Model RH520 humidity and temperature chart recorder provides simultaneous numerical and graphical displays of humidity (20-95 percent rh) and temperature (-20° to 140°F). The basic accuracy of the unit is ± 3.5 percent rh and ±2.8° (±1°C). It also calculates dew point. The multiple graphic displays are cursor controlled and have adjustable X-Y axis resolution, which allows the user to monitor both temperature and humidity within a user-specified range. The sample rate is adjustable from 0.1 second to 200 minutes per sample, permitting daily, weekly, or monthly graphs. The internal memory records up to 49,000 readings with time and date, which can be transferred to a PC for data recordkeeping, analysis, and printing. Features include a detachable probe that extends up to 1 meter and high and low set points that trigger audible and visual alarms. An external remote alarm module is available.

Extech Instruments, 285 Bear Hill Rd., Waltham, MA 02451; 781-890-7440; 781-890-7864 (fax);

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