Quick Calibration Guide
Table of Contents
Important Considerations Before Calibration
What You Need for Ventilation System Calibration
Step 1: Calibration Air Velocity Measurement at Each Gate
Step 2: Calibration of Air Velocity & Air Volume Reading in the Main Duct
Step 3: Adjusting Fan Minimal and Maximal Speed by Utilizing “Air Volume Surplus"
Achieving Optimal Ventilation Performance Through Calibration
Now that your Ecogate system is fully installed—including workstations, gates, and VFDs—and the software is set up, it’s time to fine-tune your system for peak performance.
Calibration ensures that:
✔ Each active workstation receives the design air volume, whether it’s a single workstation or the maximum number your system supports.
✔ Minimum transport air velocity is maintained throughout the ductwork to prevent material buildup.
Just like the initial setup, calibration is designed to be straightforward. The greenBOX software features an intuitive, user-friendly interface—similar to a smartphone—making the process simple and efficient.
Best of all, the greenBOX software is standardized across all systems, from small workshops to large industrial facilities. It has been thoroughly tested in real-world environments, so you can trust its reliability and effectiveness.
Important Considerations Before Calibration
1. The Duct System Must Be Fully Installed and Connected
Calibration should only be performed after the duct system is completely installed and connected to all workstations.
If ductwork is modified after calibration, airflow resistance will change, making previous calibration efforts invalid.
New shops: Be aware that dust collection systems are sometimes installed before workstations. If workstations are added later, recalibration will be required.
2. No Dust Should Be Present During Calibration
The pitot tube used for air velocity measurement can become clogged with dust, leading to inaccurate readings.
Calibration must be performed when no material is moving through the duct system—schedule downtime accordingly.
The time required for calibration depends on:
The number of gates in the system
The accessibility of workstations and the main duct
What You Need for Ventilation System Calibration
Calibration Tools and Equipment
To accurately calibrate your ventilation system, you’ll need to measure air velocities at each gate (drop) and within the main duct. We recommend using a high-quality air velocity meter, such as the Fluke 922, paired with appropriately sized pitot tubes—a shorter one for gates and a longer one for reaching across the main duct's diameter.
Required Tools & Equipment
✔ Fluke 922 Air Velocity Meter with fresh AA batteries
✔ Small pitot tube for measuring air velocity at gates
✔ Long pitot tube for measuring air velocity in the main duct (For a 60” main duct, use a 60” pitot tube or longer)
✔ Battery-powered drill with a step bit for creating pitot tube access points
✔ Tape or plastic covers to seal holes in the ducts after measurements
✔ Stepladder or boom lift (for accessing hard-to-reach areas—always follow local safety regulations)
Leveraging the Fluke 922’s Averaging Function
Air velocity is not uniform across a duct’s diameter and fluctuates slightly. A single reading won’t provide an accurate representation of total airflow.
To ensure precise measurements:
Take multiple readings across the duct's diameter and calculate the average as outlined in ANSI standards and "Industrial Ventilation, A Manual of Recommended Practice."
The Fluke 922’s averaging function simplifies this process, ensuring accurate readings in minimal time.
Where to Take Measurements
Measure at least three duct diameters away from:
Workstation hoods
Elbows
Branches (both upstream and downstream)
Avoid turbulent airflow near these components, as it can negatively impact measurement accuracy.
Step-by-Step Guide to Using the Fluke 922 Averaging Function
Power On & Zero the Meter
Turn on the Fluke 922 using the power button.
Press and hold "ZERO" until you hear a beep.
Connect the Pitot Tube
Attach a pitot tube long enough to span the entire duct diameter.
Select Velocity Mode
Press the "VELOCITY" button.
Insert the Pitot Tube
Position the pitot tube inside the duct—about one-quarter of the way across the diameter.
This placement ensures measurement within the highest airflow region while accounting for velocity drop near duct walls.
Activate Averaging Mode
Wait for the reading to stabilize.
Press the "MIN MAX" button three times until "MIN MAX" and "AWG" appear on the display.
Traverse the Duct Diameter
Slowly move the pitot tube across the entire duct diameter, reaching:
One wall → Opposite wall → Back to the starting point
Keep the pitot tube parallel to the duct wall throughout movement.
