**6. Integration with ICAS**

The next step was to integrate the laboratory nondestructive AE test system into field applications for performance monitoring of a high-power microwave radar tube [8]. Currently, the Navy is using ICAS version 4.11 (IDAX Inc. Norfolk, VA) for the performance monitoring of mechanical systems on ships. The Integrated Condition Assessment System (ICAS) is a 32-bit Microsoft Windows NT based plant data analysis and integration tool. It is a predictive maintenance program that combines state-of-the-art performance monitoring techniques with computerized maintenance management. ICAS provides data acquisition and display, equipment analysis, diagnostic recommendations, and decision support information to plant operators and maintenance personnel. The system also provides user-defined performance alarms that alert the operator to machine problems. It provides the hybrid diagnostic system (HDS) diagnostic advisories that assist in diagnosing approaching failures and initiating the restoring process. The hybrid intelligent system is a fault-modeling environment that comprises both crisp logic and fuzzy logic rules.

The integration with ICAS required substantial electronics development in order to process, into a form compatible with ICAS, the acoustic emission and current signals collected during the normal and abnormal functioning of highpower radar tubes. An OPTO22 SNAP B3000 BRAIN unit was utilized to collect the data from the current and acoustic sensors. Two interface circuits were developed, one for each type of sensor, to interface with the ICAS software. **Figures 12** and **13** show the block diagrams for the developed electronics. The details of the electronics are beyond the scope of this paper. Further details on the ICAS interface and the electronics designed for this effort can be found in Ref. [8].

**53**

**7. Virtual sensor**

*Interface circuit for cathode current sensor.*

**Figure 13.**

polynomial expansion.

parameters X<sup>k</sup>

F = F(x1,x2,x3,…,xi) = ∑

where Cijkl are calculation coefficients and Xk

F = F(x1,x2) = a + bx1 + cx2 + dx1x2 + ex1

*Automated Classification of Microwave Transmitter Failures Using Virtual Sensors*

One of the main advantages of the ICAS software is that it allows mathematical manipulation and combination of inputs from real sensors. This is essential in the development of what has been defined in this report as a virtual sensor. The generalized concept behind the virtual sensor is that a characteristic signature of a failure, denoted by F, is a function of more than one parameter (x1, x2, x3,…,xi). Thus, the characteristic signature of the failure, F, can be written mathematically as

> *i*=1 *n* ∑ *j*=1 *n* ∑ *k*=0 ∞ ∑ *l*=0 ∞

number of sensor parameters. The function F can generally be represented by a

where the coefficients Cijkl are represented by a, b, c, d, …, and the functional

specifically require that the parameters have the same units or appear correlated at first appearance. Monitoring the value of F will therefore provide a measure of the system status and/or identify or differentiate failures. Using the virtual sensor formalism allows one to concatenate sensor information to provide more information than normally derived from either sensor alone or used in normal combination. An alternative approach to simply combining sensor data in the manner just described

are represented by x1 and x2. Note that this expansion does not

As an example, if the failure is a function of just two parameters, then

*CijklXi kXj*

and Xl

2

*<sup>l</sup>* (3)

correspond to each of n

x2 + fx1x2 + … (4)

*DOI: http://dx.doi.org/10.5772/intechopen.81652*

**Figure 12.** *Interface circuit for acoustic emission sensor.*

*Automated Classification of Microwave Transmitter Failures Using Virtual Sensors DOI: http://dx.doi.org/10.5772/intechopen.81652*

**Figure 13.** *Interface circuit for cathode current sensor.*
