Rosemount 248 - Rtds; Thermowells

Reference Manual
00809-0100-4825, Rev BB
August 2005
A-7
Rosemount 248
RTDs Sensor Type
100 ohm RTD at 0 °C, α = 0.00385 ohms/ohm/°C.
Accuracy
Meets IEC 751 Class B tolerances
Temperature Range
–50 to 450 °C (–58 to 842 °F)
Self Heating
0.15 °K/mW when measured per method defined in DIN EN 60751:1996 or 16
mW minimum power dissipation required to cause a 1 °C (1.8 °F) temperature
measurement error in water flowing at 0.91 m/s (3 ft/s)
Thermal Response Time
9 seconds maximum required to reach 50% sensor response when tested in
flowing water according to IEC 751 or 12 seconds maximum required to reach
63.2% sensor response in water flowing at 0.91 m/s (3 ft/s).
Immersion Error
60 mm minimum usable depth of immersion when tested according to IEC
751.
Insulation Resistance
500 megaohms minimum insulation resistance when measured at 500 V dc at
room temperature.
Sheath Material
321 SST with mineral-insulated cable construction.
Lead Wires
PTFE insulated, coated 22 gauge stranded copper wire.
Thermowells Materials
Barstock Thermowells: 316L SST (1.4404)
Tubular Thermowells: 1.4571 (316 Ti)
Construction
Thermowell bodies are either machined from solid barstock or manufactured
using swaged tubes. Flange mounts are seal welded to the thermowell body
with the exception of Class 900 flanges and above, which are full penetration
welded. Surface finish of machined stems is 0.8 μm (32 μ in. CLA.N6).
Material certification (option code Q8) and pressure testing (option code R01)
are available. Flanged thermowells generally conform to the specifications of
ASME B 16.5 (ANSI), DIN 2519, 2527, 2633, 2635, and DIN 2526 Type C
Other thermowell materials and styles are available in Volume 1, 2, and 3 of
the Temperature Sensor and Accessories Product Data Sheet.