Using the Datalogger

Numerous test and measurement applications require data acquisition over a long time duration. Instead of milliseconds of measurement time, you may need tens of minutes or even hours of data. Normally, a data acquisition system is used for this type of application, which may require developing software and troubleshooting code. SIGLENT has added a data logging mode to the four-channel SDS1000X-E oscilloscope series that makes it easier than ever to collect long-time duration data. Models  SDS1104X-E and SDS1204X-E have a data-logging feature that was added in firmware revision 6.1.37R2 and OS Rev 2. The SIGLENT Data Logger continuously records original sampling points and measurement values.

Before using the Datalogger, you may want to set the clock on the oscilloscope. You can set the date and time manually or use an NTP server to set the date and time automatically as explained here:   https://siglent.tawk.help/article/ntp-synchronization-sds1000x-e

In the image below, a SDS1000X-E oscilloscope with an analog signal applied to each of the four channels is shown.

The Data Logger consists of a Sample Logger and a Measure Logger

Logging with the Sample Logger

The Sample Logger continuously samples and stores measurement points. It is ideal for the long-time observation of low-speed signals. Because the original points are recorded for a long time, the amount of data can be very large. Since the DDR memory of the oscilloscope is limited, the sampling points are saved to the internal flash of the machine or an external U disk (USB memory device) in real-time. After stopping the acquisition, the user can not only look back at the sampled points on the oscilloscope but can also analyze the saved data on a computer.

Press Record to get to the Record menu

Press Settings and select rate to select from sample rate options. Note that the maximum recordable time is calculated from the sample rate and available memory and conveniently displayed on screen.

The maximum file storage size for a data logging event is 2 GB and for the measurement logger it is 14 Mpts. Internal memory may be used to store the data, but internal memory capacity only allows smaller logfiles to be created. Use a 2 GB or larger USB stick and set the datalogger to Record to External in order to store the longest possible datalogging event. The logging process will terminate when the maximum file storage size of 2 GB is reached.

Sample rate is selectable in a 1-2-5 scheme ranging from 1 Sa/sec up to 25 kSa/s. At this highest rate, the data from one channel would reach the 2 GB limit in a little over 23 hours. Data may be logged from any/all of the four analog channels. The data logger does not store digital channel samples that you may also have set the oscilloscope to acquire using an SLA1016. All channels that are logged use the same sample rate. Each channel that is logged reduces the amount of time that the data may be stored. So, continuing the 25 kSa/s example, four channels could be logged for a little under 6 hours.

Here, we have chosen the maximum sample rate and set Record to External. The log FileName can be automatically generated as shown below, or assigned a new name.

Data logging is initiated by manual press of the datalogger Start Button. Datalogging is terminated by the manual press of the Stop button or when the storage maximum has been reached.

The Start button switches function to a Stop button when datalogging is in progress.

Recall a logged file in the Sample Logger

The Sample Logger can recall samples from a U disk or flash memory to the scope where they can be viewed and analyzed. The DDR of the oscilloscope is limited. If the waveform data exceeds the DDR capacity, the U disk will be read during operation, so please do not pull out the U disk when analyzing the samples.

or

Use the time base and delay knob to adjust the waveform.

Select a channel and use the X and Y cursors to measure.

Analyzing a Sample Logger file on a PC

The file format of a the datalog is binary and the filename ends with .slg. This data can be converted to CSV type file by using the Binary to CSV program available here.

You can move the USB drive to a computer and use the Binary to CSV program to convert it for analysis.

Data Logger: Measure Logger

The Measure Logger collects measurement samples and shows the trending over time of low-speed signals. Because the amount of measurement data is relatively small, in order to process it quickly, the data is logged in the oscilloscope memory. After logging is complete, the data can be saved into the internal flash or external U disk, and imported to the PC.

Press Measure to select a measurement type for each channel.

Then open Datalogger and select Measure Logger.

Select Settings 

Use the Intensity/Adjust (Universal knob) control to select a Log Interval in the range 0.1 seconds to 10 minutes.

The Start button switches function to a Stop button when datalogging is in progress.

Pressing Stop enables the Save/Recall menu button.

In order to analyze on the PC, the logged file in the flash can be exported to a USB drive. Use the Binary to CSV program available here to convert it to CSV for analysis. Also, the oscilloscope provides a tool for converting logged files (.mlg) to CSV: file converter. You can export this tool in the save/recall menu of the oscilloscope or on the web page.