RPM-8000-PRO |
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RPM-8000-PRO offers a discerning solution for
automotive RPM measurement without an additional sensor: the practical
instrument is simply connected via a standard jack to the cigarette
lighter socket and the RPM is shown directly on the LCD display. You even
have the choice to output the data as an analog voltage (1 Volt per 1000
rev/min) or as a digital pulse sequence (TTL). The smart measuring
principle is based on an analysis of the ripple balance of the supply
system, characteristic for all automotive alternators. The frequency of
this ripple amounts to about 100 to 120 pulses per engine rotation and
therefore delivers good dynamic measuring results.
Though the frequency is proportional to the engine RPM, it also depends on the gear transmission ratio from crankshaft/alternators and on the number of alternators poles and phases. This makes the calibration of the input signal to the actual measured RPM necessary. The latest version of the RPM-8000-PRO now offers two elegant options:
• Internal calibration: The internal calibration assumes a steady engine RPM of 2000 rev/min, which can be monitored by the automotive tachometer. By pushing the “Cal. Int” button the calibration starts, whereby the instrument assigns the actual measured pulse frequency to speed “2000” and outputs the actual engine RPM to the LCD display. • External calibration (option): A laser RPM ”RPM-LASER-CAL” is needed for this option. A reflector tag is mounted on the crankshaft and scanned by laser beam. The TTL output of the laser instrument is connected via cable to the “Ext. Cal In.” input of the RPM-8000-PRO and delivers one pulse per rotation. By comparing the pulse sequence with the measured pulse frequency, the instrument calculates automatically the relationship between ripple balance and speed. Identical displays on laser and RPM-8000-PRO signal successful calibration (also shown by luminescent LED’s). The measuring range of the analog output can be varied on demand via jumpers (e.g. to 0.5, 1.0 or 2.0 Volt per 1000 rev/min). The TTL output can also be scaled with a frequency factor of 1:8 or 1:16 – and therefore adapted to the resolution ability of attached measuring systems. For testing purposes this “factor” between speed and TTL frequency can be output, instead of the speed, to the LCD display by pushing the “TTL” button. The instrument saves the calculated calibration data in non-volatile memory until the next calibration. |
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For more information see PDF data sheet |
