GE XMTC User manual

GE
Measurement & Control Gas Analysis
910-217 Rev. G
October 2013
XMTC
User’s Manual

www.ge-mcs.com
©2013 General Electric Company. All rights reserved.
Technical content subject to change without notice.
XMTC
Thermal Conductivity Binary Gas Transmitter
User’s Manual
910-217 Rev. G
October 2013

ii
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XMTC User’s Manual iii
Preface
Information Paragraphs
Note: These paragraphs provide information that provides a deeper understanding of the situation, but is not
essential to the proper completion of the instructions.
IMPORTANT: These paragraphs provide information that emphasizes instructions that are essential to proper setup of
the equipment. Failure to follow these instructions carefully may cause unreliable performance.
Safety Issues
Auxiliary Equipment
Local Safety Standards
The user must make sure that he operates all auxiliary equipment in accordance with local codes, standards,
regulations, or laws applicable to safety.
Working Area
CAUTION! This symbol indicates a risk of potential minor personal injury and/or severe
damage to the equipment, unless these instructions are followed carefully.
WARNING! This symbol indicates a risk of potential serious personal injury, unless these
instructions are followed carefully.
WARNING! It is the responsibility of the user to make sure all local, county, state and national
codes, regulations, rules and laws related to safety and safe operating conditions are met for
each installation.
WARNING! Auxiliary equipment may have both manual and automatic modes of operation. As
equipment can move suddenly and without warning, do not enter the work cell of this equipment
during automatic operation, and do not enter the work envelope of this equipment during
manual operation. If you do, serious injury can result..
WARNING! Make sure that power to the auxiliary equipment is turned OFF and locked out
before you perform maintenance procedures on the equipment.

Preface
iv XMTC User’s Manual
Auxiliary Equipment (cont.)
Qualification of Personnel
Make sure that all personnel have manufacturer-approved training applicable to the auxiliary equipment.
Personal Safety Equipment
Make sure that operators and maintenance personnel have all safety equipment applicable to the auxiliary equipment.
Examples include safety glasses, protective headgear, safety shoes, etc.
Unauthorized Operation
Make sure that unauthorized personnel cannot gain access to the operation of the equipment.
Environmental Compliance
Waste Electrical and Electronic Equipment (WEEE) Directive
GE Measurement & Control Solutions is an active participant in Europe’s Waste Electrical and Electronic Equipment
(WEEE) take-back initiative, directive 2002/96/EC.
The equipment that you bought has required the extraction and use of natural resources for its production. It may
contain hazardous substances that could impact health and the environment.
In order to avoid the dissemination of those substances in our environment and to diminish the pressure on the natural
resources, we encourage you to use the appropriate take-back systems. Those systems will reuse or recycle most of the
materials of your end life equipment in a sound way.
The crossed-out wheeled bin symbol invites you to use those systems.
If you need more information on the collection, reuse and recycling systems, please contact your local or regional
waste administration.
Visit http://www.ge-mcs.com/en/about-us/environmental-health-and-safety/1741-weee-req.html for
take-back instructions and more information about this initiative.

XMTC User’s Manual v
Contents
Chapter 1. Features and Capabilities
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.2 Basic Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Theory of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
1.4 System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4.1 Packaging and Temperature Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
1.4.2 2-Port (Sealed Reference Gas) Version. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.4.3 4-Port (Flowing Reference Gas) Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4.4 Sample System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
1.4.5 Extra Cable (optional). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4.6 Power Supply (optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
1.4.7 TMO2D-TC Display (optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
1.4.8 XDP Display (Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
1.5 Typical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Chapter 2. Installation
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
2.2 Mounting the XMTC Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
2.3 Mounting the Sample System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
2.3.1 Manual, 2-Port (Sealed Reference Gas) Sample System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
2.3.2 Manual, 4-Port (Flowing Reference Gas) Sample System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.3 Sample Systems with Automatic Switching. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4 Wiring the XMTC Transmitter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
2.4.1 Grounding the Enclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
2.4.2 CE Mark Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
2.4.3 Cable Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
2.4.4 Wiring the Signal Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
2.5 Connecting to Other Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
2.5.1 PS5R-C24 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
2.5.2 TMO2D Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
2.5.3 XDP Display. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
2.5.4 Moisture Series Analyzers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Contents
vi XMTC User’s Manual
Chapter 3. Operation and Programming
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
3.2 Powering Up the XMTC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
3.3 Starting the Sample Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
3.4 Programming with IDM™ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
3.5 The Edit Functions Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
3.6 Field Cal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
3.6.1 Perform Cal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
3.6.2 Configure Cal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
3.6.3 Calibration Drifts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
3.6.4 Clear Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
3.6.5 Hold Last Value. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
3.7 4-20 mA Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
3.7.1 4-20 mA Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
3.7.2 4 and 20 mA Cal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
3.7.3 4-20 mA % Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
3.7.4 % Gas Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
3.8 Error Handler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
3.8.1 Total Drift Error. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
3.8.2 Drift/Cal Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
3.8.3 Gas mV Under/Over Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
3.8.4 Gas % Under/Over Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
3.9 Factory Cal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
3.9.1 Edit # of Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
3.9.2 Edit Point X. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
3.10 The Advanced Option. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
3.10.1 Fast Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
3.10.2 Language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
3.10.3 Meter ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
Chapter 4. Calibration
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
4.2 Gas Ranges and Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
4.3 Required Equipment and Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
4.4 Preparing the Transmitter for Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
4.5 2-Port (Sealed Reference Gas) Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
4.6 4-Port (Flowing Reference Gas) Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Chapter 5. Specifications
5.1 Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
5.2 Functional. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
5.3 Physical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
5.4 Accessories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

