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Wednesday, January 22, 2014

How to Check RTD Resistance on Nordson Cordset




If your Nordson unit is displaying a fault for the RTD and you have already verified all connections are secure, follow these steps to check the RTD Sensor:

Checking the RTD Sensor:  ALWAYS WEAR PROPER SAFETY GEAR

First, find out the temperature of the RTD to perform this check properly.
  • ·     Disconnect and lock out electrical power to the system.
  • ·        For the RTD being checked, disconnect the cordset that supplies power to RTD.
  • ·        Refer to Figure 11-7 or 11-8 as appropriate.  With the RTD at a know temperature, us an ohmmeter to measure the RTD resistance at the RTD pins at the cordset connector.
  • ·        Refer to Figure 11-9 to determine the correct resistance for the RTD base on its temperature.
    • o   If measured resistance is correct, the RTD is operating properly.
    • o   If measured resistance indicates an open circuit, continue to the next step.
  • ·        Remove the cordset connector hood and check for loose RTD wires or wire connections.  Tighten any loose connections.
  • ·        Check the RTD resistance again.  If the resistance is correct, the RTD is operating properly.  If resistance indicates an open circuit, continue to next step.
  • ·        Disconnect the RTD wire, measure the resistance across the wires and compare the results to Figure 11-9:

o   If measured resistance is within appropriate range, reconnect the RTD wires, reinstall the cordset connector hood and recheck the resistance at the RTD pins on connector.
o   If measured resistance is not within the appropriate range, replace the RTD.