This unit is physically identical to the general purpose Model 418 except that the vernier in-out switch is replaced with a switch which turns the internal reference junction circuits on and off. With this switch off, the Model T418 accepts conventional millivolt input signals.
When the internal reference circuits are activated, the Model T418 indirectly performs the function of thermocouple reference junction compensation. The physical reference junction occurs on a model Model 683 Universal Thermocouple Adapter. This adapter screws into the input connectors at the rear of the appropriate 400 Series mounting enclosure. It contains a temperature sensitive element which is connected into the Model T418 through the enclosure wiring. This sensing device combines with the T418 circuits to provide stable reference junction compensation.
The proper enclosure for the Model T418 is the Model R408-14. This enclosure accepts up to 14 Model T418’s or 418’s in any combination. A Model 683 adapter must be procured for each thermocouple channel but mating connectors for non-thermocouple inputs are supplied with the enclosure. Any channel can be used for thermocouple, strain gage or millivolt inputs by simply choosing between the thermocouple adapter or the conventional mating connector.
- 100 g Shock
- 20 g Continuous Vibration
- 100% Relative Humidity
- Thermal Shock Resistant
- True Differential Amplifier
- 0.5 µV/°C stability
- Thermocouple Reference Junction