Hold & Record the Reading
Once back at the starting point, press the "HOLD" button.
The text "HOLD" will appear at the top of the display.
Remove the pitot tube and record the displayed average air velocity.
Reset for the Next Measurement
Press "HOLD" to release the hold function.
Press and hold "MIN MAX" until "MIN MAX" and "AWG" disappear.
Return to Step 4 for the next measurement.
⚠️ Important Note
Always activate the Fluke 922’s AWG function only when the pitot tube is properly positioned inside the duct.
Incorrect positioning (such as activating AWG while the pitot tube is outside the duct) will skew the average and produce inaccurate results.
Now that you know how to accurately measure air velocities, we’ll move on to the calibration process—fine-tuning your system’s performance to align with the fan curve and deliver precise air velocity and volume at each workstation.
📌 We recommend starting with gate (drop) calibration first. While you could begin with the main duct’s air velocity, it’s not possible to configure the system correctly without first determining air velocities at individual workstations.
Resources
🔗 What Is Not Measured Cannot Be Controlled: How Ecogate greenBOX Measures Air Velocity and Air Volume
How Air Velocity and Air Volume is Measured by Ecogate system
How to customize the Dashboard for greenBOX System Calibration
Step 1: Calibration – Air Velocity Measurement at Each Gate
The Ecogate system measures air velocity and air volume at each gate using a strategically located pressure tap, designed in compliance with AMCA standards. This pressure reading is then converted into air velocity and air volume measurements through a single calibration point in Ecogate’s proprietary software.
By calibrating each gate (drop) individually, we ensure that the measured values align with actual airflow, optimizing system performance.
Gate Air Velocity Calibration: Step by Step
1. Ensure the Ductwork is Fully Connected
Confirm that the entire duct system is fully installed and connected to its corresponding workstation.
If the workstation is not yet connected, calibration will need to be redone later, as the system’s resistance will change.
2. Run the System at a Constant Speed with Open Gates
Set the entire ventilation system to run at a constant speed with all gates fully open.
The easiest way to do this is by:
Selecting MANUAL MODE on the Power Master VFD’s front door selector.
Alternatively, set the system to BYPASS mode in the greenBOX user interface.
Both methods will open all gates and maintain a constant fan speed.
3. Measure Air Velocity at Each Gate
Use the Fluke 922’s AWG function (as described previously) to measure the air velocity at each gate (drop).
4. Adjust the Calibration Constant in greenBOX
In the greenBOX interface, locate the gate where you just measured air velocity.
Enable "Air Velocity Measurement."
Adjust the "Air Velocity Calibration Constant" until the gate's displayed value matches the Fluke 922’s measured air velocity.
Enable "Air Velocity Measurement" and adjust the "Air Velocity Calibration Constant" until the gate's measured value matches the air velocity you measured with the Fluke 922.
5. (Optional) Use a Connected Tablet for Data Entry
To improve efficiency, use a WiFi or cellular-connected tablet (e.g., an iPad) with remote access to greenBOX.
This allows for real-time data entry of measured air velocities while moving through the system.
6. Repeat for All Gates
Repeat Steps 3–5 for each installed gate in the system.
Ecogate greenBOX user interface shows Pressure, Air Velocity, and Air Volume measured at the gate (drop to the workstation).
Notes & Additional Considerations
📌 Future Software Update:
Upcoming versions of the greenBOX software will simplify this process.
You'll be able to enter the measured air velocity directly, and the software will automatically adjust the "Air Velocity Calibration Constant" when you press "Calibrate."
⚠️ Air Velocity Measurement Works Only if the Gate is Open
Air velocity cannot be measured when the gate is closed.
The pressure tap is positioned on the side of the gate facing the workstation.
If the system reads zero pressure, it confirms that the gate is closed (this is also verified by the gate’s limit switches).
Step 2: Calibration of Air Velocity & Air Volume Reading in the Main Duct
The Ecogate system offers multiple methods to measure air velocity and air volume, as not all measurement techniques are suitable for every system configuration.
Ecogate system offers three methods for measuring Air Velocity and Air Volume: External Air Velocity Sensor, Sum of Gate Air Volumes, and Fan Power, Fan Pressure, and Fan Efficiency.
