Pressure measurement Step-by-Step digitaliSation


1. Specify data recording points/measuring points for a POC (proof of concept)


2. Define a suitable pressure transmitter based on requirements such as accuracy, compatibility of media (the level sensor series 36XW for ground water levels, for example)


3. Select transmission technology LoRaWAN or mobile communications (Remote data transmission unit ADT1- Tube for LoRaWAN or ARC1-Tube for mobile communications, for example). Check which network coverage is available at the measuring point for the selected technology. The measuring points selected should be as close as possible to the person responsible for the system so the discrepancy can be found and remedied in the event of a fault on site. Verification of the measured values recorded should also be performed during operation at the measuring location.


4. Operate measuring points with the help of a graphical representation in a cloud for a few weeks and monitor closely (using KOLIBRI Cloud, for example)


5. Expand the measuring system (POC) with additional, possibly technically critical measuring points and close monitoring of any discrepancies


According to this expanded concept, the


entire system is to be fundamentally evaluated and assessed with regard to whether the results correspond to expectations. Up until this stage, the IoT measuring


system from KELLER was able to be used with little investment. It must now be assessed whether the system is to be kept as it is and, as such, the digitalisation project concluded, or whether a deeper integration of the system into the company’s software is desired.


6. Automatic data synchronisation between the measuring system and the company’s own cloud. Please note, the service providers of the company’s own software often do not know the process of generating IoT measurement data. KELLER’s many years of experience helps here to establish clear and concrete functional requirements for the measurement data it records in an external system.


7. Complete vertical integration Pressure sensor or transmitter, remote data transmission unit, KOLIBRI Cloud


open interfaceS for all componentS of the entire meaSurement chain


Digitalisation of the pressure sensor signal The pressure sensor signals are processed and digitalised using an electronic circuit. This means they are converted into a number (pressure) that can be retrieved via an interface. Other useful information can also be taken from the pressure sensor in addition to pressure and temperature. In many cases, too little attention is paid during


the initial process considerations to the importance of an accurate, stable and reliable sensor. The sensor that records the data is one of the most important parts of the system because decisions are made and actions taken based on this sensor data:


Switch off the machine Fill up the tank


Ground water level too low = signals no supply of drinking water!


Ground water level too high = signals flood!


Consequently, the sensor, which is at the start of


the entire measuring chain, has the greatest influence on the quality of the data and must be selected or designed according to the requirements of the measuring system. KELLER offers specifically developed and tested


pressure sensors for the respective application and requirement. For the use of pressure transmitters with the user’s own hardware to transmit the measured data, KELLER provides the communication protocols for the RS485 or I2C interfaces. For applications that are meant to use a pressure sensor without a standardised output signal, the calibration data is supplied to the sensor.


Remote transmission Another important part of digitalisation is transmission of the recorded data. Often sensors are located in places that are far away from the central collection and evaluation point, or the sensors cannot be connected to a local communication network. The Internet of Things (IoT) is a global network


that enables the exchange of data via the Internet. This means that sensor data, for example, that has been generated at different locations around the world can be amalgamated in one system (cloud). A prerequisite for this function is that the device, the machine or the sensor has access to the Internet. For the measuring solution from KELLER, we use autonomous, battery-operated IoT devices that transmit data via various radio interfaces. One advantage is that these devices can be


installed with little effort as there is no need for cabling and the measuring devices do not have to be incorporated into a company communication network. So that the devices and their batteries have a service life of several years, standardised radio technologies (LoRaWAN as well as mobile communications 2G, 3G, 4G, NB-IoT, LTE-M) with low energy consumption and a long transmission range of 15 km and over are used alongside an


Continued on page 38...


Instrumentation Monthly January 2021


37


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74