Dewe-43 Analogue input power supply outputs

nick arran

Posted on 25.08.2022 11:00

Can someone please explain to me the differences between: Exc+ (pin 1) Sense+ (pin 6) and 12V (pin 5).

I have a position sensor that needs a +12V and 0V supply and which returns 3V or 12V (wrt to the 0V supply) when it detects an object. But which of the pins should I use to make that 12V power supply?

Rok Kmetič
Customer Support Engineer
Posted on 25.08.2022 15:12

Dear Nick,

  1. The EXC lines provide +/-5 V and 70 mA per channel.
  2. Our EXC accuracy is specified with SNS lines correctly connected to the EXC lines at the point of load. Sense amplifier is a vital and important part of the EXC voltage regulation. It forms a feedback loop for correct EXC voltage regulation. These lines allow the DAQ to measure the excitation voltage very accurately through a high-impedance circuit that is not carrying any current and then adjust the excitation to compensate for any line loss and resistance change due to temperature fluctuations, further increasing the signal accuracy.

    Note that in all of our schematics and manuals we try to be as clear as possible that SNS and EXC shall be connected at all times.
  3. 12V (pin 5) This is a sensor supply providing 350 mA (Shared between 8xAI, 8xCounters, 2xCAN)

For a visual explanation of how the power is transferred inside the device please see the picture below:

To connect your sensor I would recommend using this connection diagram:

If you require any further information, feel free to contact me.

Best regards.

Rok Kmetič

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