Lately I came across an interesting KNX device and I want to share my thoughts about the features and overall experience with the device. You can consider this to be the review of the device. I will probably do more KNX device reviews as I come in contact with more interesting KNX devices

So let us begin. The device I want to talk about is Gira Weather Station Standard. Order number of the device is 2150 04.

Installation

Installation of the device is pretty straight forward. Device comes with two separate parts, base of the device and the body. First you need to secure the base of the device on a vertical surface. When the base is properly mounted, you need to plug in the cable which connects base and the body of the device. After connecting the cable, you simply secure the body of the device to the base and you are done.

For proper functioning weather station needs connection with the KNX network (TP1 connection) and separate power supply (24 V AC/DC). This should not be an issue for you, since most KNX installations meet these requirements.

After physically connecting the weather station you need to program it in the ETS. There are a lot of options available in the ETS. I will cover some of them later in this post.

Mounting position

There are a couple of thing that you need to consider, before you decide where you want to position your new weather station. It is very important that you choose the mounting position carefully.

Weather station needs to be mounted on a north wall. This way all of the directional brightness sensors will function properly.

Weather station needs to be position at least 60 cm from the ground. By providing at least 60 cm clearance from the ground, the weather station will be protected from the water spray created when the water hits the ground.

Don’t mount the weather station behind some big trees or in the shades. This will influence the brightness sensors accuracy.

Don’t mount the weather station under the roof, too close to the roof. This will influence the precipitation measurement and brightness measurement.

Don’t put the weather station in the corner, too close to the walls. Corner position will influence the wind speed measurement and temperature measurement.

And please, keep the weather station accessible for maintenance. There is always a need for maintenance, sooner or later. 🙂

Features

Gira Weather Station comes with a bundle of sensors which are used to measure various physical values. The sensors are:

• Brightness sensors (3 sensors pointing east, south and west)
• Twilight sensor
• Temperature sensor
• Wind sensor
• Precipitation sensor

As you can see, the list of sensors is pretty comprehensive. When all the sensors are working, weather station can provide great overview of the outside conditions. Before you leave the house, you can check the outside conditions and decide if you need to wear a jacket instead of the sweater.

There is another, very important use case for the weather station. You can use the weather station as an automatic weather control of the shading devices.

There are probably a lot of shading devices (shutters, blinds, shades …) installed in your house. All of these device have some working parameters defined. To protect the shading devices, you need to position them correctly when the conditions are outside of the working parameters.

For example, You need to move the blinds all the way up when there is high wind outside. You can do this manually, but where is the fun in that. The other option is to program your KNX devices to do this for you. Weather station can detect that the wind speed is over a certain limit, and this information can be used by blind actuator to put the blinds in the safe position.

Another example is with brightness detection. When there is too much sun light you probably want to move the blinds down and protect the house from heating up. You can automate this function with the weather station installed in your house.

Now, when we have covered some basics, let us talk about the sensors in a bit more detail.

Brightness sensor

Brightness sensors are used for measuring intensity of the light. There are three brightness sensors installed in the weather station. If the weather station is positioned correctly, these brightness sensor should be facing east, south and west.

Brightness function provides a 2 byte objects (DPT 9.004) for outputting the current measured value of the brightness sensor.  

Since there are three sensors in the weather station, you can program them separately. For each of the sensors, you can define separate group addresses, two different limiting values and some other parameters.

In case that you don’t need separate measurements from three brightness sensors, you can combine them into one measurement function. To achieve this, you need to select Max brightness 1 to 3 option. After this all the sensor will behave as one. The measurement function will have value of the current maximum value of the brightness sensors.

Max brightness option is also useful when you cannot position the weather station correctly. You should use this option when sensor are not facing east, south and west.

Twilight sensor

Twilight sensor is basically the same as the brightness sensor. It is used to measure the intensity of the light. The only difference is that the twilight sensor is activated after brightness falls below a certain value. When the brightness value is lower than 1000 lux, twilight sensor is used for the output value.

Twilight function provides a 2 byte objects (DPT 9.004) for outputting the current measured value of the twilight sensor.

You can define group address which will be used to send the measured value, together with two different limiting values.

Temperature sensor

Temperature sensor is used to measure the surrounding temperature of the device.

Temperature function provides a 2 byte objects (DPT 9.001) for outputting the current measured value of the temperature sensor.  

You can define group address which will be used to send the measured value, together with two different limiting values.

Wind sensor

Wind sensor is used to measure the wind speed. Measured wind speed value is provided in m/s.

Temperature function provides a 2 byte objects (DPT 9.005) for outputting the current measured value of the wind sensor.  

You can define group address which will be used to send the measured value, together with two different limiting values.

Precipitation sensor

Precipitation sensor is only digital sensor in the weather station. All previously mentioned sensors are analog sensors. This means that precipitation sensor can only figure out if the rain is falling or not.

Precipitation function provides a 1 bit objects (DPT 1.001) for outputting the current measured value of the precipitation sensor.

You can define group address which will be used to send the measured value.

Limiting values

For all analog sensors you can define two limiting values. You can program each of the limiting value separately. For every limiting value you can define a threshold value. Also you can define what action needs to be taken when the defined threshold is surpassed (in both directions, increasing or decreasing).

You can configure hysteresis for every limiting value. Hysteresis represents sort of a buffer between measure value which is constantly changing and configured limiting value. It serves to prevent frequent switching forward and backward when the defined limiting value is near the measured value. In practise this means that hysteresis will prevent blinds constantly moving up and down when measured value is near the defined limiting value.

When a limit value is passed a message is sent to the KNX network. This message can be sent when measured value exceeds or undershoots the defined limiting value. Also the messages can be sent cyclically, in defined periods.

There are a couple of options available to configure the limiting values. You can program limiting values through the ETS application. Simply enter all the desired limiting values and program them to the device.

The other option is by using the teaching function which is integrated into the weather station. With the teaching function, weather station can take currently measured value and use it for a limiting value configuration.

You can configure delays for every limiting value. This means that the defined time must pass between message trigger and message sending. Have in mind that delays are applied for both message sending on value change and cyclically.

Logic gates

There are 6 logic gates available in the weather station. You can use logic gates to perform complex control logic.

For example: You can combine information about the current wind speed measurement and indication if the wind can be properly measured. In practise you can program a blind to move up when wind speed is above a certain threshold or when the wind sensor is not working. This way the blind will always be protected against high wind danger.

Blocking elements

There are 4 blocking elements available in the weather station. You can use a blocking element to pass or block a certain message in the KNX network.

You can consider a blocking element as a gate. Gate can be closed or opened. When the gate is opened the input object is forwarded to the output object unchanged. And in reverse, when the gate is closed input object is not forwarded to the output object. If during the block, the input value is changed, output value is changed as soon as the block is removed.

Final summary

Gira Weather Station Standard is great little KNX device. It provides a lot of value for the price of device.

It is very easy to start using the device. Mounting and physical assembling is very simple. It can be done in a matter of minutes.

Parameters and ETS programming needs a bit more time. There are a lot of options that need to be considered and properly defined. But when you understand all the options, there are a lot “smart” functions that you can implement with it.

You can protect your blinds against extreme weather conditions. You can adopt blinds and shades position according to weather conditions to maximise energy efficiency. It will also provide information about the outside conditions.

There are a lot more use cases for the weather station, that I didn’t mention here. Because all of this, I think that every KNX installation should have at least one of these devices installed.