AVW200 OS 4
Updated: 18-11-2011

  1. The frequency measurement output has been improved to alert the user to low amplitude signal strength conditions. If the RMS signal strength is measured to be less than 0.01mV (10 microvolts) then NAN (or -9,999,999 for SDI-12 measurements) will be returned for the frequency reading. Signal strengths in this low range indicate problems with the deployed measurement configuration.
  2. Improved the measurement sequence to check for valid voltage supplies in the hardware of the device. If an internal calibration factor is outside of the expected range, then the value of -555,555 is returned for the frequency measurement. This indicates to the user that there is a hardware issue on the device which requires a factory examination and/or repair.
  3. New functionality has been added so that the AVW200 series device can control multiplexers via SDI-12 commands. This allows multiplexers to be connected directly to the AVW200 for SDI-12 measurement scenarios instead of being connected to the Datalogger or other controller. SDI-12 extended commands are used to set the absolute channel address of the multiplexer. The commands are aXMUXaa,ttt! or aXCMUXaa,ttt! (CRC check), where aa is the channel address and ttt is a timeout for how long the multiplexer will remain on and hold the address specified. An address of zero or timeout of zero will reset the multiplexer and zero any previous timeout setting. The timeout can also be updated by sending a new aX! command and selecting a new channel and timeout. In this way, a zero in-between commands isn't required.

  4. The SDI-12 aI! command result has been enhanced to return "AVW2xx" as the 6 character Sensor Model, and also to give the Version of the currently loaded firmware followed by an equals sign and the device's serial number in the 13 character Serial Number field. The 8 character Vendor ID shows as "Campbell".