HackMDTeam: Kastlunger Anna, Knibbeler Gaelle, Krzyzak Judyta
Define an IoT architecture
A nationwide gas supplier wants to monitor its gas pressure regulation stations.
- The task of these stations is to reduce the gas pressure from the distribution network to the supply network for the individual households.
- The central system has the task to receive and process data coming from the stations and to store them in a database.
- There are about 5000 gas pressure-reducing stations spread over the country.
- Only a limited amount of these stations (<400), mainly in the urban area, is connected to the company’s communication network.
- All other stations have neither power supply nor network connection.
Every station of the system should send a daily operational signal to the center in a predetermined time, together with the data collected in the preceding 24-hour interval.
- Communication should operate on an event-oriented basis – in case of any measured or detected technological parameter deviates from the specified (programmed) operational range an alarm signal should be sent to the center immediately.
- Measured technological parameters should be queried – besides the daily sign of life – upon request launched by the user from field devices, any time.
- The system should be able to maintain bi-directional direct connection with the stations. Remote programming of stations and field software updates should be made possible.
From the book IoT Fundamentals by Hanes:
1) Define and explain the High level IoT architecture for this use case.
Star of Stars:
Requirements:
- Wireless
- Low power
Vertical Specifics Application: SCADA
Scada:
Like many of the other SCADA protocols, DNP3 is based on a master/slave relationship.
- The term master in this case refers to what is typically a powerful computer located in the control center of a utility, and
- a slave is a remote device with computing resources found in a location such as a substation. DNP3 refers to slaves specifically as outstations.
Outstations monitor and collect data from devices that indicate their state, such as whether a circuit breaker is on or off, and take measurements, including voltage, current, temperature, and so on.
This data is then transmitted to the master when it is requested, or events and alarms can be sent in an asynchronous manner. The master also issues control commands, such as to start a motor or reset a circuit breaker, and logs the incoming data.
(from D. Hanes, "IoT Fundamentals")
IoT Network MGMT: MQTT (TCP) QoS1
- MQTT was specifically introduced as a protocol to monitor und control sensors and their data from a central location. It is lightweight, cost-effective and reliable.
- QoS1 means data must be acknowledged else it is resent (at least once delivery)
2) Choose a suitable access technology for the remote terminal units in the pressure regulation stations. Explain your choice.
The most suitable access technology in our opinion is LoRaWAN, because of its long range up to 40 km in rural areas paired with the low power consumption of its battery powered devices.
LoRaWAN Characteristics:
- Range:
- 2km in urban areas
- up to 40km in rural areas
- Data rate:
- between node and gateway : 0.3 - 50 kbit /s
- Adaptive data rate (ADR) set by the gateway
- Power consumption: 10 mA - 100 nA (idle)
- Maximum payload of a single message : 11 - 242 bytes
LoRaWAN - From the book IoT Fundamentals by Hanes (S.138):
For Security we would choose Activation by personalization (ABP):
- Endpoints don’t need to run a join procedure as their individual details, including DevAddr and the NwkSKey and AppSKey session keys, are preconfigured and stored in the end device.
- This same information is registered in the LoRaWAN network server.
3) Select commercial available remote terminal units for this use case.
- Our recommendation:
http://proesystech.com/wp-content/uploads/2017/03/IPS-1-Industrial-pressure-sensor-datasheet.pdf
This battery powerded gas pressure sensor has a prgrammable Microprocessor inside and can be directly connected to a LoRaWAN network.
- Other options:
