RTDs / Probe RTDs : Series 218 1/8” dia.

Series 218: 1/8” Industrial Platinum RTD Probes

RdF PNs: 218A, 218T

The Series 218, with its 1/8" diameter sheath further supplements the versatile Series 21 RTDs which have a probe diameter of 1/4". The 1/8" diameter offers the advantage of faster response while the strain-free construction, high accuracy and stability offer long-term reliability.

The Series 218 RTDs are versatile and can be used in many different applications. They are offered with premium strain-free wire-wound sensing elements in Reference and International grade platinum having 100 and 200 ohm resistance values with tolerances of ±0.1%. Extra-tight tolerances are available. They are also offered in IEC 751/DIN International Grade B Thin Film Elements. The probes are available in 2, 3, and 4 wire configurations with Teflon® or optional fiberglass insulation.

All Series 218 probes can be used with adjustable compression fittings.

TYPE “A”

TYPE “T”

Performance Specifications

   
 

Operating Temperature Range
–196°C to 480°C (–320°F to 900°F)

Maximum Operating Temperature
900°F over tip end length.
Note: If lead exit temperature will exceed 260°C (500°F), please specify on order.

Resistance
See Ordering Specifications Table.
Lead wire resistance to the element is not included for the
2-wire configuration.
The 3-wire and 4-wire units allow compensation for lead wire resistance.

Temperature Coefficients of Resistance:
0.003924 Ω/Ω/°C (Reference)
0.003850 Ω/Ω/°C (IEC/DIN)

Accuracy
±0.25°C @ 0°C (32°F)
±0.3°C @ 0°C (32°F)
on IEC/DIN thin films

      

Stability
Less than 0.05°C shift per year full span on wire elements.
–50°C to 300°C (–60°F to 500°F) span on thin films

Self-Heating
75 mW/°F in water flowing at 3 ft. per sec.

Pressure Rating
3000 PSI at welded header boundary

Insulation Resistance
500 Megohms minimum @100 VDC at room temperature

Time Constant
Less than 2 sec, in water flowing at 3 ft. per sec.

Standard Leads
22 AWG stranded, nickel plated copper, Teflon® insulated, except 3-wire leads
on type “A” are 28 AWG.
3 or 4-wire leads over 36" are cabled on type “T”.
Type “A” 3-wire leads over 36" are not cabled unless designated for operation below 500°F.

 
   

Ordering Specifications


 TYPE  1/8" diameter Platinum RTD Probes (316 stainless steel)
 218A   Straight Sheath
 218T   Striaght Sheath with 1" long x 1/4" Diameter Transition
 RTD RESISTANCE SPECIFICATION (ohms @ O°C)
   10      100    ±0.1Ω   Strain Free wire-wound 0.003924 Ω/Ω/°C (RdF Reference Grade)
   11      100    ±0.1Ω    Strain Free wire-wound 0.00385 Ω/Ω/°C (IEC/DIN)
   20      200    ±0.2Ω    Strain Free wire-wound 0.003924 Ω/Ω/°C (RdF Reference Grade)
   21      200    ±0.2Ω    Strain Free wire-wound 0.00385 Ω/Ω/°C (IEC/DIN)
   T01    100    ±0.12Ω  Thin Film 0.00385 Ω/Ω/°C (IEC/DIN Grade B)
   T05    500    ±0.6Ω    Thin Film 0.00385 Ω/Ω/°C (IEC/DIN Grade B)
   T10    1000  ±1.2Ω    Thin Film 0.00385 Ω/Ω/°C (IEC/DIN Grade B)
 *PROBE LENGTH
  Specify "L" in inches(3" minimum on wire-wound only; 1" on thin films)
 NUMBER OF LEADS
      A  single element,2 wires any length
      B  single element,3 wires 36" or under in length
      C  single element,4 wires 36" or under in length(Not available on type "A")
      X3  single element,3 wire cable over 36"(on Type"A", only for operation below 500°F
      X4  single element, 4 wire cable over 36"(Not available on Type "A")
 LEAD Length - Inches(6" standard)
218A
10
6
A
24
 Typical write-up for 218A

Adjustable Compression Fitting

Part
No		 Process
Mounting		 Material Sensor Sheath
Diameter
51841-1 1/8 NPT Stainless Steel 0.125
51841-2 1/4 NPT Stainless Steel 0.125
51841-3 1/4 NPT Stainless Steel 0.25(transition)
51841-4 1/2 NPT Stainless Steel 0.25(transition)