Elma Instruments 5706445410286, Руководство пользователя

Страница: 24 / 36

Elma BM 251s-257s side 24
International electrical symbols
!
Caution! Refer to the explanation in this Manual
Caution! Risk of electric shock
Earth (Ground)
Double Insulation or Reinforced insulation
Fuse
AC--Alternating Current
DC--Direct Current
Cenelec directives
The instruments conform to CENELEC Low-voltage directive 2006/95/EC and Electromagnetic
compatibility directive 2004/108/EC
Product description
Note: Top of the line model is used as representative for illustration purposes. Please refer to your
respective model for function availability.
1. 3-5/6 digits 6000 counts LCD display
2. Push-buttons for special functions & features
3. Selector to turn the Power On or Off and Select a function
4. Input Jack for milli-amp and micro-amp current functions
5. Input Jack for all functions EXCEPT current (

A, mA, A)
functions
6. Common (Ground reference) Input Jack for all functions
7. Input Jack for 10A (20A for 30sec) current function
Analog bar-graph
The analog bar graph provides a visual indication of measurement
like a traditional analog meter needle. It is excellent in detecting faulty
contacts, identifying potentiometer clicks, and indicating signal spikes
during adjustments.
Average sensing RMS calibrated
RMS (Root-Mean-Square) is the term used to describe the effective
or equivalent DC value of an AC signal. Most digital multimeter use
average sensing RMS calibrated technique to measure RMS values of AC signals. This technique is to
obtain the average value by rectifying and filtering the AC signal. The average value is then scaled
upward (calibrated) to read the RMS value of a sine wave. In measuring pure sinusoidal waveform, this
technique is fast, accurate and cost effective. In measuring non-sinusoidal waveforms, however,
significant errors can be introduced because of different scaling factors relating average to RMS values.
True RMS
True RMS is a term which identifies a DMM that responds accurately to the effective RMS value
regardless of the waveforms such as: square, sawtooth, triangle, pulse trains, spikes, as well as distorted
waveforms with the presence of harmonics. Harmonics may cause:
1. Overheated transformers, generators and motors to burn out faster than normal
2. Circuit breakers to trip prematurely
3. Fuses to blow
4. Neutrals to overheat due to the triple harmonics present on the neutral
5. Bus bars and electrical panels to vibrate
JACK
JACK
!