9.) THERMOCOUPLE
A thermocouple is used to measure the voltage that is generated as the
temperature increases. It provides an input signal for the control system that
monitors the temperature of the heated chamber.
At high temperatures, the elements within the thermocouple may undergo
some oxidation or corrosion causing the signals to be read incorrectly by the
control system.
To monitor temperature, If possible, the tip of the thermocouple must be
inside the heated chamber at least 1/8 deep. Also, the thermocouple tip must not
be blocked or shielded by items being heat treated.
If the control system indicates that a thermocouple is no longer
functioning, it is important to replace the malfunctioning thermocouple with the
same type model thermocouple that was originally provided with the furnace.
Replacement extension wires and connectors must also be compatible with the
thermocouple and the controller. If your system has a Eurotherm controller a
failed thermocouple will be indicated by SBR on the display and for a Yokogawa
controller it will indicate B.OUT. Refer to the replacement parts list to determine
the type of thermocouple required.
For optimal performance the thermocouple should be replaced one a year.
In some cases a more frequent replacement schedule may be required.
NOTE: Polarity of the thermocouple extension wires is the
OPPOSITE of the polarity of typical electrical wiring. The red leg is always
negative for thermocouples while the black leg is always positive.
Summary of Contents for XST-2-0-12-1V1-E28
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