Built-in-test

Some scales have a software feature whereby a certain geographical region is identified on initial configuration, and the software then makes the appropriate correction. Some high performance balances have built-in test weights for initial (and periodic) calibration. 

In areas where the possibility of fire is the greatest, a high speed ultraviolet detection system is employed. The ultraviolet eyes detect the presence of a flame and are interconnected with a high speed water deluge system. In some areas the fire detection devices have process shutdown capabilities. The detectors are situated such that the entire hazardous area can be monitored at all times. They are equipped with air shields that not only cool the detector but also blow clean air across the face of the lens, keeping any dust from accumulating on the lens, which assures detection capability. Further, the detectors have a built-in test lamp which serves as a check of... 

COTS software functionality disabled by configuration is not redimdant code in the truest sense, on the basis that the disabled software is intended to be enabled according to the need of a particular implementation. Examples of where functionality may be disabled without creating redundant code include hbrary software (e.g., printer driver routines or statistical functions), built-in testing software, and embedded diagnostic instructions. 

Computers acquire, assess, process, and store operational data from the analyzers. Many computers include built-in test equipment that monitors instrument functions for correct execution and reacts to unproper function by recording the site and nature of the malfunction. 

The testing concepts described so far make explicit use of the fact that additional drive electrodes, together with those used to capacitively sense a primary sensor input signal, may be used for built-in tests. Design for test concepts therefore appear to be limited to the class of sensors employing reversible transducer mechanisms (i.e., capacitance or piezoelectricity) and to their processing sequences. 

In addition, the sensor principle permits a complete self-test of the sensor, including the rotary oscillator (BITE = built in test). For the self-test, the rotary oscillator is deflected electrostatically via additional electrodes between the oscillator and the substrate. The sensor structure reacts to this in precisely the same way as if a turning movement has occurred the sensor detects a turning-rate signal. Testing is also possible during operation and thus permits a permanent function monitoring. 

Continuous Test % of detection of failure immediately detected by equipment BITE (Built-In Test Equipment) ... 

The enterprise assesses the testability of design alternatives to determine built-in test (BIT) and/or fault-isolation test (FIT) requirements to support operational or maintenance considerations. BIT-FIT mechanisms should be provided for those elements that are normally maintained by the operators, customer, or field support engineers. BIT-FIT can be used for diagnostic operations to support lower-level maintenance actions. 

Addition of built in test and some user/extemal communications facilities with supporting evidence of sufHcient rigour to achieve AEL 2. 

The safety specification will need to elucidate how such faults are to be handled including a description of any necessary self-monitoring and built-in tests for malfunction together with the form of the user warning to be issued. Having identified the safety-related functions, the required safety level must... 

Built-In Tests (BITs) are widely used in mechanical and electronic systems to find whether system faults occur (Malcolm 1982, Jager 1984), aiming at reducing the time of fault detection, raising system availability and reliability (Steininger 2000). However, the false alarms phenomenon is always a troublesome problem in BIT applications a BIT can make a noise when a fault does not occur, resulting in extra detachments and inspections (Anderson Laskey 1988, Westervelt 2004, Khan et al. 2014). The operators may lose heart towards the unreliable indications, or feel disturbed and annoyed towards the nuisance alarms (Adnan et al. 2011). 

This paper introduces a designing concept of adaptive detection threshold for a Built-In Test (BIT). 

Allen D., 2003. Probabilities associated with a built-in-test system, focus on false alarms. In AUTOTESTCON 2003. IEEE Systems Readiness Technology Conference. Proceedings IEEE, pp. 643-645. 

Westervelt K., 2002. F/A-18D (RC) built-in-test false alarms. In Aerospace Conference Proceedings, Vol. 6, pp. 2961-2970. 

The IC was fabricated in a 0.35-p,m 4M2P CMOS process and the chip size is 8.8 X 7.2 mm (Fig. 50). The measured power consumption of the entire chip is 6 mW from 1.65 V when operating in streaming mode. The 8 front-end blocks consume 50% of the total power. The UWB TX consumes 1.6 mW with PPM modulation. The power consumption of the DSP block is only 0.1 mW. Waveforms at the output of amplifier, spike sorting, UWB TX, and UWB RX were monitored by the built-in test circuits (Fig. 51). 

Clearly, maintenance activities inherit the hazards of the system on which they are performed and such hazards are usually independent of whether the system is or is not safety-critical however, certain aspects of maintainability can induce additional hazards. For example, if Built-In Test Equipment (BITE) is used, it must be remembered that a failure of the BITE can induce a system failure. Similarly, external Special Test Equipment (STE) and Maintenance Assist Modules (MAMs) must not only be designed so that their failure does nor bring down the system but also so that their use does not introduce sneak conditions [11], leading to transient operational failures. It is thus vitally important that the design of such ancillary systems be co-ordinated with that of the main system and that they are also included witliin the scope of the system safety analysis. Finally, it must be remembered that the inclusion of BITE will adversely affect the system s reliability because the component-count will be increased thus, BITE should always be examined in an availability analysis, to ensure that the improvement in maintainability offsets the loss of reliability. 

The C-factor comprises the percentage of failures in modules, software, external wiring, internal wiring, cables, interconnections and other functions that are detected by the built-in test functions, or by a suitable test program. It can be expressed in a probability or in a factor that is always smaller than 1 (e.g. C = 0.95) or as a percentage (e.g. 95%). 

---