Keithley 7402

This Thermocouple Scanner Card is field installable in the Model 740 scanning thermometer and the Models 705 and 706 scanner mainframes.

Since it combines the functions of a thermocouple scanner and a uniform temperature reference, it is especially useful for scanning thermocouples.

The input terminals are set in an isothermal block to minimize temperature differences.

An integrated circuit temperature transducer within the isothermal block senses the reference (cold) junction temperature and converts it to a proportional current.

The temperature of the heat sink is used to calculate the corrected thermocouple output.

The output voltages of eack thermocouple must be converted to temperature (°C or °F) using appropriate thermocouple tables or polynomial equations.