Exercise 1
Data acquisition and transmission module for flowmeters
The Hydraulic company has flowmeters installed in different facilities such as extraction wells, work centers and hotels. These facilities are far from the central control station. The flowmeters installed in these facilities have a 4-20 mA output. As these facilities are so distant from the control room, it is not possible to connect them with cables to the PLC and therefore to the SCADA. To know the behavior of these variables, it is necessary to move an operator to each of the locations. This situation leads to incurring unnecessary expenses and losing immediacy in receiving the data and making decisions regarding them. Therefore, a module capable of reading and wirelessly transmitting the readings of the flowmeters is needed.
The theme of this project is justified since it is known that there is a need for companies that control water resources in the country to manage data remotely. Associations such as Aguas Varadero have approached our university and have expressed their problems and their interest in collaborating once the reliability of the product has been demonstrated.
Additionally, the importance of data collection for decision-making and the proper management of resources has been evidenced. It should be noted that the operation without human intervention is capable of working more efficiently and in cases like this, where it is necessary to transfer personnel with their consequent logistical assurance to obtain the data, valuable resources would be saved.
The prototype intends to adopt an architecture that not only allows it to be integrated into hydraulic systems, but its operation can be extended to other areas of data collection and transmission.
Proposal for collecting and sending data from the flowmeters to the PLC.
It is intended to develop two variants of the prototype, one that works with power from the electrical network and another that works with rechargeable batteries and solar panels.
Variant 1: With power supply
It is intended to take the reading of a flowmeter that provides 4-20mA output using low cost devices. For this, it is necessary to convert the signal to voltage values that the microcontroller is capable of processing, which requires the use of a current-to-voltage converter. The data is processed by the ESP32 that allows the sending of information both by Wi-Fi and by Bluetooth, a GSM module is included to send the data using mobile telephony to the central PLC.

1 proposed architecture

Controller: ESP32
The ESP32 development board is a 32-bit SoC (System on Chip) that includes Wi-Fi and Bluetooth communication and has, among other features, 4Mb of flash memory.

Value: 4-7 USD

Communication: GSM-GPRS module
Mobile phone network module that works in the frequencies of 900MHz or 2100 MHz (2G and 3G in Cuba) and is powered by 5V. Or be quad band which includes the 900MHz frequency.

Value: 6-10 USD.

4-20mA to 0-3.3V converter
Signal Converter and Voltage Transmitter Module, 0 -20mA/4 -20mA to 0-3.3V/0 -5V/0 -10V, Voltage Current Module.

Value: 1-2 USD

Power boost module
Converter from 3.3V-35V to 5V, 6V, 9V, 12V, 24V, XL6019.

Value: 1-2 USD

Power supply
Power supply with 100 - 240V input and 5V output with 5A.
Value: 8-10 USD

Economic analysis:
Table 1
Componentes Value (USD)
ESP32 4 a 7
GSM-GPRS module 8 a 10
converter 1 a 3
Power supply 8 a 10
Power boost module 1 a 2
Micro-USB cable 1
Arduino power cable 1

Total 24 a 34

Variant 2: With Battery and solar panel

Figure 2 Proposed architecture for power supply by solar panel and battery
If you want the system to work autonomously, it is possible to place rechargeable batteries and solar panels that provide it with power. In addition to the components described in variant 1, the modules that are framed in Figure 2 should be incorporated and the power supply can be dispensed with.

Table 2 Economic analysis of the variant

Componentes
Value (USD)
Solar panel 3.50
Elevador de voltaje 1 a 2
charger module 1.10
lithium battery 6
Cable micro USB 1
Cable alimentación Arduino 1
ESP32 4 a 7
GSM-GPRS module 8 a 10
Converter (3) 3 a 9
Power boost module 1 a 2

Total 29 a 41

List of components
Solar panel 5V 1.5W
Battery charger module: includes the lithium battery socket, power boost board, and the TP4056 battery charger.

 

Rechargeable batteries lICR18650 3.7V 9800 mAh
Value: 6 usd