OMEGA PRS-3 Manual

User’s Guide

NORWALK, CT

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CONNECTION HEAD STYLE

PRS SERIES

Spring Loaded Sanitary

RTD Sensors with Thermowells

M-4913-J Instruction Manual for Connection Head Style PRS Series

Spring Loaded Sanitary RTD Sensors With Thermowells

GENERAL DESCRIPTION

The OMEGA PRS series sensors are
designed for use in Sanitary Clean-In-Place
(CIP) systems, and are supplied with a
Tri-Grip

®

flanged thermowell for easy
installation into Food, Dairy and
Biopharmaceutical systems. These sensors
are supplied with a stainless steel
thermowell, a spring loaded probe assembly
and White Polypropylene (NB9W) or 316L
Stainless Steel (NB15) connection heads
standard.

When assembled, the probe is spring loaded
into the thermowell through a spring loading
arrangement housed in the pipe nipple
connecting the thermowell and the
connection head. The probe contains a
4-wire PT100 Platinum RTD (Resistance
Temperature Detector) that meets the
resistance vs. temperature characteristics
and Class A requirements of IEC 60751.
Equations for calculating resistance vs.
temperature, temperature vs. resistance, and
Class A tolerances are included below the
resistance vs. temperature table.

PROCESS CONNECTION

This sensor has a thermowell that includes a
Tri-Grip

®

flange so it can be installed into
existing process connections. A commercially
available gasket is placed between the
thermowell flange and process connection,
with a clamp used to complete the connection
as shown above.

The Thermowell is made from 316L Stainless
Steel, with wetted surfaces that have a surface
finish of 32 microinches or better. Care should
be exercised when handling sensors so that the
surface finish is not damaged during handling
or installation.

WIRING CONFIGURATION:

The Omega PRS Style sensors are supplied
with 4-wire connections as shown in the
schematic diagrams below. The sensor
wiring is connected to the four inner screws
of the terminal board (see image below),
leaving the outer terminals available for
instrument connections. For 4-wire PT100
RTD connections, simply connect to the two
red and two white wires (note: RTD sensors
have no polarity). If three wire connections
are required, simply do not connect to one of
the red or white wire terminals.

OPERATING CURRENT:

To insure self heating effects do not occur,
the Omega PRS series sensors should be
powered with no more than 1 milliamp of
excitation current. Although capable of
operating at higher current levels, self heating
effects may occur.

SPECIFICATIONS:
RTD Type: Platinum per IEC-60751.
Accuracy: Class A per IEC-60751.
Temperature Range: -50 to 250°C.
Excitation Current: 1 milliamp max.
Response Time: 2.5 Seconds max (63%).
Wetted Surfaces: 316L Stainless Steel with

10 microinch or better surface finish.
Connection Head: White Polypropylene
with NPT Cable Connection (NB9W

3/4"

Style).

M-4913-J Instruction Manual for Connection Head Style PRS Series

Spring Loaded Sanitary RTD Sensors With Thermowells

Resistance Vs. Temperature Table: (Resistance Values Stated in Ohms)

Temperature °C

0 1 2 3 4 5 6 7 8 9

-50 80.32 79.92 79.52 79.13 78.73 78.33 77.93 77.54 77.14 76.74

-40 84.28 83.88 83.48 83.09 82.69 82.30 81.90 81.50 81.11 80.71

-30 88.22 87.83 87.44 87.04 86.65 86.25 85.86 85.46 85.07 84.67

-20 92.16 91.77 91.37 90.98 90.59 90.19 89.80 89.41 89.01 88.62

-10 96.09 95.69 95.30 94.91 94.52 94.13 93.73 93.34 92.95 92.55

100.00 99.61 99.22 98.83 98.44 98.04 97.65 97.26 96.87 96.48

0

100.00 100.39 100.78 101.17 101.56 101.95 102.34 102.73 103.12 103.51

10 103.90 104.29 104.68 105.07 105.46 105.85 106.24 106.63 107.02 107.40
20 107.79 108.18 108.57 108.96 109.35 109.73 110.12 110.51 110.90 111.29

