DATA SHEET R-21
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_

STRAIGHT PROBE ASSEMBLIES
TYPE 21A

Features: 1/4" dia. 316 SS sheath; operating range –320°F to 900°F, Teflon® insulated lead wires; single or dual elements, RdF Reference or IEC/DIN R vs. T characteristics, and 2, 3 or 4 wire element configurations.

RIGID PROBE ASSEMBLIES WITH
HERMETICALLY SEALED CONNECTOR
TYPE 21C

Features: 1/4" dia. 316 SS sheath with hermetically sealed 4-pin connector; operating range –320°F to 900°F single or dual elements; RdF Reference or IEC/DIN R vs. T characteristics, and 2, 3 or 4 wire configurations.
*P/N 53105 (Mating Connector) must be ordered seperately.

HERMETICALLY SEALED
PROBE ASSEMBLIES
TYPE 21H

Features: 1/4" dia. SS sheath; operating range –320°F
to 900°F; Teflon® insulated 3-conductor cable; RdF Reference or IEC/DIN R vs. T characteristics. Integral hermetic seal. Single element only.

  
 21A/C/H
  RTD RESISTANCE SPECIFICATIONS (Ohms @ 0°C)
  10    100 ± 0.1 (a = 0.003924 Ω/Ω/°C) RdF Ref. Std.
  11    100 ± 0.1 (a = 0.00385 Ω/Ω/°C) IEC/DIN Std.
  T01   100 + 0.12 (a = 0.00385 Ω/Ω/°C) thin film
  20    200 ± 0.2 (a = 0.003924 Ω/Ω/°C)
  21    200 ± 0.2 (a = 0.00385 Ω/Ω/°C)
  T05   500 ± 0.6 (a = 0.00385 Ω/Ω/°C) thin film
  T10   1000 ± 1.2 (a = 0.00385 Ω/Ω/°C) thin film
  102*  100 ± 0.1 Dual Element (a = 0.003924 Ω/Ω/°C)
  112*  100 ± 0.1 Dual Element (a = 0.00385 Ω/Ω/°C)
  T012* 100 ± 0.12 Dual Element (a = 0.00385 Ω/Ω/°C) thin film
       *Not Available on 21H
 SERVICE PARAMETER – Sinusoidal Vibration 20Hz to 2kHz
  S  Standard construction (25 g wire-wound, 80 g thin film)
  H  Heavy-duty construction (up to 50 g)
     (1 wire element only)
 PROBE LENGTH (Specify “L” in inches) 
      Std. Const: 3" minimum,
      Heavy Duly: 3" minimum for 21H,
      4" minimum for 21A & 21C (see photos)
 LEAD WIRE CONFIGURATION
A Single element, 2 wires, any length
B* Single element, 3 wires,
(36" or under on 21A),
*21H requires B cable, any length,
standard.
C Single element, 4 wires,
(36" or under on 21A)
D Dual element, 2 wires per element
E Dual element, 3 wires per element,
21A only
 ARMOR LENGTH (21A only)
     Specify “X” in inches (ie. A0= no armor,
     A60 = 60 inches) (Single element only)
 LEAD LENGTH - Specify in inches
     (Not applicable to 21C)
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21A
_
_
_
10
_
_
_
S
_
_
_
4
_
_
_
B
_
_
_
A60
_
_
_
60
_
_
_  Typical write-up for 21A
21B
_
_
_
T10
_
_
_
A
_
_
_
8
_
_
_
A
_
_
_
-
_
_
_
60
_
_
_  Typical write-up for 21C
 

