This error message indicates that the signal from your sensor is absent. This may be caused by a faulty sensor, a break in the wiring from the sensor to the instrument, or a loose connection on the rear terminals. The 3 digit display as used on the model 6500 will show [OPN].
This message can also be generated if the input is incorrectly wired, or the input code and/or jumper are not correctly set for the type of signal applied.
Check the following sections in your product manual to correct these conditions:
Connections and Wiring
Internal Links and Switches
Configuration Mode - Input Code
It is possible to verify if the problem is located in the sensor or external wiring by following the procedures below:
Thermocouple Inputs
Turn off the power to the instrument
Disconnect the probe from the rear of the instrument.
Connect a small piece of wire (a paper clip will suffice)across the thermocouple input terminals.
Restore power to the instrument, which should display approximately ambient temperature if it is setup and working correctly.
RTD (PT100) Inputs
Turn off the power to the instrument
Disconnect the probe from the rear of the instrument.
Connect a 110 ohm resistor across the PT100 input terminals and a link to replace the third wire.
Restore power to the instrument, which should display approximately 20 to 30