Method 1: External Air Velocity Sensor
For the most accurate measurements, Ecogate recommends using an Averaging Air Velocity Sensor.
How It Works
Based on the pitot tube principle, this sensor measures velocity and static pressures at intervals across the duct diameter, ensuring accuracy by accounting for variations in air velocity.
Installed in a clean air duct, typically between the dust collector filter and fan inlet.
While the air volume at this point matches the main duct, air velocity must be recalculated for the main duct before the dust collector inlet (which is usually slightly smaller than the filter outlet or the duct between the filter system and fan).
⚠️ Installation Requirements
Install the sensor at least three to five duct diameters away from elbows (both upstream and downstream).
Avoid areas with turbulent airflow, as this can negatively impact measurement accuracy.
At Averaging Air Velocity Sensor, fill in "Duct Diameter" and "Multiplier". Enter the duct diameter where the sensor is installed. Adjust the "Multiplier" in greenBOX until the displayed Air Velocity value matches the air velocity measured with the Fluke 922.
Averaging Air Velocity Sensor Calibration: Step by Step
Run System at Constant Speed with Open Gates
Set the entire ventilation system to run at a constant speed with all gates fully open.
Do this by:
Selecting MANUAL MODE on the Power Master VFD’s front door selector.
Alternatively, use BYPASS mode in the greenBOX interface.
Measure Air Velocity at the Sensor Location
Use the Fluke 922’s AWG function to measure air velocity at the sensor location.
Take readings at least three duct diameters away from the Averaging Air Velocity Sensor and elbows (both upstream and downstream).
Input Values in greenBOX
Navigate to Modbus Devices → Averaging Air Velocity Sensor.
Enter "Duct Diameter" (the diameter where the sensor is installed).
Adjust the "Multiplier" in greenBOX until the displayed Air Velocity matches the Fluke 922’s measured velocity.
Adjust for Main Duct Differences
Since the clean duct and main duct air volume are identical, but the main duct is usually smaller, air velocity must be recalculated.
Enter the Main Duct Diameter under "02. Main Duct Air Measurement".
Main Duct Diameter should be entered at "02. Main Duct Air Measurement." Note: The diameter entered at the Averaging Air Velocity Sensor (image above) is the duct diameter where the sensor is installed.
⚠️ Upcoming Software Update
Future greenBOX software will simplify this process.
You’ll be able to enter the measured air velocity directly, and the system will automatically adjust the "Multiplier" when you press "Calibrate."
Method 2: Calculating System Air Volume by Summing Gate Air Volumes
Ecogate gates measure air volume and send this data to the greenBOX control unit. The system’s total air volume is calculated by summing individual gate air volumes.
Once the total system air volume is known, the main duct’s air velocity can be determined using the main duct diameter.
When to Use This Method
✔ Suitable for systems where all drops have Ecogate gates installed.
✔ A standard configuration in most Ecogate systems.
⚠️ Important Limitations
This method cannot be used if:
Any drops have non-Ecogate gates (e.g., manual or pneumatic gates).
There are duct openings for future equipment.
Openings exist to maintain minimum transport air velocity (e.g., oversized ducts).
No additional calibration is required. Simply input the correct main duct diameter.
Main Duct Diameter should be entered at "02. Main Duct Air Measurement."
Method 3: Determining Air Velocity/Volume Using Fan Power, Pressure, and Efficiency
This method uses:
✔ Fan Power (precisely measured by the Power Master VFD).
✔ Fan Total Static Pressure (measured by the fan pressure transmitter).
✔ Fan Efficiency (represents how effectively the fan moves air).
How It Works
This method reverses the fan power calculation formula to determine air volume. However, actual fan efficiency differs from manufacturer ratings due to real-world operating conditions:
Lab-tested efficiencies (AMCA standards) are based on ideal conditions.
In practice, installed fan efficiency can be up to 5% lower.
At “02. Main Duct Air Measurement", enter “Main Duct Diameter”, and adjust the "System Efficiency" value until the displayed air velocity matches the value measured by the Fluke 922 in the main duct.
