the hermetic cell, thus the reference well and installed thermocouples, or other sensor, are
continuously surrounded by an equilibrium ice-water mixture.
d. INSTRUMENT BLOCK DIAGRAM (See figure 15).
e. OPERATING INSTRUCTIONS
(1) LINE SOURCE. Plug line cord into any 115 V, 60 cycle, grounded outlet.
(2) SWITCH. Turn the "ON/OFF" switch on the front of the reference unit to
"ON". The pilot light should come on at this time.
(3) PULL-DOWN. Approximately 45 minutes after the unit has been turned on,
the reference unit will start to cycle. This cycling will be indicated by the pilot
light which will be alternately "On" and "off". (The pilot light is operated in
parallel with the thermoelectric cooling module and, hence, indicates when the
cell is being cooled).
(4) STABILIZATION. Once the pilot light has started to cycle, allow 10 to 15
minutes for the cell to stabilize. Your instrument is now ready for operation.
(a) Temperature form 22, C. to 24, C.
(5) USAGE. The unit is now ready for calibration use. When thermometers,
thermocouples or resistance sensors are inserted into the reference well, the
following steps must be observed in order to obtain accurate and repeatable
(a) Depth. All sensors must be inserted completely to the bottom of the
well. If a sensor is stepped such that full well depth immersion is
impossible, accuracy and repeatability of results must be evaluated, based
on the users own experiments.