Isolation oscilloscope incorporating the latest broadband isolation patented technology

1: Measurement from mV to kV, complete isolation between channels

About "floating ground" measurement

The input part of the SHS1000 series oscilloscope adopts patented broadband isolation technology. The two input terminals of the standard dual-channel input oscilloscope are grounded, while the two input terminals of the SHS1000 series oscilloscope are completely isolated, which means that voltages with large differences can be safely connected to the two input terminals at the same time, and the isolation safety level between the input terminals is as high as CAT II 1000V, CAT III 600V. CAT is the safety level of the measuring instrument defined by IEC. It not only stipulates the maximum rated voltage of the measuring instrument, but also stipulates the environment in which the instrument is used, that is, the overvoltage classification-CAT III is more stringent than CAT II. The floating voltage of each input terminal of the SHS1000 series oscilloscope, that is, the maximum voltage between the terminal and the ground, is as high as CAT II 1000V and CAT III 600V, which can meet most floating ground measurement environments.

Traditional oscilloscopes are limited to making reference ground measurements because the ground wire of most oscilloscopes (the probe ground wire or the BNC shell) is connected to the protective ground. If the ground wire connected to the oscilloscope shell is connected to the earth through the ground wire in the AC power cord, this means that all measurements must be made relative to the ground, which limits the application of typical oscilloscopes to measuring the voltage between two points that are not grounded. This measurement is usually also called "floating" measurement. Since the voltage between the common-mode voltage of the signal line and the ground may be as high as hundreds of volts or even thousands of volts, this measurement must be faced in power electronic circuits such as switching power supplies, motor drives, and rectifiers.

Some engineers disconnect the ground wire of the power cord or use an isolation transformer to "float" the oscilloscope. The probe ground wire is connected to one of the test points for measurement. The common-mode voltage of the test point may be as high as hundreds of volts. At this time, the oscilloscope shell will also carry high voltage, posing a threat to users, units under test, and instruments. In addition, it violates industrial health and safety regulations. In addition, when AC-powered instruments float on the ground, a large parasitic capacitance will appear, and floating measurements will oscillate, and the measurement results obtained will also be poor. Professional oscilloscope manufacturers strictly prohibit this kind of floating measurement. For some battery-powered general-purpose oscilloscopes, such as TDS3000B, floating measurements can be performed, but only 30VRMS safe floating measurements can be performed.

In addition, for this kind of floating measurement, users can also choose to use isolated differential probes to solve it. This is a safe and reliable way to enable grounded oscilloscopes to perform floating measurements, but it puts forward new requirements for the cost and complexity of the measurement equipment. It may require an independent power supply, and its gain and deviation characteristics will also be brought into each measurement. Oscilloscopes equipped with differential probes focus on performance and safety (bandwidth, isolation) at the expense of portability and cost.

Using an isolated oscilloscope, floating measurements can be performed directly, which is safe and simple. The SHS1000 series handheld oscilloscope is a truly isolated oscilloscope. The BNC input reference is completely isolated from the ground and the channels are completely isolated. It can achieve the safety level of CATII 1000V and CATIII 600V. It supports battery power supply, handheld, light weight, easy to carry, and suitable for outdoor portable testing.

SHS1000 Series Isolation Oscilloscope Isolation Indicators

The SHS1000 series handheld isolation oscilloscope uses patented broadband isolation technology to achieve isolation of signals with bandwidth from DC to 100MHz, dual-channel input, sampling rate of 1GSa/s, 2Mpts deep storage, and vertical range from 5mV/div to 100V/div. The input voltage on the BNC side can reach CATII 300V, CAT III 150V. Using the 10:1 probe that comes with the instrument, the voltage that the probe can detect can reach CAT II 1000V and CATIII 600V.

Referring to the figure below, the circuits of channel 1 and channel 2 are electrically isolated, and the digital acquisition circuits are also electrically isolated through an isolator. The isolator in the figure includes isolation of broadband signals and isolation of power supply. The broadband signal isolation uses patented broadband isolation technology to achieve isolation of signals from DC to 100MHz (-3dB), and achieves good flatness within the band.

Oscilloscope functional block diagram

The circuits of channel 1 and channel 2 are completely electrically isolated, and the digital acquisition circuits at the back end are completely electrically isolated. Whether powered by an AC adapter or a battery, the floating voltage that can be detected by the BNC shell or the ground terminal of the probe, and the isolation voltage between channels can reach CAT II 1000V and CAT III 600V.

Refer to the figure below, the measured voltage and floating voltage at the probe input or BNC input of the SHS1000 series isolated oscilloscope.

Probe, input voltage diagram at BNC

In-band flat graph

Amplitude-frequency response of SHS1000 series oscilloscope

Switching power supply floating ground test

Typical switching power supply schematic

Use SHS1000 series oscilloscope and Fluke199 oscilloscope to measure the voltage waveforms of Vgs and Vds of T2 MOS tube in the above schematic diagram. [page]

Vgs, Vds measurement waveforms (measured by SHS1000 series isolated oscilloscope).

