DESCRIPTION
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. |
