Convert PSI Pressure Output to Level Output in Feet

The Seametrics PT-12 Submersible Pressure Sensor records the pressure exerted on its internal diaphragm from the surrounding environment and can convert this signal into a level measurement. The X2 data logger script has a built-in conversion factor that outputs the data in both pressure (PSI) and level (ft.) However, for the iSIC and iSIC-V2 data logger, a command must be sent within iChart to input this conversion factor and output level data, in feet, instead of the pressure data in PSI.


SDI-12 Commands

  1. Open iChart
  2. Go to Advanced | iSIC | iSIC to connect to the data logger.

iChart iSIC connection interface (Advanced | iSIC | iSIC).



  1. Click the SDI-12 tab.

iSIC Setup SDI-12 tab



  1. Send ?! to ensure the sensor is connected and can communicate through SDI-12.
    • An acknowledgment (ACK:) should display along with the sensor address.


  1. Input the following command to have the pressure output in PSI converted to level in feet and then click Send.
    • aXC16=2.31!
    • a corresponds to the SDI-12 address of the sensor, which can be found by following the previous step.

SDI-12 level conversion command for PT-12.



  1. Send the following command to set a level offset of zero.
    • aXC17=0.0!

SDI-12 level offset command for PT-12.



  1. Add the PT12 as a Generic|SDI-12 sensor in iChart with the attached settings and program the logger.
    1. Note: Match the SDI-12 address of your PT-12 in the smart sensor setup.


Using the generic SDI-12 option to add a PT-12 into an iChart project.