8
Digital Thermometer Model K2000F and Temperature Probe Model ST2-2000
6. SENSORS AND PROBE EXTENSIONS
General Notes
ISOLATION
The thermocouple is incorporated into the extreme tip of each of the sen-
sors described in this booklet. The thermocouple is solid with the body of
the sensor.
SENSOR RESPONSE TIME
The response time of a thermocouple is the time taken for it to settle to a
new value after the introduction of a temperature step. For a thermocouple
plugged into a medium having a high calorific value, good thermal conduc-
tivity and good thermal contact, the response time should be extremely
short (intrinsic response time). If the thermal medium is unfavorable (e.g.
calm air) the actual response time could attain 100 times or more of the
thermocouple itself. Values for the K2000F and ST2-2000 sensors have
been established under the following conditions:
• For supple and auto-grip surface sensors in contact with a polished
stainless steel plate coated with silicon grease.
• For the air sensor, in agitated air (1 m/s).
• For the other sensors, by immersion in agitated water at 194°F (90°C)
(agitation speed: 0.3 to 0.5 m/s).
TEMPERATURE RANGE
The temperature range for each sensor is given for use in chemically neu-
tral environments. The introduction of a sensor into a corrosive medium
could shorten its life or limit recommended working range.
SENSOR CLASSIFICATIONS
K type thermocouple sensors are either Class I or II (according to stan-
dard NF C 43-322). Class I is denominated reduced tolerance and Class
II standard tolerance.
CLASS I
± 3°F (1.5°C)
± 0.4% reading
CLASS II
± 5°F (2.5°C)
± 0.75% reading
-40°F 32°F
626°F 707°F
1652°F
