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Water Level

Water Flow

Water Samplers

Water Quality


Remote Monitoring

Industrial Control



     No communication from the GL300A/B 

  1. Check that the proper baud rate and COM port are selected in the LS-4 settings menu.  When the logger is configured for modem operation the baud rate will either be set at 1200 or 2400 baud.  The baud rate setting in the logger will be shown by a label next to the DB-9 connector.  The default baud rate in the LS-4 software is 4800.
  2. Ensure that a CC-6 communication cable or an equivalent cable is being used for communications.
  3. Check the voltage of the 9-volt lithium battery using a voltmeter.  This battery should be greater than 8 volts.  If the voltage of this battery is less than 8 volts it should be replaced.
  4. If the status LED is on bright continuously the logger may be locked up due to hardware failure or contact with a static charge.  The logger can often be brought out of this lock up state by doing a power reset.  This can be done by removing both the 9-volt lithium battery and the 12-volt Gel-Cell  for approximately 20 seconds and then reconnecting them.  After this is done try communicating with the logger, again checking all of the logger's functions.  The logger's memory will be maintained by the on-board 3-volt lithium battery.
  5. At this point it is a good idea to see if any other devices are in conflict with the port.  In some lap top computers the COM port is disabled unless Windows 3.1 or 95 is active.
  6. Disconnect any sensors that are connected to the logger.  A defective sensor could cause the logger to lock-up.
  7. Ensure that the Communication Time Out in the Settings menu is greater than the sensors warm-up time.
  8. There are a few computers that have trouble communicating with the GL300A/B. This is due to incompatible RS - 232 levels.  With these computers, the status LED will flash momentarily, but will otherwise remain dim when trying to communicate.  These computers require a UCB COM Buffer Module when trying to communicate with the logger.  The UCB COM Buffer connects to the computer end of the communication cable, converting the RS - 232signal of the computer to proper levels for the logger.
      Sensor is not reading correctly
  1. Check that the correct Format is active when translating data or viewing it in the Monitor Mode.
  2. Check the condition of the datalogger batteries (main & auxiliary).
  3. Check the sensor cable and connections on the terminal strip.
  4. When using excitation from the logger ensure that the sensor has a long enough warm-up time.  Turn the Auxiliary on continuously by selecting Aux.  Turn-on and check the sensor's readings in the Monitor mode.
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