30 111.67 112.06 112.45 112.83 113.22 113.61 114.00 114.38 114.77 115.15

40 115.54 115.93 116.31 116.70 117.08 117.47 117.86 118.24 118.63 119.01

50 119.40 119.78 120.17 120.55 120.94 121.32 121.71 122.09 122.47 122.86
60 123.24 123.63 124.01 124.39 124.78 125.16 125.54 125.93 126.31 126.69
70 127.08 127.46 127.84 128.22 128.61 128.99 129.37 129.75 130.13 130.52

80 130.90 131.28 131.66 132.04 132.42 132.80 133.18 133.57 133.95 134.33

90 134.71 135.09 135.47 135.85 136.23 136.61 136.99 137.37 137.75 138.13
100 138.51 138.88 139.26 139.64 140.02 140.40 140.78 141.16 141.54 141.91

110 142.29 142.67 143.05 143.43 143.80 144.18 144.56 144.94 145.31 145.69
120 146.07 146.44 146.82 147.20 147.57 147.95 148.33 148.70 149.08 149.46
130 149.83 150.21 150.58 150.96 151.33 151.71 152.08 152.46 152.83 153.21
140 153.58 153.96 154.33 154.71 155.08 155.46 155.83 156.20 156.58 156.95
150 157.33 157.70 158.07 158.45 158.82 159.19 159.56 159.94 160.31 160.68
160 161.05 161.43 161.80 162.17 162.54 162.91 163.29 163.66 164.03 164.40
170 164.77 165.14 165.51 165.89 166.26 166.63 167.00 167.37 167.74 168.11
180 168.48 168.85 169.22 169.59 169.96 170.33 170.70 171.07 171.43 171.80
190 172.17 172.54 172.91 173.28 173.65 174.02 174.38 174.75 175.12 175.49
200 175.86 176.22 176.59 176.96 177.33 177.69 178.06 178.43 178.79 179.16
210 179.53 179.89 180.26 180.63 180.99 181.36 181.72 182.09 182.46 182.82
220 183.19 183.55 183.92 184.28 184.65 185.01 185.38 185.74 186.11 186.47
230 186.84 187.20 187.56 187.93 188.29 188.66 189.02 189.38 189.75 190.11
240 190.47 190.84 191.20 191.56 191.92 192.29 192.65 193.01 193.37 193.74
250 194.10 194.46 194.82 195.18 195.55 195.91 196.27 196.63 196.99 197.35
260 197.71 198.07 198.43 198.79 199.15 199.51 199.87 200.23 200.59 200.95

For Determining Resistance from
Temperature (0°C and above):
Rt = R0(1 + At + B
where:
R

= Sensor Resistance at Temperature (°C)

t

R

= Sensor resistance at 0°C

0

= (100 Ohms Nominal)
A = 3.9083 x 10
B = -5.775 x 10

t

-3 °C-1

-7 °C-2

2

)

For Determining Temperature From
Resistance (0°C and above):
t = [sqrt(A2-4B(1-Rt/R0))-A]/2B = °C
where:
t = Temperature at Sensor Resistance R
A, B, R0 and Rt per above
Class A Tolerance = ± (0.15 + 0.002t) = °C
With t = temperature in °C regardless to sign

t

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Servicing North America:

U.S.A. Omega Engineering, Inc.
Headquarters: Toll-Free: 1-800-826-6342 (USA & Canada only)

Customer Service: 1-800-622-2378 (USA & Canada only)
Engineering Service: 1-800-872-9436 (USA & Canada only)
Tel: [phone] Fax: [phone]
e-mail: [e-mail]

For Other Locations Visit omega.com/worldwide

The information contained in this document is believed to be correct, but OMEGA accepts no liability for any errors it
contains, and reserves the right to alter specifications without notice.

