The main aims of this project were to simplify the day-today work for the operator of the water treatment plant and to ensure a stable, high quality water treatment process.

The water treatment plant is fed from a mountain lake, through a 300mm pipe, at about 4 bars of pressure (natural high difference, no pumps).

The facility supplies water to roughly 500 homes in addition to a local nursing home and local businesses.

First the water runs through a course filter with automatic backwash, and then goes through two 25m3 tanks that further clean the water through an ion exchange process. The water then goes through one of two UV-lamp assemblies, before being delivered out, both directly to the nearest houses, and later via a series of pump-stations and in-ground water reservoirs (that we also have installed controllers in).

The ion exchange tanks are cleaned on user-defined intervals with a solution mixed from: salt-brine, caustic soda, and water. The solution is prepared, pumped into the tank, diluted, and then pumped back out. The solution is used and refilled a set number of times before the operator empties the storage-tank, cleans it, and then starts the process to mix a new batch automatically.

The pH is also managed by injecting sodium silicate and adjusting the amount as the waterflow goes up/down. In case of a power-cut, an automatic dosing of chlorine replaces the UV-lamps and ensures a secure water-flow even without power.

On the other stations, Prosess Automasjon AS have installed/delivered previously, they had started to implement a Modbus radio-network on the 400Mhz range (Racom radios).

The collection of information the satellite-stations around the treatment plant and showing it on screen were an important part of this project. They also implemented SMS-alarms for them all.

Prosess Automasjon AS had to replace and improve the operation from the original Mitsubishi controller without any access to the original logic. There was no documentation on how the sequence of pneumatic valves was supposed to operate apart from the accounts of the seasoned operator.

A very important part of the package that Prosess Automasjon AS strive to deliver to their customers is the possibility to have two-way SMS-communication with the controller: Receiving alarms and notifications as defined, but also having the possibility to send and SMS and request the status or values of the facility and satellite-stations.

The Norwegian Food Safety Authority have requirements to the water quality delivered, but since Prosess Automasjon AS did not change anything that would disturb the already approved water treatment, they mostly had to make sure there was no way that the caustic soda/brine mix would be delivered out to the water-users.

Where the customer previously only had LED’s to indicate the valve-positions, and the separate instruments to indicate water flow, the customer now has a big touch-display that shows all the information they need. It also gives the operator the possibility to change the timing for different parts of both the filter operation, and the “wash-cycle”-steps. The controller logs the values in historic trends, logs alarms from both the treatment plant itself and the other external stations we have connected via the radio-network. The controller both sends out SMS-alarms and responds to SMS sent from the operator where he requests information.

• Running the pneumatic vales in a correct sequence for filter/tank cleaning.
• Collecting data from both the local plant and the external station (via radio).
• Sending SMS to operator(s) both in case of alarms and in case of request.
• Logging water-flow and pressure etc for review on the controller-screen.

Prosess Automasjon AS used the ZX-controller, two SmartRail ethernet-bases with two DIM710, one DIM610, two ADC170, three DQM602 and one DAC106. Prosess Automasjon AS strive to deliver Horner controllers in as many suitable applications as they can for their price, features, and reliability.

Prosess Automasjon AS wanted a large 15″ screen to be able to present the facility overview in the best way. The SmartRail I/O system was ideal to replace the old Mitsubishi with minimal changes to wiring.

The amount of communication-port was important, as they had the SMS-modem via RS232, the Modbus radio via RS232, the external I/O, and the possibility to connect to LAN further down the road, to implement the controllers either in a SCADA or WebMI solution. They use advanced ladder on all our applications.

The SMS capability, the Modbus protocol, historic trends, and the screen were some of the Horner product features which helped to achieve the goals of the project.

After running the new Horner controller for a while and fine-tuning the sequence for cleaning (so-called regenerating) the ion exchange tanks, the operator noticed that the process is done quicker, and with less “wasting” of the mixture, so he has concluded that the older controller must have been set up with rough parameters. This means they can get more uses out of each batch of brine/caustic soda-mixture, resulting in a noticeable lower cost regarding raw materials for the mixture.