Introduction
The Model 460 3-channel Hall effect gaussmeter is the best choice for applications requiring 3-axis measurements or three simultaneous single axis measurements. The Model 460 combines the performance of three gaussmeters into one package, making it an excellent value for materials analysis and field mapping applications. The large vacuum fluorescent display shows readings for all three channels simultaneously as well as vector magnitude or differential readings. The full-function keypad provides easy access to measurement features.
Measurement modes
The Model 460 operates in DC, RMS, and Peak modes, with superior accuracy and resolution in DC measurement mode. Measurements to 5¾ digits are possible due to the low noise floor. With low noise and high stability, the Model 460 is ideal for multiple-axis field mapping applications. Changing fields that are often used in material analysis systems can be measured on all three inputs up to 18 times per second over the computer interface, with excellent resolution.
Best suited for fringe field measurements or measurement of magnets and solenoids driven at line frequency, RMS mode measures periodic AC fields from 10 Hz to 400 Hz. Instrument circuitry accommodates wave forms with crest factors up to 7, with true RMS conversion.
Peak circuitry in the Model 460 captures single event peaks or monitors the peak amplitude of periodic wave forms from 10 Hz to 400 Hz, with reproducible single peak measurements down to 5 ms rise time. Instrument software accommodates indefinite hold time with no decay. The Model 475 DSP gaussmeter is a good choice if faster peak or RMS measurements are required.
Range and resolution
When used with appropriate probes, the Model 460 3-channel gaussmeter offers full scale ranges from 300 mG to 300 kG. A different range can be used with each input. With 5¾-digit resolution, DC field variations approaching 0.010 mG can be detected; in larger DC fields, resolution to one part in 300,000 is possible. For RMS and Peak measurement, resolution is 4¾ digits or one part in 30,000 because in these modes environmental noise is more difficult to separate from the desired signal. The filter feature of the Model 460 improves resolution in noisy environments by taking a running average of field readings. DC mode requires filtering to achieve 5¾-digit resolution.
Interface
The Model 460 is equipped with both parallel (IEEE-488) and serial (RS-232C) computer interfaces for command and data exchange; maximum reading rate can be achieved with the IEEE-488 interface. Nearly every function on the Model 460 front panel can be performed via computer interface. The Model 460 also includes one corrected and three monitor analog voltage outputs. Corrected for sensor linearity, offset, and temperature effects, the corrected output is a DC voltage proportional to the display reading. It is generated by a digital-to-analog converter programmed at the update rate of the Model 460, with software error correction. Corrected output is compatible with the Model 460 vector calculation software. The three monitor outputs are real time analog voltages proportional to each input’s field; uncorrected, they provide output across the full DC to 400 Hz bandwidth at real-time speed.