DISCLAIMER

If the unit malfunctions, it must be returned to the factory for evaluation. OMEGA’s Customer Service Department
will issue an Authorized Return (AR) number immediately upon phone or written request. Upon examination by
OMEGA, if the unit is found to be defective, it will be repaired or replaced at no charge. OMEGA’s WARRANTY does
not apply to defects resulting from any action of the purchaser, including but not limited to mishandling, improper
interfacing, operation outside of design limits, improper repair, or unauthorized modification. This WARRANTY is
VOID if the unit shows evidence of having been ta
result of excessive corrosion; or current, heat, moisture or vibration; improper specification; misapplication;
misuse or other operating conditions outside of OMEGA’s control. Components in which wear is not warranted,
include but are not limited to contact points, fuses, and triacs.

OMEGA is pleased to offer suggestions on the use of its various products. However, OMEGA
neither assumes responsibility for any omissions or errors nor assumes liability for any damages that
result from the use of its products in accordance with information provided by OMEGA, either
verbal or written. OMEGA warrants only that the parts manufactured by the company will be as
specified and free of defects. OMEGA MAKES NO OTHER WARRANTIES OR REPRESENTATIONS OF
ANY KIND WHATSOEVER, EXPRESSED OR IMPLIED, EXCEPT THAT OF TITLE, AND ALL IMPLIED
WARRANTIES INCLUDING ANY WARRANTY OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. LIMITATION OF LIABILITY: The remedies of
purchaser set forth herein are exclusive, and the total liability of OMEGA with respect to this order,
whether based on contract, warranty, negligence, indemnification, strict liability or otherwise, shall not
exceed the purchase price of the component upon which liability is based. In no event shall OMEGA be
liable for consequential, incidental or special damages.

CONDITIONS: Equipment sold by OMEGA is not intended to be used, nor shall it be used: (1) as a “Basic
Component” under 10 CFR 21 (NRC), used in or with any nuclear installation or activity; or (2) in medical
applications or used on humans. Should any Product(s) be used in or with any nuclear installation or activity,
medical application, used on humans, or misused in any way, OMEGA assumes no responsibility as set forth in our
basic WARRANTY / DISCLAIMER language, and, additionally, purchaser will indemnify OMEGA and hold OMEGA
harmless from any liability or damage whatsoever arising out of the use of the Product(s) in such a manner.

Direct all warranty and repair requests/inquiries to the OMEGA Customer Service Department. BEFORE RETURNING
ANY PRODUCT(S) TO OMEGA, PURCHASER MUST OBTAIN AN AUTHORIZED RETURN (AR) NUMBER FROM
OMEGA’S CUSTOMER SERVICE DEPARTMENT (IN ORDER TO AVOID PROCESSING DELAYS). The assigned AR
number should then be marked on the outside of the return package and on any correspondence.

The purchaser is responsible for shipping charges, freight, insurance and proper packaging to prevent breakage
in transit.

FOR WARRANTY RETURNS, please have the following
information available BEFORE contacting OMEGA:

1. Purchase Order number under which the product was
PURCHASED,

2. Model and serial number of the product under warranty,
and

3. Repair instructions and/or specific problems relative to the
product.

OMEGA’s policy is to make running changes, not model changes, whenever an improvement is possible. This affords our
customers the latest in technology and engineering. OMEGA is a trademark of OMEGA ENGINEERING, INC.

© Copyright 2018 OMEGA ENGINEERING, INC. All rights reserved. This document may not be copied, photocopied, reproduced,
translated, or reduced to any electronic medium or machine-readable form, in whole or in part, without the prior written consent of
OMEGA ENGINEERING, INC.

RETURN REQUESTS / INQUIRIES

mpered with or shows evidence of having been damaged as a

FOR NON-WARRANTY REPAIRS,
repair charges. Have the following information available
BEFORE contacting OMEGA:

1. Purchase Order number to cover the COST of the repair,

2. Model and serial number of the product, and

3. Repair instructions and/or specific problems relative to the
product.

consult OMEGA for current

M4913-J/0418