Condition Monitoring on a drillship - HYDAC International GmbH

Pict. 1: On such drillships condition monitoring is particularly important

HYDAC is one of the leading corporations in the field of fluid technology and hydraulics, offering a comprehensive product portfolio of hydraulic components. These products are used in many areas such as the automotive industry, machine tools, aviation, steelworks, navigation and construction machinery. Of crucial importance for the faultless function of the hydraulics is the quality of the hydraulic oil. HYDAC's appropriate sensors capture the essential measured variables of the machines or plant hydraulics in operation. The core piece is the central data recording and evaluation through the CM-Expert condition monitoring tool. This keeps the plant operator informed about the exact condition of the hydraulics at any time, guarantees a reliable operation, and allows needs-oriented and planable maintenance. For the redevelopment of the condition monitoring tool HYDAC required an appropriate development tool. Among the search criteria were current technology. integration into the .NET framework, free expandability for special functions, and simple interaction with Visual Studio.

Practical application drillship

The concrete example of a drillship particularly exemplifies the use of the condition monitoring system. Through a special compensation system coupled with dynamic positioning the Stena Drilling drillship can provide its full drilling capacity of up to 3,000m depth in seas of up to 7.60m. The monitored hydraulic plant feeds five huge hydraulic cylinders that control the lifting and lowering of the drill stem. In addition these cylinders define the pressure put on the drill head. Loads of up to 1,000 tons can be lifted and lowered through these cylinders. The hydraulic plant has an oil volume of 90,000 litres with a maximum flow rate of 24,000 litres per minute. The offshore operation with its extreme environmental conditions is particularly demanding on the hydraulics and makes the supply of spare parts expensive. A hydraulics breakdown leading to an operational standstill would go along with high cost. Therefore, the crucial parameters of the hydraulic plant are permanently monitored by the condition monitoring tool. Through an self-contained system that is independent from the hydraulics control the different criteria are gathered by sensors. The measured variables from the more than 80 sensors are passed through a control to the condition monitoring system where they are recorded and monitored. The permanent monitoring and documentation of the hydraulics data automatically informs the user about maintenance-relevant state variables, and alarms him should safety-relevant values be exeeded or underrun. This allows avoiding cost-intensive breakdowns and consequential losses, and improving machine availability. Maintenance and servicing activities can be optimized, and components be used to the full potential of their operating life.

Software for the condition monitoring

The flexible and modular design of the CM-Expert software allows its use not only in the above mentioned hydraulics applications. As another example the monitoring of clean rooms with air particle measurement is conceivable, made possible by the flexibility of both the software and the control. The open and manufacturer-independent system allows the connection with different sensor types. Even other manufacturers' sensors can be connected and interpreted which further expands the possibilities of the application. Due to its self-contained design, independent from the already existing control solution, the system can be added to any existing plant without problems. In the condition monitoring system the measured variables are recorded and filed. For every measured variable monitoring limits can be defined, and a message or alarm triggered if they are exceeded or underrun. These monitoring limits can with the appropriate user rights at any time be amended through a context menu with the appropriate sensor control. In addition, a graphic line chart display of the sensor value can be accessed. This provides the user with a direct view of the change of the measured variable over the time. The software was optimized so that the user can freely define the values to be displayed on a so-called favorites page. This goes as far as any number of values being displayed in different charts, and the display parameters being freely set, and allows the user to display the most important process parameters centrally on one screen. He can also save and print out the display for protocol and documentation purposes. An export function allows selection and storage of the recorded data, e.g. for further external evaluation in Excel.

Pict. 2: The condition monitoring software is based on the VisiWinNET process visualization system

Process visualization as the basis

The INOSOFT VisiWinNET process visualization system is the basis for the CM-Expert condition monitoring system. VisiWinNET Professional is the appropriate development tool for HYDAC, containing the required functions, and in addition providing the possibility to simply integrate own functions. This enabled the HYDEC specialists to build on the broad functional range of the process visualization system, and for example realize the simple link with the control through an OPC server. A further standard function is the alarm and messaging system for displaying and recording the alarms. The upcoming alarms and messages are displayed to the user in a clearly arranged way. In addition to acknowledging the alarms the user can also lodge a note on the alarm. The evaluation of the historic alarms and notes allows the plant operator to draw conclusions for process optimization. Recording and filing of the data is done in the VisiWinNET archive system. This provides a simple facility for a graphic display of the recorded data. This way, the value pattern of every recorded sensor can be displayed as a trend chart. As an internationally active corporation with worldwide usage of the software adapting the language to the appropriate national language of the customer through the integrated online localization is an important function for HYDAC. CMExpert also offers configuration and setting facilities to the end user. These are linked to appropriate user rights so that for example only authorized persons can adapt the limit values for the monitoring. The VisiWinNET user administration allows simple user configuration, and provides prepared templates that were adapted by HYDAC for their application.

Pict. 3: The integration of VisiWinNET Professional into Visual Studio allowed HYDAC the realization of special requirements with own controls

Client-specific enhancement

The integration of VisiWinNET Professional into Visual Studio allowed HYDAC the realization of special requirements for their condition monitoring software with self-created controls . An example is the analog sensor control, one of the main operating elements for the user. It connects the most important data of a sensor centrally in a control. This way, as an example, the measured variable is displayed as text as well as graphically through a bar graph that changes its color in dependence of a limit value violation. To provide the user with a quick overview the monitoring limits are shown directly in the control. As a central operating element the sensor control not only shows the measured value but also allows the access of further functions through a context menu. This way, the user with the appropriate user right can for example directly enter a dialog to change the limit values or access a graphic display of the measured value progress through a trend chart. A smooth transition between online and historic data makes it easy for the user to display past data. This can be controlled by entering a certain timespan or intuitively through a scroll bar. "With the system we have made the right choice for the redevelopment of our CM-Expert. It provides many standard functions, and allows us the free adaption to our field of application. VisiWinNET has the flexible and open structure that we wished for“, sums up Robertus Koppies, Head of the Condition-Monitoring department with HYDAC.

Author: André Weber, Digitec Vertriebs GmbH

Manufacturer of the Condition Monitoring system: www.hydac.com