Sense mode

Avatar of admin admin - 25. May 2021 - Option

In the different branches like industry, research, automotive, railway, aerospace, automation and system integration there are many applications where the required laboratory power supply has to be connected to the application via a longer cable. From a technical point of view, this leads to a voltage drop via the power resistor and the voltage applied to the consumer is therefore lower than the output voltage set at the DC source.

Load connection without sensor cable

Our laboratory power supplies of the LAB/SMP, LAB/SMP/E and LAB/HP series have sensing lead connections for readjusting the output voltage in order to compensate for the voltage drop on the load lines. If these are not used, they must always be short-circuited with the correct polarity to the load outputs directly at the output terminals. Under no conditions may current flow through the sensor connections. If there are several consumers, a central load distribution point must be provided. A capacitor 1-10 µF should be connected to the output to reduce load peaks and to terminate the HF impedance.

 

 

Load connection with sensor cable

If the existing sensor lines are connected directly to the load or to the central load distribution point, the following points must be observed:

  • Remove existing sensor cable bridges at the power supply unit.
  • Connect + Sense and - Sense with correct polarity directly to the load distribution point.
  • Terminate the + sense and - sense lines with a 1-47 µF capacitor.
  • Shield the sensor cable, if no shielding is possible, at least run + Sense and - Sense in twisted pairs.
  • Select load line cross-section so that voltage drop < 0.4 VSelect load line cross-section so that voltage drop < 0.4 V
  • Avoid overloading the power supply units (voltage drop per line x current)

 

Technical information on the Sense function

The sense wire transfers the measuring point of the output voltage measurement to the load. The voltage measurement is carried out with a differential amplifier, with the last resistor in the chain being "short-circuited" with a low-resistance parallel resistor. When the sense line is opened, the output voltage increases between 1% and 2% of the nominal voltage, according to the model. The voltage shown on the display does not change. When the sense is connected to the load, the power resistance is converted mathematically into the unit; a residual error of up to 0.5% may occur depending on the load line used. More detailed information can be obtained from the manufacturer.

 

 

 

 

 

 

 

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