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RIGID PROBE ASSEMBLIES
WITH HEX FITTING
TYPE 21B

Features: 1/4" dia. 316 SS sheath and threaded fitting for connection head assembly; operating range –320°F to 900°F; Teflon® insulated lead wires; single or dual elements; RdF Reference or IEC/DIN R vs. T characteristics, and 2, 3 or 4 wire element configurations.
_
21B 14" Diameter Sheathed Platinum Probe, Rigid Mount to Fitting _
_  
     RTD RESISTANCE SPECIFICATIONS (Ohms @ 0°C) _
10
11
T01
20
21
T05
T10
102
112
T012		 100 ± 0.1 (a = 0.003924 Ω/Ω/°C) RdF Ref. Std.
100 ± 0.1 (a = 0.00385 Ω/Ω/°C) IEC/DIN Std.
100 ± 0.12 (a = 0.00385 Ω/Ω/°C) thin film
200 ± 0.2 (a = 0.003924 Ω/Ω/°C)
200 ± 0.2 (a = 0.00385 Ω/Ω/°C)
500 ± 0.6 (a = 0.00385 Ω/Ω/°C) thin film
1000 ± 1.2 (a = 0.00385 Ω/Ω/°C) thin film
100 ± 0.1 Dual element (a = 0.003924 Ω/Ω/°C)
100 ± 0.1 Dual element (a = 0.00385 Ω/Ω/°C)
100 ± 0.12 Dual element (a = 0.00385 Ω/Ω/°C) thin film
_  
_     CONNECTION HEAD (see connection head table below) _
_  
_     SERVICE PARAMETER - Sinusoidal Vibration 20Hz to 2kHz _
S
H		 Standard construction (25 g wire-wound, 80 g thin film)
Heavy duty construction (up to 50 g) (single wire element only)
_  
_     PROBE LENGTH _
_ (Specify “L” in inches, >60" requires support) (see photo)
Std. Const: 3" min, Heavy Duty: 4" min.
_ _
_     NUMBER OF LEADS _
A
B
C
D
E
X3
AX3
X4
AX4		 Single element, 2 wires any length
Single element, 3 wires 36" or under in length
Single element, 4 wires 36" or under in length
Dual element, 2 wires per element
Dual element, 3 wires per element
Single element, 3 wire cable over 36"
Adds stainless steel armor excluding last 5"
Single element , 4 wire cable over 36"
Adds stainless steel armor excluding last 5"
_ _
_     ARMOR LENGTH
           Specify “X” in inches (ie. A0= no armor,
           A60 = 60 inches) (Single element only)		 _
_ _
    LEAD LENGTH - Specify in inches (4" Standard)
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_ _
_ _
21B
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_
–
11
_
_
–
D
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_
–
S
_
_
–
6
_
_
–
B
_
_
–
A0
_
_
–
4
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_
–   Typical Write-up for 21B
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Connection Heads with Terminals
Nema 4 w/Gasket Illustrations on Data Sheet T-WELLS/ACCESSORIES
CODE _  to order with sensor:  to order alone:   Conduit Max. Temp
A  Small cast aluminum head  P/N 51590-1   1/2 NPT 125°C
B  High temp. small cast aluminum head  P/N 51590-2   1/2 NPT 260°C
C  Cast Iron head  P/N 51840-1   3/4 NPT 260°C
D  For no connection head specify “D”        
E  Large cast aluminum head  P/N 52298-1   3/4 NPT 260°C
F  Economy conduit body  P/N 41438   1/2 NPT 125°C
G  Explosion proof small cast aluminum head  P/N 41333-1   1/2 NPT 125°C
H  High temp. expl. proof small cast aluminum head  P/N 41333-2   1/2 NPT 260°C
I  Hinged plastic  P/N 54684   3/4 NPT 125°C
J  Hinged cast aluminum  P/N 54681   3/4 NPT 125°C
K  Din B cast aluminum  P/N 55261   1/2 NPT 100°C
S  Other (please specify when ordering)        
T  Transmitter, specify or supply w/head        
Terminals: All heads include at least 4 two-screw strap terminations. 6 can be requested in styles “C” and “E”. Style “K” includes 6 two-screw post straps. Styles “A”, “B”, “G” & “H” can have up to 8 screw-in post straps.
 

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SPRING LOADED PROBE ASSEMBLIES
WITH HEX FITTING
TYPE 21D

Features: 1/4" diameter 316 SS sheath; operating range
–320°F to 900°F with universal hardware for spring-
loading; single or dual elements; RdF Reference or
IEC/DIN R vs T characteristics, and 2, 3 or 4 wire element
configurations. Styles A & B Head Shown.


