In this guide you will learn how to set up, run and read a Step Commissioning test on an ECL controller in Leanheat® Monitor. For an explanation of what a step response test is and what it is used for, see Introduction to Step Commissioning.
Before you start
You need all of the following:
A supported device. An ECL device connected through connection type "ECL". The Step Commissioning tab is not available for other device types or other connection types.
A user role with commissioning rights. Basic users and Read-only users cannot open the tab.
A device that is online. The test reads the controller before it starts, and it fails if the device does not answer.
Write down the current settings of the circuit before you start. Note the reference mode, and note the heat curve minimum temperature and maximum temperature. You need these values if you cancel the test before it finishes, see Cancelling a running test below.
Where to find it
Open a device and select the Step Commissioning tab. The tab lists every test on this device, with its Description, Status, Execution time and Source.
Setting up a test
Select "New Commissioning". The "Setup Commissioning" window opens.
Select the "Circuit number". The list shows only the circuits that exist on this device. When you select a circuit, Leanheat Monitor reads the controller and shows the "Current coefficients", Xp and Tn, next to the field. The message "Error loading coefficients" means the device does not answer. Do not schedule the test in that case, check the connection of the device first.
Select the "Source": "Heating", "DHW" or "Ventilation". The source decides which controller values the test changes.
Enter a "Description". A description is required. You see it in the list of tests and in the result.
Enter the "Minimum Temperature (°C)". This is the lowest temperature the test is allowed to use. If the setpoint of the device is below this value, the test raises it to this minimum, so that there is enough action to observe.
Enter the "Step Delta (°C)". This is the size of the temperature step. The test raises the setpoint by this value in step 2, and lowers it by the same value in step 3. The smallest step you can enter is 1 °C.
Enter the "Step Time (minutes)". This is the duration of one step, and all three steps last this long. The allowed range is 1 to 120 minutes.
Set the "Start date" and the "Time", or turn on "Execute now" to start the test immediately. The date field and the time field are disabled while "Execute now" is on.
Select "Apply". The test appears in the list with the status Scheduled.
How to choose Step Delta and Step Time
Choose a Step Delta that is large enough to see above the normal variation of the measurement, and still small enough to keep the building comfortable.
Choose a Step Time that is long enough for the temperature to settle after the step. A step that is too short cuts off the response and hides the settling behaviour. A typical value for a ventilation circuit is 30 minutes.
The total duration of a test is three times the Step Time. A Step Time of 30 minutes gives a test of 90 minutes. The longest possible test is 6 hours.
What happens during the test
The test runs on its own, and you do not need to stay on the page. It has four phases:
Step 1, baseline, at the start: the current setpoint, or the Minimum Temperature if the current setpoint is lower.
Step 2, raise, after one Step Time: the baseline plus the Step Delta.
Step 3, return, after two Step Times: back to the baseline.
Restore, after three Step Times: the original settings of the controller. The test is then Completed.
To hold the setpoint steady, the test switches the circuit to constant comfort reference mode for the duration of the test. For heating circuits and ventilation circuits it also flattens the heat curve. The test writes the reference mode and the heat curve back when it finishes.
The test records the measured temperature and the reference every 10 seconds. These readings are normal measurements, so you also find them in the graph of the device.
Two effects are visible while the test runs:
The device settings are locked. The settings panel is read-only and the settings icon shows a warning badge. The tooltip reads "Settings are currently unavailable due to running step response test. Please wait a few minutes before accessing settings." The settings unlock when the test finishes.
The building temperature changes. The test raises the flow temperature of the circuit by the Step Delta for one third of the test. Occupants can notice this, so run the test at a time that suits the building.
Test statuses
Scheduled: the test is planned and has not started.
Running: the test is executing on the device.
Completed: the test finished and the settings of the controller are restored. A result chart is available.
Cancelled: a user stopped the test.
Error: the test could not run, see If a test ends with Error below.
Actions on a test
Open the three dots menu on a row. The available actions depend on the status:
Scheduled: Edit test, Show test configuration, Cancel test, Delete test.
Running: Show test configuration, Cancel test.
Completed: Show test configuration, Show test result, Rerun test, Delete test.
Cancelled: Show test configuration, Rerun test, Delete test.
Error: Show test configuration, Rerun test, Delete test.
You can edit a test only while it is Scheduled. The configuration is locked once the test starts. "Rerun test" runs the same configuration again at a new start date. "Show test result" is available only for a completed test, because a cancelled test and a failed test have no chart.
Cancelling a running test
Cancel a running test only when you must. Leanheat Monitor does not restore the controller settings when you cancel a test that is already running.
After a cancelled test the circuit stays in constant comfort reference mode. For a heating circuit or a ventilation circuit the heat curve stays flat at the test setpoint. The circuit stays in this state until you change it. Restore these settings by hand after you cancel a running test:
Set the reference mode of the circuit back to its original value.
Set the heat curve minimum temperature and maximum temperature back to their original values.
This is the reason to note the original values before you start the test.
A test that is still Scheduled has not written anything to the device. You can cancel or delete it with no effect on the controller.
Reading the result
Select "Show test result" on a completed test. The "Commissioning results" window opens.
The window lists the settings of the run above the chart: circuit, source, description, start date, minimum temperature, step delta, step time, Xp, Tn, and the measurement interval of 10 seconds. The values of Xp and Tn are the values that were active on the controller during this test.
The chart shows two lines. The dashed line is the reference, the setpoint that the test asked for, and it shows the three steps. The solid line is the measured temperature, the response of the circuit. You can drag across a part of the chart to zoom into it.
Judge the tuning from the shape of the measured line after each step:
The temperature reaches the new setpoint and stays there: the tuning is good.
The temperature overshoots the setpoint and then oscillates around it: the control action is too strong. Increase Xp, or increase Tn, or do both.
The temperature rises slowly and does not reach the setpoint within the step: the control action is too weak. Decrease Xp, or decrease Tn, or do both.
The temperature does not move at all: the circuit did not follow the test. Check the influence warning described below, and check the state of the valve.
Change one parameter at a time, run the test again after each change, and compare the two charts. The tuning values are changed in the device settings.
Exporting the result as a PDF
Select "Export graph" in the result window. Leanheat Monitor creates the PDF in your browser. It contains a Leanheat® Monitor header, the settings of the run, and the chart. The file name has the form step_response_test_report-<source>-circuit-<number>-<date>.
Influence warning
The tab shows this warning when other functions also control the setpoints of the device:
The warning appears when at least one of the following is true:
The device is part of a shared time schedule.
Smart Weather Compensation is set up for the device.
The device is used in a data relay, a curve relay, a weather relay, or a critical point relay.
All of these change the setpoints of the device. They can work against the test and distort the result. The warning does not stop the test. Disable the other function for the duration of the test, or accept that the result can be distorted.
If a test ends with Error
A test gets the status Error when Leanheat Monitor cannot read the controller at the start time. The most common reason is a device that is offline.
A failed test writes nothing to the controller, so the settings of the device are unchanged. Check that the device is online, then use "Rerun test" to schedule the same configuration again.