LTT24 real time measuring system

Electric drives are conquering our daily lives: cordless screwdrivers, angle grinders, electric bikes and electric cars must function with maximum efficiency over the greatest possible load ranges.

Test standards, such as DIN IEC 60034-2-3, define the test requirements for determining the efficiency of such inverter-fed drives.

The underlying chopped square wave voltage and the associated current must lead to correct phases and amplitudes and a performance statement with a maximum error tolerance of 0.3%. In order to achieve this accuracy of 0.3%, the theoretical frequency consideration of a square wave voltage means that all frequencies up to the 19th Harmonic of the switching frequency of the inverter must be taken into consideration. At a switching frequency of 10-20 kHz this is a signal bandwidth of 0-380 kHz in which the signal fidelity of all components must be better than 0.3%. This requires a measurement technology with a continuous sampling rate of 2-4MHz without distorting filters.

Particularly in high-performance automotive electric motors, increasingly high battery voltages with currently up to 800 V are used. At a bandwidth of 380 kHz, a pulsed 800 V signal shape becomes a real challenge. The challenge is to build the high-voltage divider in such a way that its total measurement error is guaranteed to remain below 0.3% over the entire frequency, voltage and temperature ranges despite the fact the non-linearities of all electronic components already have a massive impact here. At the same time, the pulsating current of this 800 V pulsating inverter voltage must be measured. That is a real challenge for the galvanic isolation of the current input.

The LTT24 is the only device worldwide that successfully combines the required bandwidth and accuracy. No other power meter can meet the signal accuracies required by the standards in terms of voltage AND frequency. Other devices fail to achieve either the required accuracy or the required bandwidth. The LTT24 is the only solution you can rely on to support your test bench design. The sky is the limit!

Technical specifications

Modular housing

• Housing size: 4, 8, 16
  
• also suitable for 19" installations
  
• Number of channels from 1 to 16 and more
  
• Expandable at any time
  
• configurable functionality
  

Modular channels

• Ultra performance: 24 bits technology with 4 M sample/s per channel
  
• Best accuracy on the market: 16 ENOB
  
• Best flat bandwidth on the market: DC – 1.7 MHz
  
• Best interference suppression (CMRR) on the market
  
• Best galvanic isolation: No-Noise DC/DC supply with 2 MHz clock pulse
  
• Suitable sensor supply: Voltage, current, carrier frequency
  
• Signal inputs for: volt, current, charge, ICP®, strain gage, current, LVDT,
  
• resistance etc. with corresponding sensor supply
  
• Slow channels: 24 bits with 2 k sample/s for e.g. temperature, pressures, etc.
  
• Analog outputs up to 2 MHz and 16 bits resolution
  
• Digital channels: SPI, pulse etc.
  

Modular options

• 1 - 32 analog outputs
  
• 1 - 256 digital IOs
  
• Internal Recording: internal SSD hard disk (500 GB)
  - Don't ever miss anything important again, just rewind!
  

Connection options

• Digital I/O and Syc.-Interface for external hardware
  
• SyncE and IEEE1588: Nano-second synchronization via Gigabit Ethernet
  
• USB 3.0 and Dual Gigabit Ethernet connection to PC
  

Data transfer rate

• SSD 256 Mbytes
  
• PC via USB 170 Mbytes
  
• PC via Gigabit interface 127 Mbytes
  

We are pleased to support you:
SL-automation GmbH & Co. KG

Telephone: +49 (0) 731 98588-790
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