Designed-in diagnostics keeps machines productive.

Analog pressure sensor offers component-level diagnostics through a display that shows all relevant operational data.

Valve terminal with field bus and integrated I/O provides point-level diagnostics.

Data flow represents data access of all pneumatic components.

A simple block diagram and sensor selection screen shows pressure and flow in main line.

As the demand for technical advances and cost reduction in automation continues to increase, companies look for new methods to improve overall equipment efficiency. To keep a machine running for millions of cycles, every component in its pneumatic system must continue to operate properly. Monitoring key system status indicators for the life of a machine — together with predictive information — can reduce unscheduled and lengthy downtime by eliminating time-consuming error identifi-cation and component testing and replacement. Currently, the available data describing machine status are still insufficient, so a new method must be developed to provide additional operating data from all system components.

To meet this demand, Festo has begun to develop new tools for the next generation of diagnostic programs using software, hardware, and a variety of services. Eventually, this will provide most companies with the ability to measure overall equipment efficiency, reduce service costs, and improve the effectiveness of maintenance support teams and preventive maintenance programs.

A new approach to system diagnostics
The introduction of smart sensors with analog output provided many characteristics common to high-end sensing devices. Designed for operation using menu prompting or a type of double teach-in method, these sensors offered component-level diagnostics by incorporating a display showing all relevant operational data. This was made possible by implementing microprocessor control and programmability.

Other smart devices, such as valve terminals with integrated I/O provide point-level diagnostics. These allow users to identify which sensor channel in a terminal may be causing an error — such as signals sent from pressure, temperature, flow, or level sensors. They also provide module and channel-specific diagnostics, designed to find low voltage, short-circuit detection of sensors, open-load detection of missing valve coils, and other malfunctioning outputs and valve functions.

What's coming up
Despite some highly specialized solutions for certain industry applications, no real system diagnostics approach using standard pneumatic products existed until now. Many suppliers have offered a variety of different diagnostic sensors and other devices that can generally be classified as a sophisticated method of data collection and processing. But with a complete systems approach, industry will have its first diagnostic solution that includes all components in a pneumatic system.

This comprehensive system offers a means of increasing productivity by identifying potential component or system-wide faults. Unlike traditional component-based diagnostics, this systems approach incorporates the entire pneumatic process — from air supply to actuators — by integrating valves, drives, service units, and sensors into one system. Regardless of the degree of automation, pneumatic components and systems can be monitored and measured to meet desired parameters.

The Festo pneumatic system diagnostics program combines multiple levels of diagnosis with an ability to access system data and adjust overall system performance quickly and easily. By using flexible system architecture, users can customize diagnostic functions and access cross-sectional system data that will affect speed, output, and overall performance for the lifetime of the machine.

The software tool being developed analyzes the incoming data, compares it to predetermined parameters, and suggests improvements to performance of not just the individual device, but the entire system as well. Analog output signals from pressure and flow sensors can be used to analyze pressure and air flow values, providing current system status. The software can also be used to monitor pneumatic tubing, service (F-R-L) units, and vacuum components, and provide information on leakage, flow restrictions, and pressure changes.

This program arms machine builders and automation specialists with machine-level tools for on-site evaluation and integration of diagnostic information into standard control environments. Freed of the traditional constraints of common pneumatic components, companies will be able to focus their energy on improving production and quality.

Hardware and software solutions
A flexible tool kit allows adaptation for a broad range of industrial applications, with a focus on system monitoring and diagnosis to enhance overall equipment efficiency. Festo's flexible hardware and software platform uses smart valve terminals and similar components as data collection and preprocessing units for monitoring switching cycles, flow rate, pressure, operating status, and more. In conjunction with software, users have new diagnostic functionality that is continually enhanced to meet changing requirements.

The system diagnostics software can be easily configured for a different number of components and functions, and requires using only basic sensors (end-position switches) and valve control signals. Analog signals can be specified for the main supply line as well as for actuator lines if additional diagnostic functions are needed. Users simply select a monitoring strategy and measurable system parameters, and the software will determine the difference between the programmed tolerances and actual operating status, providing a warning or alarm message — or both — when these settings are exceeded.

Standard control compatibility
Adjustments can be made manually or automatically online. Pneumatic system status data is accessible through standard field-bus technology. The diagnostics tool allows on-site evaluation by plant personnel, as well as integration of diagnostic information into standard control environments. Adjustments and replacements can be made quickly and easily due to improved identification of responsible subsystems.

Designed for maximum flexibility, the proposed software offers customized diagnostic functions to improve overall system performance. Performance results can be viewed on a PC using common visualization tools such as RS View (or WinCC) or through a diagnostic graphical user interface. Current system data can be recorded, printed, and exported for use in standard report tools.