Vgs, Vds measurement waveforms (measured by Fluke 199).

2. Deep storage

SHS1000 series isolated oscilloscopes can store up to 2Mpts of data, which is the highest memory depth in the industry.

3. Measurement and spectrum analysis

Support FFT analysis

Oscilloscope FFT interface

Automatic measurement supports automatic measurement of 32 parameters

Oscilloscope automatic measurement interface

4: Trend Chart

Oscilloscope Trend Chart

The oscilloscope trend chart is the process of saving the measured parameters of the waveform in memory and then displaying them on the screen in oscilloscope mode. It can support the trend display of 2 parameters at the same time.

Oscilloscope trend chart interface

The oscilloscope trend chart supports two display modes (full display and normal). In full display mode, the trend of all measured parameter values ​​recorded in the memory can be displayed on the screen. During the display process, the display effects in the horizontal and vertical positions will be adjusted dynamically. In addition, it supports cursor and zoom functions. According to the different positions of the cursor, the corresponding measured values ​​and relative time will be displayed. The standard for zooming is also based on the cursor position as the center for zooming; in normal mode, the latest recorded points (up to 300 points) are displayed on the screen. During the display process, only the display effect in the vertical position can be dynamically adjusted. In addition, the cursor function is supported.

The measured values ​​stored in the memory can be exported to a U disk for secondary development or data analysis.

The recording length is 815400 points, and the recording time is greater than 24 hours.

Multimeter trend chart

The multimeter trend chart is the process of saving the measured values ​​obtained from the multimeter in the memory and displaying them on the screen in the multimeter mode. Like the oscilloscope trend chart, the multimeter trend chart supports both normal and full display modes. [page]

Multimeter trend chart interface

Supports 8 sampling rates. Select different sampling rates to observe the changing trend of measured values ​​in different time periods.

There are two ways to record measured values ​​(manual recording and automatic recording). In manual recording mode, you need to press the "RECORDER" button once to record a measured value; in automatic recording mode, the measured value will be automatically recorded at fixed time intervals.

The measured values ​​saved in the memory can be exported to a USB flash drive for secondary development or data analysis.

The recording length is 1461600 points. Select different sampling rates, and the recording time is: 40 hours and 36 minutes (10Sa/s), 81 hours and 12 minutes (5Sa/s), 203 hours (2Sa/s), 406 hours (1Sa/s), 812 hours (0.5Sa/s), 2030 hours (0.2Sa/s), 4060 hours (0.1Sa/s), 8120 hours (0.05Sa/s).

Five: Waveform recorder The

waveform recording function is mainly a function for continuously recording waveforms. This function works on the oscilloscope scanning time base, that is, in the range of 100ms/div to 50s/div. It can store up to 7M points of waveform data, and the longest recording time is 17 hours and 20 minutes (50s/div time base) when recording in memory. The maximum storage capacity is 4GB when storing in a USB flash drive (the longest recorder time is 29641 hours, 50 minutes and 40 seconds). The recorded waveform can be replayed at will and can be scaled to any time base gear and any voltage gear (2.5NS – 50S; 2mv – 5v) for users to observe the waveform details. When two channels are recorded at the same time, the maximum sampling rate can reach 25KSa/s, and the display has a full frame mode and a point-by-point mode.

The recorder function provides USB flash drive storage and memory storage, and also provides the function of saving and displaying at the same time. When the user stops the recorder manually or the recorder storage area is full and stops automatically, the recorder can provide waveform playback function and waveform data transfer function. The recorder function described above realizes the seamless connection of waveform storage and display.

At present, when the oscilloscopes on the market record waveforms, the waveform data acquisition unit and the processor will be idle for a period of time, which makes the time interval between each acquisition cycle of the waveform data acquisition unit longer, thus causing dead time. The recorder can record the waveform uninterruptedly for a long time, eliminating the dead time, so that the recorded waveform is a seamless waveform, thus providing customers with the function of observing subtle changes in the waveform.

6: Multimeter The

multimeter mode can measure DC voltage, AC voltage, DC current, AC current, resistance, capacitance, diode, on-off function;

DC voltage measurement interface

AC current measurement interface

Resistance measurement interface

6000-word multimeter range:

DC voltage (-1000Vdc—1000Vdc) , AC
voltage (0—750Vac)
, DC current (0—10A),
AC current (0—10A)
, resistance (0—60MΩ)
, capacitance (40nF—400uF)
, diode (0—2V),
continuity measurement (less than 50Ω) .

The control terminal ground of the multimeter is connected to the ground of the digital acquisition circuit of the oscilloscope. The signal input terminal ground of the multimeter is electrically isolated from the ground of its control circuit through an isolation device. The electrical isolation level is CAT II 600V and CAT III 300V.