February/March 2021

INDUSTRY NEWS 19 www.power-mag.com Issue 1 2021 Power Electronics Europe channels can be provided. The dual capture feature offers both data acquisition recorder functionality and the sample speed and trigger features of an oscilloscope. This allows developers to analyze the finest waveform details while observing multi-channel measurements over longer periods. Five options for acquiring data, allowing users to choose the best method for their application are offered. They can opt for normal acquisition into the fast internal acquisition memory, recording to flash memory (coming soon), recording to the internal hard disk (SSD) or directly to the PC via normal Ethernet or opt for 10 Gigabit Ethernet. Data can be captured to a PC streaming over a very long time at up to 160 MB/s, with data volumes limited only by the PC’s storage. Using 10 Gigabit Ethernet, data can be transferred from the DL950 to a PC at 50 times the speed of its predecessor. A fiber optic cord and the Yokogawa’s IS8000 PC software are used for transmission. The DL950 will also feature Flash Acquisition (coming soon), used to store data when a PC cannot be used, for example when capturing data from within a vehicle, power plant or other similar applications. In this case data can be captured over a long time with a high-speed sample rate of 20 MS/s (8 CH) and 10 MS/s (16 CH). The 512 GB internal SSD can record up to 50 days. Depending on the sample rate it can record for five hours on one channel at up to 2 MS/s, or record at 200 kS/s for 20 hours with 16 channels. Waveforms from dual capture can also be recorded, useful for in-vehicle endurance testing and capturing rare spontaneous events. 21 types of input modules are available, including 12-, 14- and 16-bit isolation modules, universal voltage/temperature modules, acceleration/voltage modules, strain modules and frequency modules. Up to five DL950s can be synchronized to allow the use of up to 160 voltage channels. Alternatively, up to 640 temperature channels can be used, employing 16 channels with eight slots for each of five DL950 units. The subunits can be synchronized to start and stop their measurements via signals from the main unit. Following a few typical applications where the DL950 can be used. Application SMPS output monitoring There are many tests needed for SMPS design such as power quality, inrush current, and MOSFET switching testing (Figure 2). One of the key tests is to monitor and record the SMPS output current characteristics when connected to different loads at a high sampling rate for a long period of time. Any change in output current due to the dynamic load conditions is monitored and saved for further analysis. To perform this test, engineers need an instrument that can meet the requirements of SMPS output voltage and current measurement, isolated input channels, high A/D resolution, high speed data sampling rate, long period of recording time (a few minutes to an hour), and data storage. For this application the 200MS/s, 2-channel- 14 bit isolated module 720212 is available. It offers a bandwidth from DC to 40 MHz ans an input voltage of 1000 V(DC+ACpeak). The 4CH 10 MS/s 16-bit isolated module 720256 offers a bandwidth from DC to 3 MHz at 600 V (DC+ACpeak). Here the DL950 can be used as a normal oscilloscope to conduct other tests such as power quality, inrush current, and MOSFET switching testing (amplitude, duty cycle, frequency). Also, it can be used as a recorder by switching oscilloscope/recorder mode. Users can use the DL950 in a measuring instrument mode they are familiar with. Electric power steering Electric Power Steering (EPS) uses an electric motor rather than hydraulic pressure to assist in automobile steering (Figure 3). As the use of electronic control systems for the entire vehicle progresses, EPS systems have been introduced, resulting in lighter weight compared to hydraulic systems, which improves fuel efficiency and provides greater control flexibility by changing the steering force for each vehicle speed. In addition to EPS, this technology improves vehicle stability by cooperating control of brakes and throttle, and supports tandem parking and garage parking by cooperating with Intelligent Parking Assist (IPA). To evaluate an EPS steering subsystem, it is necessary to continuously record and analyze the steering angle, various sensor outputs, ECU inputs and outputs, etc. in an integrated manner. The DL950 ScopeCorder provides the measurement capabilities required by Figure 2: In SMPS testing the DL950 can be used as a normal oscilloscope to conduct other tests such as power quality, inrush current, and MOSFET switching testing Figure 3: In power steering application the DL950 can simultaneously record voltage, current, and CAN data Yokogawa-EPS.JPG