The function of this reference unit differs from other cased systems in that the temperature of the metal
block in which the thermocouple and copper leads are inserted, actually varies with ambient temperature.
A separate output signal is produced which is proportional to the difference between the environmental
temperature and the actual reference temperature. The output signal can be fed directly into a
computer/data logger to give accurate compensation over a large ambient range.
A thermal reservoir, heavily insulated, contains the reference junction probes. The reservoir temperature
slowly follows the ambient temperature; an electrical compensation device is thermally integrated with the
reservoir and thus senses the reservoir temperature. The device produces an output proportional to the
difference between the reservoir temperature and the reference temperature (usually 0°C).
This is the signal the computer/data logger uses to compensate for the temperature of the reference
probes junctions.
Units are housed in robust weatherproof enclosures to IP669 incorporating bottom gland plate. Fixing lugs
for wall mounting are provided. Easy access to terminal rails and block assembly is via a lockable hinged
front door. |