Since 1979 the Klinting Vandvaerk water company in Denmark has been a supplier of the highest quality drinking water for the western region of West Jutland. The normal population of this picturesque part of Denmark is 3000 households, but as tourism has increased in the area, and supply was extended to service the local community of Lunde and Nr.Nebel (1500 new users, giving altogether 4500 users), the water station has had to increase production drastically to keep pace with new current and future demands.
The existing water system consisted of 5 remote boreholes, a 700 m3 reservoir, green sand filter system and an outlet pipeline. The boreholes are located 1.2km from the main pumping station (in the middle of a local forest) with each borehole able to extract up to 30 m3 of water per hour, with the boreholes going down to a depth of 100 metres.
Interactive Control Is A Must
The first part of the project tackled was the reservoir, and a new 2200 m3 capacity tank was installed at the station site. The next step was to increase the number of boreholes from 5 to 11. After the mechanical elements were installed the engineers involved set about the task of updating and connecting the new system together.
Henne-Outrup EL Service was the chosen main contractor for the control system, and Leif Kirchheiner of Henne-Outrup EL Service in conjunction with Jens Kruse Madsen of Klinting Vandvaerk put the overall control system requirements together. When the overall concept was decided, specialist automation system supplier PRO/AUTOMATIC were called in to manufacture the control system panels and programme the newly chosen PLC controlled solution.
Remote Borehole Connectivity Was A Problem
The first problem to overcome was how to connect the remote boreholes pumps (up to 1.2km away) back to the water station’s new PLC control system. After looking at many network solutions specialist automation equipment supplier, Louis Poulsen proposed the latest in fieldbus technologies, CC-Link.
CC-Link can use standard cabling up to 1200 metres, but on this system the area is very flat and lightening can cause transients in communications, so a fibre-optic system with repeaters was chosen to avoid any possible network errors.
Wago Remote I/O Used On CC-Link
The master of the CC-Link network is a Mitsubishi Electric PLC which resides at the main water station. This connects via the fibre-optic cable to remote Wago CC-Link I/O modules which are connected directly to the borehole pump controllers.
CC-Link is also used to connect 10 newly installed Variable Speed Drives (VSDs) which are localized in the main pumping/filtration station back to the central control PLC.
Large Energy Saving Was A Bonus
The use of VSDs has the additional effect of saving large amounts of energy over the old direct on line (DOL) pump starting system. They do this by optimising energy usage by reducing the frequency to match instantaneous changes in pumping pressures. Using VSDs also has the advantage of extending considerably the pump’s life expectancy, and are under the real-time control of the central PLC via the CC-Link’s 10MBaud network.
Why Was CC-Link Chosen?
CC-Link was chosen as the site fieldbus standard for a few reasons. The main reason is that it was very easy to set up and install and extremely noise resistant and robust. Another reason is its unique I/O disconnect mode allowing stations to be removed from the network without affecting network performance or data loss.
PRO/AUTOMATIC says of using CC-Link “It was wonderful to use such a simple but powerful fieldbus solution. It was so easy to create the network systems and it has some very powerful and unique features such as the station removal. Another aspect we liked was that there are a growing number of automation manufacturers that now offer CC-Link connectivity and we know that by installing this network solution we are using cutting edge fieldbus technology that is supported worldwide”.
The new water control system is so flexible it can now easily accommodate the variable supply requirement. Now average water consumption ranges from 1500 to 2000 m3 per day in winter and soars up to 4-5000 m3 in the summer (due to tourism), with the CC-Link controlled system easily able to respond to real-time demands.
Download the brochure "Applications around the globe" here.