## Channel-specific settings

### Load type
Depending on the load type, the appropriate dimming method can be applied. For inductive loads, leading‑edge dimming is used; for capacitive loads, trailing‑edge dimming is applied.

The load type can be preset via the parameter *Load type*. If *Load type* is set to the value *Measured load type*, the connected load is determined once during commissioning (program download). Additionally, setting the parameter *Re-measure load type after undervoltage alarm* to *Yes* forces the re-measurement of the load type each time there is a voltage drop on the 230V side.

With the parameter *LED (combined leading/trailing edge)*, a special operating mode is available that represents a combination of leading‑edge and trailing‑edge dimming. In the section **Status of Standardization** you will find legal notices regarding this mode.

LED light sources often exhibit significant variation; even within the same type from a manufacturer, batch-related differences may occur. Whether trailing‑edge dimming, leading‑edge dimming, or the combined method is more advantageous for these light sources can sometimes only be determined by trial.

### Control Curve
The control curve determines how the light source should be driven in the leading‑edge/trailing‑edge method so that the dimming behavior of the light source is as homogeneous and linear as possible. Usually, the setting *Standard* provides good results. This is the standard in many commercially available dimming units. The *Linear* setting is only recommended in exceptional cases.

In addition to directly specifying the control curve, the Enertex KNX HV Dimmer can analyze the characteristics of the light source. From this analysis, an optimized control curve is determined via a separate algorithm (Lamp correction method). To use this function, the parameter must be set to *Measured control curve* and the light source must be calibrated.

During calibration, the complete control curve from 0% to 100% for the lamp is measured. This curve is stored in the device and remains valid until

* the channel is recalibrated,
* a factory reset is performed, or
* the dimming method for the channel is changed.

From the measurements, the device calculates the following parameters:

* Optimal dimming method for the connected light sources
* Optimal control of the brightness of the light source
* Minimal and maximal control value for the light source
* Maximum power of the connected light source

As a consequence the dimming process is homogeneous when increasing or decreasing the brightness of the lamp. For optimal dimming performance, a new calibration is therefore recommended after every light source replacement.

A calibrated control curve always depends on the light source and the load type. If either dependency changes, the calibration of the control curve must be restarted. When parameters are changed via ETS and downloaded, the calibration occurs automatically.

In order to determine the control curve, the light source must have a minimum load of 500 mW at 100% brightness. If this is not the case, only the curves *Standard* and *Linear* can be used.

### Start of Calibration of the Control Curve

For device firmware > 1.006, the calibration of the control curve is automatically initiated after a program download or restart if parameters on which it depends have changed or if the device is commissioned for the first time.
Alternatively (or if the firmware is exactly 1.006), it can be started by operating the device or via a communication object over the KNX Bus. This is especially useful after replacing the light source.

Calibration of the control curve can be initiated without ETS or further knowledge by pressing the “DISPLAY” button on the device for 10 seconds. The menu will then switch to the Commissioning page and start the calibration process for all 8 channels. This calibration process takes approximately 5 minutes. It can therefore be performed even if the device has already been commissioned. The settings parameterized in ETS, including load type (and thus the dimming method) and possibly parallel-connected channels, remain taken into account.

With the CO ***Re-measure*** for the channel, the calibration process for load type and control curve is started via bus communication. The progress of the process is reported via the CO ***Status brightness***. The process takes about 5 minutes. Multiple channels can be calibrated simultaneously.

The currently active dimming method and control curve for the channel can be queried via the COs ***Feedback active dimming method*** and ***Feedback active control curve***. A calibrated control curve is only valid for the determined dimming method for a specific light source and with the set parameters. If the load type and thus the dimming method for the light source changes, the *Standard* control curve is used until a new calibration process is started.

Once the calibration process has been completed, normal dimming can be initiated. If, for example, it is observed that the light source only switches on at 10%, this offset must be adjusted (see below).

**Note**

You can determine in various ways whether the control curve has been calibrated.

* Check for Channel A with CO 51 ***Feedback active dimming method*** and CO 51 ***Feedback active control curve***; for Channel B, use CO 101 / CO 102; for Channel C, use CO 151 / CO 152; etc.
* On the device via the “Commissioning” page, where the display shows “Calibration”. An “x” indicates that the control curve for the respective channel has been calibrated.