Thermowell not included—order separately; see data sheet T-WELLS 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
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_ 21D 1/4" Diameter Sheathed Platinum Probe, Spring-Loaded
_  
_      RTD RESISTANCE SPECIFICATIONS (Ohms @ 0°C)
10
11
T01
20
21
T05
T10
102
112
T012		 100 ± 0.1 (a = 0.003924 Ω/Ω/°C) RdF Ref. Std.
100 ± 0.1 (a = 0.00385 Ω/Ω/°C) IEC/DIN Std.
100 ± 0.12 (a = 0.00385 Ω/Ω/°C) thin film
200 ± 0.2 (a = 0.003924 Ω/Ω/°C)
200 ± 0.2 (a = 0.00385 Ω/Ω/°C)
500 ± 0.6 (a = 0.00385 Ω/Ω/°C) thin film
1000 ± 1.2 (a = 0.00385 Ω/Ω/°C) thin film
100 ± 0.1 Dual Element (a = 0.003924 Ω/Ω/°C)
100 ± 0.1 Dual Element (a = 0.00385 Ω/Ω/°C)
100 ± 0.12 Dual Element (a = 0.00385 Ω/Ω/°C) thin film
_  
_      SERVICE PARAMETER - Sinusoidal Vibration 20Hz to 2kHz
S
H		 Standard construction (25 g wire-wound, 80 g thin film)
Heavy duty construction (up to 50 g) (single wire element only)
_  
_ _ _     PROBE LENGTH IN THERMOWELL
  Std. Const: 2" min, Heavy Duty: 3" min (see photo)
Specify length "A" (bore depth) in inches
_  
_      PROBE LAG HARDWARE - 1/2 NPT Fittings, stainless steel unless noted.
A
BX
EX
FX
GX
HX
JX

KX		 Hex Nipple is 3/4" long standard. Specify as "A", (standard)
(Straight Nipple), specify X=1/8", 1/2", 1" + 1" increments
(Aluminum Union/Nipple Extension), specify X=min. 3" plus 1" increments
Same as EX (stainless union)
(Coupling/nipple extension), black iron, specify X=min. 3" + 1" increments
(Union/nipple extension), black iron, specify X=min. 3" + 1" increments
(Close nipple, galvanized unsealed parting coupling, nipple extension)
black iron, specify x=min. 1 1/2" + 1" increments (shortest “union”)
(Straight nipple) black iron, specify x=1/8", 1/2", 1", + 1" incr. (CREDIT)
_  
_      CONNECTION HEAD (see connection head table)
_  
_ _    NUMBER OF LEADS
A
B
C
D
E		 Single element, 2 wires any length
Single element, 3 wires 36" or under in length
Single element, 4 wires 36" or under in length
Dual element, 2 wires per element
Dual element, 3 wires per element
 
_      LEAD LENGTH (Specify in inches)
     (4" Standard)
_
_ _
_ _
21D
_
_
–
11
_
_
–
S
_
_
–
6
_
_
–
A
_
_
–
B
_
_
–
B
_
_
–
4
_
_
– Typical Write-Up for 21D
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LAG HARDWARE REFERENCE     
     
 

Features
Premium RTD Probe Assemblies with strain free
wire-wound sensing elements or economical
thin film sensing elements.
Operating Temperature Range
–196°C to 480°C (–320°F to 900°F) (SS Sheath)
Maximum Leadwire exit temperature: 260°C (500°F);
For higher temps, consult factory.
Resistance (Ohms @ 0°C)
100.0 ± 0.1Ω (± 0.12Ω thin film)
200.0 ± 0.2Ω
500.0 ± 0.6Ω thin film
1000.0 ± 1.2Ω thin film
Temperature Coefficients
0.003924 Ω/Ω/°C (RdF Reference)
0.003850 Ω/Ω/°C (IEC/DIN grade)
Accuracy
0.25°C @ 0°C (32°F)
0.3°C @ 0°C (32°F) on IEC/DIN thin film
Stability
Less than 0.05°C shift per year
full span on wire elements,
–50°C to 300°C (–60°F to 575°F) span on thin films

Time Constant without Thermowell
Less than 6 sec. in water flowing at 3 ft. per sec.
Vibration
Sinusoidal 20Hz to 2kHz
Wire Element: 25g Standard Construction
50g Heavy Duty Construction
Thin Film: 80g Standard Construction
Self-Heating
35 mW/°F in water @ 3 ft/sec.
Insulation Resistance
500 Megohms minimum @ 100VDC @ 25°C (77°F)
Recommended Current
1mA maximum
Pressure Rating
3000 PSI
Lead Materials
22 AWG nickel-plated stranded copper,
TFE Teflon® insulated

Teflon® is a registered trademark of the DuPont Corporation.
SCHEMATIC DIAGRAM
LEAD REFERENCE
 
RdF Corporation • 23 Elm Ave., Hudson, NH 03051  
800.445.8367 • 603.882.5195 • fax 603.882.6925 • www.rdfcorp.com