The present invention relates generally to electrical test probes for testing instruments and specifically to an identification system to associate a probing head to a specific channel of a testing instrument.
An electrical test probe generally consists of a probing head, a cable, and a connector. The probing head may have an integral or replaceable probing tip that is suitable for making an electronic contact with electrical components. The probing head is attached to a first end of the cable and the connector is attached to the opposite end of the cable.
Electrical test probes are used to provide an electrical connection between electrical components and testing instruments such as oscilloscopes and other measuring, monitoring, diagnostic, and signal processing instruments. Most testing instruments have multiple channels, each channel having its own input. An electrical test probe may be attached to one or more channel inputs using the test probe""s connector. As an electrical component is probed with an electrical test probe, its signal registers on the testing instruments. Because multiple electrical test probes may be used simultaneously, it is important to be able to identify which signal is emanating from which electrical test probe.
A set of colored bands, known as xe2x80x9cchicken bands,xe2x80x9d is old technology that has been used to associate a signal from a test probe with the visual signal being displayed on the testing instruments. To use chicken bands, one band is attached to the cable substantially adjacent the probing head of a test probe and a second band of the same color is attached to the cable substantially adjacent the channel input of the testing instruments. One problem with chicken bands is that the user must attach the bands individually, which is extra work and adds the possibility of human error. Another problem is that chicken bands have a tendency to fall off and get lost.
Newer technology that has been used to associate a signal from a test probe with the visual signal being displayed on testing instruments is a set of colored rings on one or both ends of the cable of a test probe. The colored rings adjacent the probing head can be exchanged to correspond to a corresponding exchanged color ring adjacent the testing instrument channel input. Since the rings are around the cable, there is no problem with losing chicken bands. There is, however, the problem of the additional work of exchanging the rings and the possibility of human error.
Some testing instruments are equipped with visual signals (such as the traces on a signal display) that are color-coded to a particular channel input. For example, recent LeCroy Corporation oscilloscopes have a distinctive color permanently assigned to the displayed trace of each channel. Since the visual signals are color-coded, only the probing head needs to be identified. The user attaches a chicken band or exchanges a colored ring to correspond with the visual input signal. This eliminates the need to exchange half of the rings or attach half of the chicken bands.
U.S. Pat. No. 6,052,807 to Nygaard, Jr. is directed to a device (the xe2x80x9cNygaard devicexe2x80x9d) that is able to identify the channel of a particular probe from among a plurality of test probes. Each test probe emits its own signal (xe2x80x9cuncommon ID signalxe2x80x9d). The multi-channel measurement equipment identifies the probe-to-channel correspondence when a test probe is touched to an xe2x80x9cidentification terminal.xe2x80x9d When the user touches the probe to the identification terminal, the identification of the associated channel is indicated by illuminating an annunciator light or displaying a numerical indicator (one or more LED or LCD digits), or it may involve displaying a message on a screen. The LED, LCD, or message is on the multi-channel measurement equipment. In other words, the Nygaard device requires the user to remove the test probe from a circuit board and to look at the multi-channel measurement equipment. This can be distracting, can cause difficult connections to be lost, and can be time-consuming.
The automatic probe identification system of the present invention improves on testing instruments that are equipped with visual signals (such as the traces on a signal display) that are color-coded to a particular channel. Specifically, the automatic probe identification system of the present invention automatically identifies an electrical test probe as being associated with a particular channel. A single electrical test probe may be connected to any channel of a testing instrument and automatically indicates to which channel it has been connected. An additional benefit of this system is that the LED used in one preferred embodiment provides additional illumination for shadowed or dark places.
Specifically, an automatic probe identification system of the present invention includes a testing instrument and at least one test probe. The testing instrument preferably has at least one input channel, each input channel being visually represented by a unique channel identification such as a colored trace. The test probe has a probe identifier such as a full-spectrum LED for selectively visually representing a unique probe channel identification. The probe identifier visually represents a unique probe channel identification corresponding to the unique channel identification of the input channel to which it is coupled.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.