• Raw data recording up to 200 kS/s
• Internal 1 TB SSD (continous recording up to 7 days @ 50 kS/s)
• 16 channels
• Up to 600V Using MSI2-V-600 Smart Interface Module
• User-friendly, Windows operating system
• Mixed-signal approach (temperature, pressure, humidity etc.)
• 15.6“ multi-touch full-HD display
• Portable with carrying handle (weight 7.3 kg)

                                                            

In addition to the usual task of measuring electrical power, the PU[REC] can also be used for cloud-based monitoring. A well-known manufacturer of commercial kitchen appliances equipment uses the PU[REC] in a cloud-based solution for 24/7 power quality monitoring on 3-phase ohmic-capacitive loads.                                        

                                                            

The diagram above shows the entire cloud-based monitoring approach starting from DAQ (data acquisition), including sig- nal conditioning and visualization with DEWETRONs own measurement software OXYGEN, up to storing the measurement data in small one-minute files on the SSD (solid state drive) in the so-called multifile mode and finally uploading these files automatically to the cloud in the background.

                        

For the cloud upload a network connection is required. This is easily done since Windows (or Linux, if desired) is running on the PU[REC]. Simply connect it to your LAN as you would with a desktop PC or notebook.

 

                                                            

The measurement data will be saved as a *.dmd (DEWETRON measurement data) file. This data type stores each value sampled by the ADC (analog to digital converter). A conversion to another data type such as *.CSV (comma separated values) or *.MAT (matlab data) requires a conversion of the samples to 32-bit IEEE-754 floating point numbers. The *.dmd format will keep file sizes small and processing speed fast.

                        

OXYGEN can also be used to view the recorded data and as a post processing tool. Subsequent math operations, formu- las, filters, statistical analysis and more can be added. These calculations can be added before and also after recording in the post-processing.           

                                         

                                                            

As already mentioned, OXYGEN is the measurement and recording software running on the PU[REC]. The figure above shows the Power Group instrument of OXYGEN which displays the electrical quantities including amplitudes and phase shifts of all phases.

                                           

                                                            

Multiple ways of presenting these quantities, such as phasor diagrams, tables and bar charts for harmonic and interhar- monic distribution can be selected.

                                                            

Recording multiple 3-phase power groups at high sample rates accumulates a lot of data. Saving the raw data of 6 volta- ges and currents with a sample rate of 200 kS/s will fill up the internal 1 TB storage in about 3 days. To avoid this problem, multiple solutions are available. A simple way is to delete the measurement files after the upload to the cloud is comple- te. Another, maybe more elegant, solution is to only record with a high sample rate on fault or alarm condition. To do this, a triggered recording can be set up in OXYGEN to only save raw data if one or a logical combination of conditions such as a dropped effective value of a voltage channel or a too high third harmonic in the current is met. This will also reduce the amount of uploaded data when there are little to no changes in the power values.

                        

Natively, the 16 female 9-pin D-SUB inputs are rated for ±10 V. To handle power measurements up to 600 V DEWETRON designed its own MSI (Modular Smart Interface) adapters for this exact application. Current transducers such as the LEM LF 210-S are used for the current measurement. To supply these current transducers the DEWETRON-designed power supply box can be used to connect up to eight current clamps or transducers. MSIs are also available for RTD type, LVDT, RVDT, IEPE, charge type sensors, thermocouple sensors, full-bridge, half-bridge, quarter-bridge strain gauges and more.

MSI2-V-600                                            

                                                            

When an MSI is connected to the PU[REC], the OXYGEN software will automatically recognize what type of sensor is connected to this channel thanks to the integrated TEDS (transducer electronic data sheet) chip.