Electricity + Control February 2019

SENSORS, SWITCHES + TRANSDUCERS

Flexible automation system for mini pilot hydropower plant S ensor specialist ifm electronic (SA) was asked to provide an automation and con- trol solution, including instrumentation, for Programmable Logic Controller The AC1423 DataLine SmartPLC ( Figure 3 ) was selected for plant control. The AC1423 is freely programmable using CodeSys V3.5 and offers full access to all interfaces of the PLC as well as SCA- DA development. By Vishal Bachoo, ifm electronic (SA)

The client wanted a sys- tem solution with the least number of possible failure points. Take Note!

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a mini pilot hydropower plant ( Figure 1 ). The client specifically requested a system solution with the least number of possible failure points and one that would offer comprehensive diagnostic abilities.The plant process was to be controlled via a PLC (Pro- grammable Logic Controller) including a SCADA system with data logging for management. In outline, hydropower plants collect the energy from falling water to generate electricity. A turbine converts the kinetic energy of falling water into me- chanical energy and then a generator converts the mechanical energy (via the turbine) into electricity.

Two Ethernet ports act as fieldbus/slave inter- face (Profinet, Ethernet/IP, EtherCAT) and enable high-performance communication to other PLC systems. Different communication protocols can be used in parallel via two further Ethernet ports, for example, EtherCAT master, Ethernet/IP scan- ner, Modbus TCP/IP master and slave, TCP/IP, UDP/IP or OPC/UA server. IO-Link was selected for point-to-point com- munication from the sensors and actuators to the higher end automation system. This approach will ensure that the plant is Industry 4.0 ready and offer the extended diagnostics as required.With IO-Link specified instrumentation and Ethernet IP power

meters, the system is designed to provide full control and diagnostic information for the operator.

Figure 3: The AC1423 SmartPLC was selected for plant control.

Field IO modules Decentralised AL1122 ( Figure 4 ) IO-Link master modules (Ethernet/IP) are used as gateways be- tween intelligent IO-Link sensors and the fieldbus. These IO-Link masters for field applications provide for the connection of up to eight IO-Link devices, including sensors, valves or binary input/ output modules. The modules provide reliable transmission of process parameters and diagnostic data to the controller. Excellent electromagnetic stability, a wide temperature range, a high protection rating and robust housing qualify the device for use in harsh industrial environments. ifm’s IO-Link con- nection technology guarantees reliable, perma- nently ingress-resistant M12 connections on the connection cables.

Figure 1: Hydropower plant.

The automation system solution The plant is divided into five operational zones ( Figure 2 ) and the inputs and outputs (IO) count in

each zone was consid- ered for the PLC and IO module selection, with power consump- tion also taken into account.

Figure 2: Network layout across the five operation- al zones.

24 Electricity + Control

FEBRUARY 2019