Fan (System) Efficiency Calibration: Step by Step
Simulate Typical Operation
Set infrequently used gates to "Open Only With Sensor" (Limit this setting to a max of 1/3 of total gates).
This simulates the actual number of active gates (typically matching the number of employees using workstations).
Set the system to run at constant speed with the remaining gates fully open by activating BYPASS mode in greenBOX.
Measure Main Duct Air Velocity
Use the Fluke 922’s AWG function to measure air velocity in the main duct.
Take readings at least three duct diameters away from branches or elbows (both upstream and downstream).
Input Main Duct Diameter
Navigate to "02. Main Duct Air Measurement" in the greenBOX interface.
Enter the main duct’s precise diameter.
Calibrate System Efficiency
Adjust "System Efficiency" (which represents "Fan Efficiency as Installed") until the displayed air velocity matches the Fluke 922’s measured velocity.
Restore Gate Settings
Revert any gates temporarily set to "Open Only With Sensor" back to their original settings.
⚠️ Fan Efficiency & Accuracy
Fan efficiency decreases when operating outside the fan curve’s "Best Efficiency Point".
To improve accuracy, we recommend performing calibration near the system’s typical operating point.
📌 Upcoming Software Update
Future greenBOX software will allow you to input the measured air velocity directly.
The system will then automatically adjust the "Multiplier" upon pressing "Calibrate."
Step 3: Adjusting Fan Minimum and Maximum Speed Using Air Volume Surplus
The primary goal of calibration is to ensure your Ecogate system delivers the intended air volume to each active workstation, regardless of how many are running, while maintaining minimum transport air velocity in the ductwork.
By calibrating air velocity at both the main duct and gates, we gain a clear picture of system airflow, making this process easier.
Understanding Air Volume Surplus
Calibration involves monitoring the Air Volume Surplus, which is the difference between:
✔ Measured Air Volume (actual system airflow)
✔ Required (Design) Air Volume (expected airflow based on system design)
A small positive surplus—no matter how many gates are open—indicates proper ventilation. At the same time, the Main Duct Air Velocity must never drop below the Minimum Transport Air Velocity required for material transport.
Why a Perfectly Balanced System is Difficult to Achieve
In theory, a perfectly balanced duct system would eliminate the need to monitor individual gate air velocities—each drop would receive its design airflow when the system provides the correct total air volume.
However, real-world systems rarely achieve perfect balance due to:
Lack of Workstation Data:
Many workstations lack detailed airflow and pressure loss specifications (workstation curves), making precise calculations difficult.
Data is usually available only for large CNC machines—not all equipment.
Workflow vs. Dust Collection:
Workstation layout prioritizes workflow efficiency, not ideal dust collection.
This forces engineers to connect low-resistance machines (e.g., small saws) with high-resistance equipment (e.g., wide belt sanders), making system balancing more complex.
Duct Diameter Constraints:
Available duct diameters come in standard increments (1-inch up to 10”, 2-inch for larger sizes), sometimes requiring a slightly larger or smaller duct than ideal.
Long Duct Systems:
Systems with many branches and bends create higher pressure losses at workstations farther from the fan.
Balancing Airflow with Ecogate Systems
Manual balancing gates can help adjust individual drops but are practical only in systems with similar workstation pressure losses and low dust loads.
Instead of trying to perfectly balance every drop, Ecogate systems leverage Air Volume Surplus to optimize performance.
📌 Goal: Ensure each workstation gets at least 90% of its design airflow, even if some receive slightly more than required. This is acceptable because many workstations remain inactive, leaving extra available airflow.
❗ Perfectly balanced systems are possible but often too expensive and energy-intensive to be practical.
Configuring the Dashboard for Air Volume Surplus & Main Duct Air Velocity
To monitor Air Volume Surplus and Main Duct Air Velocity, configure your greenBOX dashboard:
From the top right “three dots” menu, configure the dashboard: select “Air Volume Surplus” from the third listbox from the top, and select “Measured Air Velocity” from the last listbox.
Setting Maximum Fan Speed
The "Maximum Fan Speed" setting is found in "01. Fan Settings" and is expressed as a percentage.
⚠️ VFD Speed Limits
The VFD’s maximum speed is set by its LIMIT parameters (for ABB drives, this is parameter 30.14 "Maximum Frequency").
Default limits:
60 Hz (North America)
50 Hz (Europe)
Special cases requiring speeds above 60 Hz are covered in a separate document.
⚠️ Why "Maximum Fan Speed" Can Exceed 100%
This is a "mapping" value, not the fan’s actual speed.
Represents the theoretical fan speed needed if all workstations ran simultaneously.
Most on-demand systems reach air volume limits before 100% workstation utilization.
For Calibration, set the system to “Auto” Mode.
How to Set Maximum Fan Speed
Step 1: Simulate Full Load
Set "System Mode" to Auto.
Activate the maximum number of workstations your system supports.
Use the "Invert Signal" function in Advanced Gate Settings.
Step 2: Adjust Based on Air Volume Surplus
Monitor "Air Volume Surplus".
If negative, gradually increase "Maximum Fan Speed" until surplus becomes positive.
If you can't achieve a positive surplus, deactivate one workstation and repeat the process.
Step 3: Fine-Tuning
If needed, increase "Maximum Fan Speed" above 100% until a positive Air Volume Surplus is reached.
Reaching 100% fan speed on the VFD tab indicates the system has hit its air volume limit.
During the calibration process, you will adjust "Maximum Fan Speed" and "Minimum Fan Speed."
Setting Minimum Fan Speed
Switch System to Auto Mode.
Activate a Single Workstation (use "Invert Signal" in Advanced Gate Settings if needed).
System Automatically Opens Additional Gates (since "Minimum Airflow" was previously configured in the greenBOX Nxt Quick Software Guide).
Monitor "Air Volume Surplus."
If negative, gradually increase "Minimum Fan Speed" until surplus is positive, ensuring proper airflow.
Monitor "Measured Air Velocity."
Must stay above the Minimum Transport Air Velocity.
If it drops too low, raise "Minimum Fan Speed."
Adjust "Minimum Airflow" if needed (some fan curves require higher minimum airflow for efficiency).
Fine-Tuning the System
Once Maximum and Minimum Fan Speeds are set, thoroughly test different workstation combinations.
✔ Continuously monitor "Air Volume Surplus".
✔ Make adjustments as needed to maintain optimal performance.
Calibrating Airflow in Duct Zones
📌 This guide does not cover duct zone calibration.
✔ A separate YouTube video and online document provides detailed instructions for calibrating airflow in duct zones.
Additional Recommended Settings
✔ Set Warning & Error Levels for Fan and Filter Pressure.
✔ Set Gate Off Delay (e.g., 60 seconds for small workstations, several minutes for large workstations).
✔ Set Fan On/Off Delay.
✔ Choose if Gates Should Be Open or Closed at System Stop (Open is recommended).
✔ Set Gate Communication Warnings & Errors (Define how many non-communicating gates will trigger warnings).
Step 4: Enjoying Your Fully Automated Ecogate System
With calibration complete, your Ecogate system is now fully automated and optimized for efficient ventilation management.
From this point forward, simply use your workstations as usual—the system will take care of the rest.
How Automation Works
✔ Activity sensors detect workstation use → Automatically starts the fan and dust collector.
✔ Unused gates close, dynamically adjusting airflow to maintain minimum transport air velocity.
✔ Air volume is continuously optimized, ensuring efficient operation at all times.
The Benefits of Ecogate
✔ Energy Savings
💰 Lower electricity consumption—the fan operates only as needed, significantly reducing energy costs.
✔ Quieter Operation
🔇 Lower fan speeds mean a quieter workspace, reducing noise levels for a more comfortable environment.
✔ Longer Filter Life
🛠️ Optimized airflow minimizes filter wear and tear, extending the lifespan of filter bags and reducing maintenance costs.
✔ Scalability & Adjustability
📈 Future-proof your system—easily add more workstations while maintaining optimal ventilation performance.
Welcome to the World of Ecogate
Where efficiency, cost savings, and a cleaner, quieter workspace come together.
Your fully calibrated system is now working at peak efficiency, ensuring the best possible performance for your facility.
🚀 Enjoy the benefits of intelligent ventilation control!
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