Some details about digital oscilloscope that even senior engineers can ignore

 

A digital oscilloscope is an electronic measuring instrument. It can transform invisible electrical signals into visible images and facilitate people to study the changing process of various electrical phenomena. It is a great helper for most power engineers. But some engineers directly use the probe without checking whether the probe needs compensation or whether the oscilloscope needs calibration, which affects the final results. What factors need to be considered in using a digital oscilloscope? Here are the three details that may affect the analysis of the digital oscilloscope.

 

1/ Probe Self-Calibration

This function should be available in most digital oscilloscopes. The adjustment is to match the probe with the input channel. If the instrument is first operated and data of multiple input channels are displayed simultaneously, data may need to be calibrated vertically and horizontally to synchronize time base, amplitude and position. For example, calibration is required when there is a significant temperature change (> 5℃). Here are the steps:

  1. Disconnect any probe or cable from the channel input connector. Make sure the instrument is running and pre-heated for a while. Select “Self-Alignment” from the “R File” menu.
  2. On the Control tab, click “Start Alignment”.
  3. The results of each calibration step for each input channel are displayed on the Results tab.

 

2/ Probe Compensation Adjustment

This function should be available in any oscilloscope. Simple as it is, many engineers fail to do it and end up with the false results. So, probe compensation adjustment is recommended for taking accurate measurements.

  1. Connect the oscilloscope probe to the channel and press the PRESET button on the front panel (in the left panel setting area).
  2. Check the shape of the waveform shown. Whether it is over-compensation, insufficiency, or correct compensation?
  3. If the waveform is incorrect, adjust the probe.

 

3/ Determine the Effect of Power Insertion

Each power supply has an influence on the input power supply of the feed. The power cord in real life will never provide an ideal sinusoidal wave, but there will always be some distortion and unsatisfactory characteristics on the cord. Switching power supply brings a non-linear load to the power supply. Therefore, the voltage waveform and the current waveform are not exactly the same. The current is absorbed in some part of the input cycle and then generates harmonics on the input current waveform. It is necessary to measure the power quality at the input stage to determine the power consumption and distortion on the power line.

But to most engineers, these steps are very easy to be missed out. So, is there any digital oscilloscope that can save us from these troublesome steps? Absolutely yes! Recently, handheld oscilloscopes have been gaining popularity among engineers, technicians and  auto mechanicians. If you are an electrical engineer travelling a lot, it’s best to choose a portable digital oscilloscope.

Recommendation

We have got our own area of expertise and final comes down to DS213 from MINIWARE. DS213 is a “5-track, 4-wave line” digital oscilloscope for general-purpose electronic engineering task based on the ARM Cortex M3 core. It uses an FPGA to manage external ADC’s control and data cache modes. There are four application partitions for loading and upgrading up to 4 different application firmware. It also has an internal 8MB USB flash drive for storing waveforms and upgrading system firmware, making analysis clearer and more effective. With strong waveform processing capability, DS213 can automatically measure voltage, frequency, pulse width, and other parameters. Also, the oscilloscope code application layer is open-source so that users can develop firmware if needed. What excites you most must be the simple operation. It has an automatic calibration function and the probe needs no compensation. Powered by a lithium battery, it is convenient to carry around. All these features make DS213 aptly-named top pick as a portable digital oscilloscope.