8B33 SCM Measures True RMS

The 8B33 is part of  Dataforth Corporation's family of miniature SensorLex® 8B isolated analog signal conditioners and designed specifically for measuring True RMS values of input signals.

Each 8B33 True RMS input module provides a single channel of AC input which is converted to its True RMS DC value, then filtered, isolated, amplified, and converted to a standard process voltage or current output.

Key 8B33 features and specifications:

• Interfaces to RMS Voltage (0-300V) or RMS Current (0-1A)
• Designed for Standard Operation with Frequencies of 45Hz to 1000Hz (Extended Range to 10kHz)
• Compatible with Standard Current and Potential Transformers
• ±0.25% Factory Calibrated Accuracy
• 1500Vrms Transformer Isolation
• Input Overload Protected to 350Vrms Max (Peak AC & DC) or 2Arms Continuous
• ANSI/IEEE C37.90.1 Transient Protection
• 120dB CMR
• Industry Standard Output of 0 to 5VDC
• -40°C to +85°C Operating Temperature Range
• CE Compliant
• Hazardous Location Certifications Pending

Download the 8B33 datasheet and block diagram.

RMS, or Root Mean Square, is a key measurement of an AC signal. In practical terms, it is the equivalent DC signal that produces the same amount of heat in a given load. Therefore, it directly relates to signal power. For purely sinusoidal signals, the RMS value is the familiar peak amplitude divided by the square root of two. However, for signals comprised either of harmonics or of noncoherent content, this expression becomes increasingly invalid as the harmonic content or noncoherency increases. With these types of signals, therefore, the value is typically given in terms of a waveform's Crest Factor, which is the ratio of its peak amplitude to RMS amplitude. Crest factors start at one for DC or square waves and increase for more "pointed" signals.

By reducing the dependency on sinusoidal purity, True RMS conversion allows accurate measurement of signals ranging from pulses to complex nonperiodic waveforms. The conversion core circuit used in the 8B33 is similar to those found in high-end digital voltmeters.

Like all modules in the SensorLex® 8B family, the 8B33 is fully encapsulated and thus able to withstand harsh environmental conditions while providing fully functional Instrument Class® performance. Originally developed in response to customer requests worldwide for smaller, lower cost isolated signal conditioners, the SensorLex® 8B is housed in a miniature 1.11" x 1.65" x 0.4" (28.1mm x 41.9mm x 10.2mm) module.

The SensorLex® 8B product line now includes 19 family groups and a total of 123 different models.

Their small size is ideal for embedded or portable applications such as mobile test stands, COTS military and defense applications, miniaturized security and surveillance systems, embedded process controls for semiconductor manufacturing equipment, and virtually any other embedded industrial data acquisition system.

About Dataforth

Dataforth was established in 1984 and is the world leader in data acquisition, signal conditioning and data communication products for industrial applications. Worldwide, our electronic data acquisition, signal conditioning, and data communication products provide rugged signal and data integrity and wide spectrum accuracy. All Dataforth products are manufactured in the USA and have been RoHS Compliant since 2006. The Dataforth Quality Management System is ISO9001:2008 registered.

For additional information, call 800-444-7644 toll-free, email sales@dataforth.com, or visit our website at www.dataforth.com.