### Adjustment of the Minimum/Maximum control value
For fine-tuning a calibrated control curve, an adjustment of the minimum and maximum control values can be performed. The minimum and maximum control values define the brightness that the light source should exhibit when a value of 1% or 100% is commanded. The minimum adjustment should be chosen so that at a dimming value of 1% the light source barely glows. In particular, for minimal control values, LED light sources sometimes do not illuminate at 1%. Using fine adjustment, this can be corrected without re-calibrating the control curve.

For this purpose, with ***Adjustment min. control value (0%)*** and ***Adjustment max. control value (100%)***, an offset (with negative or positive signs) can be specified for the minimal and maximal dimming values. This ensures that at low dimming levels the light source always visibly lights up, and that in the higher range, a change in brightness is clearly perceptible.

The determination of these two parameters can be carried out through interactive control of the device using the buttons *Test adjustment min.* and *Test adjustment max.*.

### Interactive Fine-Tuning
Interactive fine-tuning is only fully functional once the parameterized application has been transferred to the device at least once. Otherwise, the buttons mentioned below remain grayed out.

By means of the button *Test adjustment min.*, the set *Adjustment min. control value* is directly transferred to the device. The button is grayed out if the device has not yet been commissioned. Pressing the button causes the dimmer to drive the light source at the minimal dimming level of 1% and permanently store the offset in the device. If the value for the minimum adjustment is too high, causing the lamp to light too brightly upon switching on, the value can be reduced. In this case, the button *Test adjustment min.* must be pressed to adopt the 1% drive with the adjusted offset. If the lamp does not visibly light up, the value must be increased accordingly. This can be done iteratively and never requires a complete application download; the adjustment is quickly made by pressing the *Test adjustment min.* button. The parameters are permanently stored in the device as if the application were transferred anew.

For the maximum dimming value, fine-tuning can similarly be performed with the *Test adjustment max.* button, where the device is driven to the 100% dimming level (maximum dimming value).

With interactive fine-tuning, a download of the entire application can be avoided, thus speeding up commissioning. However, during a download, the set parameters are always loaded into the device.

### Specific settings
The *Switch-on behavior* determines the *Switch-on brightness*. This parameter is also used in other functions such as **Lock functions** or **Bit scenes**. If time-based dimming is enabled, in addition to *Fixed value* and *Last value*, the option *Time-based value* is available. The time-based value is determined based on the defined time points in **Time-based dimming** and the current time.

With *Limit dimming range*, the dimming range of the channel can be restricted. When active, if a brightness lower than *Minimum Brightness* is commanded, it is instead dimmed to this minimum brightness. Similarly, with *Maximum Brightness*, if a brightness greater than the maximal brightness value is commanded, the brightness is limited accordingly. If *Limit dimming range* is set to *Restrict*, the channel can no longer be turned off using ***Relative dimming***.

The parameter *Switch-on brightness on bus voltage recovery* configures whether and to what dimming value the channels should be switched on after a device restart.

The status output of a dimming process is always provided at the end of a dimming process. Additionally, with *Behavior status output* it can be defined that

* the status is reported every X seconds during the dimming process, or
* the status is reported whenever a change greater than X percent occurs.

If *Cyclic status output* is not set to *Off*, the status outputs are sent at startup and at the chosen interval.

### Status of Standardization: Operating Mode LED Combination Leading-/Trailing-Edge
The operating mode *LED (combination leading/trailing edge)* represents a combination of leading‑edge and trailing‑edge dimming. Due to increased emissions of radio interference voltage (9 kHz - 30 MHz) in this mode, only a lamp load of up to 100 W is permitted. Furthermore, the limit values for the maximum permissible harmonic currents (100 Hz - 2 kHz) for dimmers are defined in the standard EN IEC 61000-3-2. This standard is not clear regarding the operation of dimmers in this mode. Although the harmonic distortion caused by the combined mode is lower than what occurs with solely leading‑edge or solely trailing‑edge dimming, this combined mode is not explicitly mentioned in the standard; therefore, in case of doubt (within the EU), this mode should not be used without additional filtering measures in the low-voltage network.