XMTC User’s Manual vii
Contents
Appendix A. Supplemental Information
A.1 Ordering Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
A.2 Calibration Specification Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
A.3 XMTC PCB Subassemblies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
A.4 Sample Calibration Sheet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
A.5 Relative Thermal Conductivity of Common Gases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Appendix B. Typical Applications
B.1 H2 in N2 in Heat Treat Furnace Atmospheres. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
B.1.1 Problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
B.1.2 Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
B.1.3 Basic Operating Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
B.1.4 Permanent Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
B.1.5 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
B.1.6 Detailed Operating Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
B.2 H2 Purity in H2-Cooled Electricity Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
B.2.1 Problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
B.2.2 Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
B.2.3 Basic Operating Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
B.2.4 How Previously Handled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66
B.2.5 Permanent Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66
B.2.6 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66
B.2.7 Detailed Operating Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66
Appendix C. Installation and Wiring Diagrams
Appendix D. The Enhanced Advanced Option
D.1 Entering the Enhanced Advanced Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
D.2 Heater. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
D.3 Balance Bridge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88
D.4 Factory Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
D.5 Temperature Comp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91
Appendix E. CE Mark Compliance
E.1 CE Mark Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93
E.2 EMI Filter Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94
E.3 Wiring the Signal Connections for the Weatherproof Version. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95
E.4 Wiring the Signal Connections for the Explosion/Flameproof Version. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97
Appendix F. Certifications
F.1 EC-Type Examination Certificate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99
F.2 IECEx Certificate of Conformity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102

Contents
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XMTC User’s Manual 1
Chapter 1. Features and Capabilities
Chapter 1. Features and Capabilities
1.1 Introduction
This chapter introduces you to the features and capabilities of the GE XMTC Thermal Conductivity Transmitter. The
following topics are discussed:
•Basic features of the XMTC thermal conductivity transmitter
•Theory of operation
•A system description of the XMTC, available options, and sample systems Information on optional
components is also provided, including a 24 VDC power supply, extra cable, and the TMO2D-TC Display.
•A brief discussion of typical XMTC applications
XMTC technical specifications can be found in Chapter 5, Specifications. Ordering information can be found in
Appendix A, Supplemental Information.
1.2 Basic Features
•The XMTC is a transmitter that measures the thermal conductivity of a binary (or pseudo-binary) gas mixture
containing hydrogen, carbon dioxide, methane or helium, and provides a 4-20 mA signal proportional to the
concentration of one of the gases in the mixture. It offers several unique design features:
•Ultra-stable thermistors and a temperature-controlled measuring cell (55°C/131°F standard, 70°C/158°F
optional) provide excellent zero and span stability, as well as tolerance of ambient temperature variations.
•The measuring cell design makes it highly resistant to contamination and flow vibrations. Since it has no
moving parts, the transmitter can handle the shock and vibration found in many industrial applications.
•A 2-port version for measurement of zero-based gas mixtures using a sealed reference gas (air or nitrogen) and
a 4-port version for measurement of zero-suppressed gas mixtures (and some other special calibrations) using a
flowing reference gas are available.
•The XMTC modular construction means that the unit can be field-calibrated quickly and easily. If desired, the
plug-in measuring cell can be replaced with a pre-calibrated spare in minutes.
•The XMTC transmitter, with weatherproof or explosion-proof packaging, is designed to be installed as close as
possible to the process sample point. It can be located up to 4000 ft (1200 m) from a display or recorder, using
inexpensive unshielded cable.

