Understanding measurements
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Requirements
- You have active gateways in your project.
- A dashboard has already been created.
- Data sources are linked to the dashboard.
- We recommend that you review the articles below so that you are well prepared for this manual.
Quickstart guide
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What are measurement paths?
A measurement path can be composed in two ways:
- GATEWAY|SLAVE|SENSOR
- GATEWAY|SENSOR
It is the structured way in which a gateway sends information so that the Calculus platform can process it. In reality, the paths will always look something like this:
- AFGYS6GHT|modbus.rtu|vibration
- Sigfox_205871|humidity
First, we explain from which individual elements a measurement path is made up of:
- A gateway is the main device to which one or more slaves or sensors are connected. It ensures that the data are all converted to the same format, and then delivered to the Calculus platform.
- A slave is the bridge between a sensor and a gateway. You can think of it as the "input" that the sensor uses to deliver measurements to the gateway.
- A sensor is a device, module, machine or subsystem whose purpose is to detect events or changes in its environment and to send the information to other electronics, in this case the gateway.
Please note! The slave portion of the measurement path is optional, and thus will not be present in all cases. In some cases, the slave can also be a gateway. When a sensor is already connected to a gateway, and said gateway is connected to the main gateway, the slave element of the measurement path will be a secondary gateway.
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What is a calculated measurement?
A calculated measurement allows the user to perform mathematical calculations directly on the values entered in the portal. A calculated measurement uses [] brackets to use a measurement path as a parameter, and always has the following format:
[gateway|slave (=optional)|sensor]
Optionally, a particular aggregation can be specified:
[gateway|slave (=optional)|sensor#AVG]
[gateway|slave (=optional)|sensor#MAX]
Now you can use these parameters to perform mathematical calculations. For example, if you want to multiply your sensor values by 1000:
[openweather_burg_R3KR91-Q9H2O3|humidity] * 1000
It is also possible to perform calculations between two or more sensors. For example:
[openweather_burg_R3KR91-Q9H2O3|humidity] + [openweather_burg_R3KR91-Q9H2O3|clouds]
Or a combination of both:
([openweather_burg_R3KR91-Q9H2O3|humidity] + [openweather_burg_R3KR91-Q9H2O3|clouds]) * 100
For the evaluation of mathematical expressions, we use NCalc. The possibilities with calculated measurements are further explained in these articles:
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How do you make a calculated measurement?
When adding a new widget, you must first choose a data source and sensor. By doing this, you have already chosen a gateway (and an optional slave) for your measurement path. This way, your calculated measurement will have already completed the measurement path for you.
Add a square hook to the front:
[
And a square hook at the back of the path:
]
Add an optional aggregation, and the desired mathematical calculation.
Please note! Selecting a new sensor in the field above the calculated expression, a new path with that sensor is generated. This way, you do not have to type in the entire measurement path yourself.
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