Communicating With Watson Sensors

Most Watson Industries digital sensors have settings that are saved in memory. These settings include things like data channels and baud rate that user might find the need to change from time to time. In order to access the menu system to change these settings, the sensor needs to be in Command Mode. There are a series of steps that need to be performed to put the sensor into this special mode.

  1. Connect the unit to a DC power source that is off.
  2. The viewing computer needs a valid bi-directional RS-232 serial port. Connect the serial port of the Watson sensor to the computer’s serial port.
  3. Open a terminal program (such as HyperTerminal) to interface with the unit. The default baud rate of Watson sensors is 9600 baud. Make sure the computer’s serial port is set to the appropriate baud rate and that the port is open.
  4. Power-on the sensor. By default, a startup message will be transmitted by the Watson unit and will appear in the terminal window. This is the start of the “sensor initialization” phase.
  5. During sensor initialization, press the spacebar twice in close succession.
    Note: The sensor initialization phase begins after the startup message is transmitted. Typically, this time period lasts about 5 seconds, but could be as long as 127 seconds – depending on your particular sensor.
  6. Wait until after the initialization phase is finished. After this phase, Command Mode will be activated and the unit will accept keyboard commands.
    Note: Most Watson sensors have initialization times that are shorter than 30 seconds. Any extra keystrokes (other than two spacebars) sent during initialization will deactivate command mode.

It can often take a few attempts to get familiar with performing step 5. Repeat steps 4-6 until successful.