Event Detector Glossary
Event Detectors are designed for automatic test operation and data collection over extended periods of time without operator assistance. All Event Detectors share similar operating features. The following glossary defines terms specific to the Event Detector test methods:
Event Detectors: class of electronic test instruments used to monitor interconnect resistance or continuity during environmental stress-testing; capable of detecting short duration events/failures according to precisely defined test specifications. Also known as "chatter detectors" or "glitch detectors". For relay testing, they are often termed "contact bounce detectors" or "cross-over detectors". See Continuous Monitoring, below.
Test Specimen: the physical item that is being tested for electrical interconnection failure. Typical examples of test specimens include solder joints, separable connectors, etc. Each test specimen may be comprised of a single specimen or a short chain of specimens through which a simple continuity loop is formed for sense current to flow. For "normally-open" test-specimens, the continuity loop is formed only when a "short" (event) occurs.
Continuous Monitoring: characteristic of Event Detector electrical monitoring. Event Detectors are comprised of multiple independent, resistance/continuity monitoring channels, where each test specimen(s) is monitored continuously for the entire duration of the test. Each channel has its own independent memory. Event Detectors utilize hardware-intensive parallel architecture for detection of very short duration events with continuous monitoring. This contrasts to scanning systems and data loggers which cannot offer continuous monitoring. Scan systems actually monitor only one test specimen at any instant in time while all other channels are unmonitored and thus do not meet the requirement for continuous monitoring.
Resistance Threshold: the sample resistance below which, no events can be detected. Event Detection is defined with respect to the selected resistance threshold. The resistance threshold is adjustable over a limited range, specific to each type of Event Detector. An event is only detected when the resistance of a test specimen (sample) exceeds the resistance threshold for at least as long as the Minimum Event Duration, described below. Often Event Detection is considered in terms of "opens", "intermittents", and "shorts" with a somewhat vague specification of the associated resistance threshold involved.
Event: specimen electrical resistance that exceeds the threshold resistance for at least the minimum event duration; otherwise known as "fault", "failure", "open", or "intermittent", the term "event" is more general and accurate. The electrical resistance of all specimens under test is compared to a user-selected threshold resistance. If the specimen resistance exceeds the threshold resistance for normally closed channels (or drops below the threshold resistance for normally open channels) and is sustained for at least the Minimum Event Duration setting, an event is flagged. Once a channel has detected an event, no further events will be detected on that channel until the event data is collected by the polling computer.
Polling: data communication for downloading most recent event data from an Event Detector to the data collection computer. The host computer "polls" the Event Detector to transfer the event data stored in the Event Detector to the host computer (PC compatible) via a serial (RS232) communication port. The serial polling command to the Event Detector causes the event data to be communicated back to the computer. Each poll erases all existing events from the Event Detector channel memories thereby "resetting" all channels. The data collected from the Event Detector(s) is stored on disk with the associated channel number, cycle, date, time, etc. Data collection, storage, and analysis functions are all controlled by the software package WinDatalog included with all Event Detectors.