Developing an Automated Water Management in a Coolant Facility with LabVIEW and FieldPoint

Author(s):
Susanne Spiessberger - Grandalytics
Guenter Randolf - Grandalytics

Industry:
Industrial Controls/ Devices/ Systems

Products:
Compact FieldPoint, FieldPoint, LabVIEW Datalogging and Supervisory Control Module, LabVIEW

The Challenge:
Automating the monitoring and controlling of two coolant circulation systems for engine test benches, with all operations – surveillance of the water level and water supply, switching the softener container, and initiating regeneration – registered and controlled by the new system.

The Solution:
Developing an easy-to-use, expandable setup using NI FieldPoint and LabVIEW Real-Time, which ensures stability and enhances reliability and compactness because of the capability to directly integrate sensors without signal conditioning.

Installing a New Water System for High Use
Because of the high use of its existing coolant facility, the Austrian Magna subsidiary company Engineering Center Steyr GmbH & Co KG contracted our company to install a new water management system. In test benches for combustion engines, water cooling is essential for operating the heat exchanger of the main cooling system and the eddy current brake. Closed or semiclosed cooling cycles reduce water consumption and increase economic efficiency. However, in semiclosed systems, additives and particles evaporate more slowly than water, causing the water’s impurity and electrical conductivity to increase. At certain levels of conductivity, some water has to be replaced by conditioned water (desalination). Cooling systems, such as micro controller-equipped units for softening or conductivity control, are widely spread. However, these stand-alone solutions will not act together sufficiently. Therefore, we used NI tools to design an innovative, overall control setup that meets the given demands.

High Reliability and Expandability; Short Code Development Time
We selected FieldPoint 2000 to ensure high reliability and expandability of the controlling unit as well as short code development time. Each bank consists of one dual-channel terminal base with 4xPT100, 4x4-20mA, and 2x0-10V input channels and one 16x digital output module. The user can save data locally on the control unit, providing an easy data upload to a local server. A user interface runs on the local server to provide information about the current and historical status and can be used to request an upload or download of data.

The developed control unit performs several tasks including monitoring of water level, temperature, pump pressure, conductivity, the supply of softened water, water hardness control, and regeneration of the softening unit. No further nod is required. The same master unit controls both of the independent cooling cycles, and in case of emergency, each water treatment unit can supply both cooling systems. All relevant measurement data are logged automatically, which enables the deduction of important trends like the connection between water consumption and temperature.

Each cooling unit is equipped with sensors for:
· Conductivity
· Water consumption
· Water level (ultrasonic)
· Temperature
· Pressure

We can embed additional sensors (hardness, pH-value) easily.

To guarantee high-quality refill water, each facility uses a twin tank alternating softening system. If one tank is rundown after draining the specified water volume, it is switched to a regeneration status while the other tank continues to supply water. Since the required amount of refill water varies with cooling power, and temperature, the capacity of the softening unit must consider even peak requirements. By using a new innovative controlling system, the unit can be scaled down to cover the average need. Unlike many of the conventional controlling units, the developed system enables subsequent regeneration only if the brine is ready. If a sufficient amount of time is not provided for regeneration of the brine, hard water will enter the system causing fatal consequences like calcification of the pipes and hot surfaces on the breaks and heat exchangers. Settings for either one or two brine barrels provide the fastest regeneration without any risk of overrunning the system. The required hardness of feed-water can be achieved through calculating the overall water hardness and operating a bypass valve accordingly.

Watchdog Functionality Ensures Quality
A watchdog function periodically checks the regeneration process and valves. If a measurement channel provides out-of-range data, a warning or error condition arises. In this case, a snapshot of all parameters is stored and an alarm (flashing light and horn) is activated. The optical/acoustical signal is latched until it is acknowledged. To prevent loss of information due to a power failure, important data like regeneration phase or valve positions are periodically stored in a temporary file on the flash RAM of the controller. After the device reboots, the temporary file supplies all the information to the controller, which continues operating at the point of interruption. The internal error is cleared after each software cycle.

The online user interface enables monitoring of data, which is provided by the controller through DataSocket. In online mode, the interface shows the actual status of all channels, error messages, regeneration information, and valve status, and in offline mode, it displays charts and trends of historical data stored in the database. By performing a request-for-data, the latest information is uploaded from the FieldPoint 2000 Flash RAM to the database. Through the LabVIEW HTTP server and CGI, we can operate both interfaces by a Web browser at any workstation.

Several calibration parameters and limits are stored in an initialization file. Changes to settings are made at the local server, and thereafter, the user can request a download of the new file to the controller. The controller sends a request-for-file with a local and remote file name to the server, which transfers the file through FTP, followed by an OK tag. The controller checks the file for validation and replaces the old initialization file, which allows a safe update without interrupting the controller. The upload of measurement data is done similarly. For convenience, a new file is created each month, and data compression and automatic size check prevent an out-of-memory on the controller.

A Successful, Innovative Overall Solution
This new network-based water management system works successfully and provides an innovative overall solution to replacing the previous noninteracting controllers. The reliability of the FieldPoint controller together with software safety features prevents system crashes that can cause a considerable loss of production time. Fully automated measurements make the operation much more convenient and time and cost-effective by lowering personnel costs and down time. The new system supports higher water capacity at a good quality, reducing the number of shutdowns and fatal consequences caused by high water hardness. It also enhances flexibility as each water treatment unit can supply both cooling systems by cross switching. Water is saved because the new system prevents the complete draining of the cooling basins. Furthermore, the modular setup of the system allows future, low-cost expansion and adaptation with regard to other facilities. Considering all these factors, with this new system built on NI tools, our customer saves up to 10 percent of total costs.

For more information, contact:
Guenter Randolf
GRandalytics
Phone: +43 761290032701
Fax: +43 761290032703
E-Mail: info@grandalytics.com

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