Accessing serial commands from Modbus or analog mode - GMP252

GMP252 User Guide

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  1. Connect the USB cable to your PC and start the terminal application as instructed in Connecting with a computer.
  2. Start a new terminal session using the default serial settings.
  3. Keep the Enter key pressed down and connect the probe to the USB cable.
    When the probe is powered on (connected to your PC with the USB cable), you must send five carriage returns (Enter key presses) within 0.7 seconds to force the probe to serial command mode.
    The probe model information appears in the terminal application when the mode has been successfully changed, and Vaisala Industrial Protocol commands are available for use.
  4. To test the connection, enter for example the ? command. If the mode change failed, close the terminal application, disconnect the probe from the USB cable, and repeat 2 and 3.
  5. To keep the serial mode in use (forced serial mode access is temporary and switches off at reset), select a serial output option (stop/run/poll) with the smode command.
    Note that the probe always remains in analog mode when pin #5 is connected to pin #3, and cannot be switched to digital output in this wiring option.