Chapter 1. Features and Capabilities
2XMTC User’s Manual
1.3 Theory of Operation
The XMTC measures the concentration of a gas in a binary gas mixture by measuring the thermal conductivity of the
sample gas and comparing it to the thermal conductivity of a selected reference gas.
Two ultra-stable, glass-coated thermistors are used: one in contact with the sample gas, and the other in contact with a
selected reference gas. The thermistors are mounted so that they are in close proximity to the stainless steel walls of the
sample chamber. The entire sensor is heated to 55°C/131°F, (or 70°C/158°F) and the thermistors are heated above the
sensor temperature using a constant current source. The thermistors lose heat to the walls of the sample chamber at a
rate that is proportional to the thermal conductivity of the gas surrounding them. Thus, each thermistor will reach a
different equilibrium temperature. The temperature difference between the two thermistors is detected in an electrical
bridge circuit. It is then amplified and converted to a 4-20 mA output proportional to the concentration of one of the
constituents of the binary gas mixture. For example:
•To measure 0 to 25% H2in N2, the reference gas would be air (2-port version, sealed reference gas), and for
calibration, the zero gas would be 100% N2 (i.e. 0% H2) and the span gas would be 25% H2in N2.
•To measure 90-100% H2in N2, the reference gas would be 100% H2(4-port version, flowing reference gas),
the zero gas would be 90% H2in N2, and the span gas would be 100% H2(the same as the reference gas).
Note: The XMTC has polarity adjustment jumpers which permit the measurement of gases (such as CO2) that have a
relative thermal conductivity less than air/nitrogen.
Appendix A, Supplemental Information, contains a table of Relative Thermal Conductivity of Common Gases. Figure 1
below shows some of these values graphically.
Figure 1: Relative Thermal Conductivity of Some Common Gases
0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
SO2
CO2
Air/N2
CH4
Ne
He H2
C4H6

XMTC User’s Manual 3
Chapter 1. Features and Capabilities
1.4 System Description
The basic XMTC measurement system consists of an XMTC Transmitter mounted in a sample system. The sample
system is mandatory, and can either be provided by GE or constructed according to GE recommendations. The XMTC
is supplied with a standard 10 ft (3 m), 4-wire cable for power and output connections, with lengths up to 4000 ft
(1200 m) available. Optionally available from GE are a 24-VDC power supply to power the XMTC, a remote display
with programming and control capabilities, and several analyzers which can be interfaced with the XMTC.
1.4.1 Packaging and Temperature Rating
The XMTC transmitter is self-contained, consisting of the thermal conductivity sensor and associated electronics. It
requires 24 VDC power (1.2 A maximum at power-up), and provides a 4-20 mA output signal proportional to the
concentration of one of the gases in the binary sample gas mixture.
The XMTC is designed to be installed in a sample system as close as possible to the process sample point. Thus, it is
available in two environmental packages:
•Weatherproof
•Explosion-proof (with the addition of flame arrestors to the sample/reference gas inlet and outlet)
Each environmental package is available in a standard 2-port (sealed reference gas) version, or an optional 4-port
(flowing reference gas) version.
The XMTC is supplied with a standard measurement cell operating temperature of 55°C (131°F). An optional 70°C
(158°F) cell operating temperature is available.
Note: The 70°C (158°F) operating temperature should be selected only for high temperature applications, because it
results in reduced sensitivity.

Chapter 1. Features and Capabilities
4XMTC User’s Manual
1.4.2 2-Port (Sealed Reference Gas) Version
This standard configuration (see Figure 2 below) is used for zero-based ranges with air or nitrogen at atmospheric
pressure as the balance or background gas. It utilizes air with desiccant in a factory sealed chamber as the reference gas.
The following standard ranges and gases are available:
Figure 2: 2-Port (Sealed Reference Gas) XMTC
Ranges: 0-2% Gases: H2in N2 or air
0-5% CO2in N2or air (min. range 0-5% CO2)
0-10% SO2in air (min. range 0-2% SO2)
0-25% He in N2or air
0-50% Argon in N2or air
0-100%
50-100%
80-100%
90-100%
95-100%
98-100%

XMTC User’s Manual 5
Chapter 1. Features and Capabilities
1.4.3 4-Port (Flowing Reference Gas) Version
This optional configuration shown in Figure 3 below is used for zero-suppressed ranges and some other special
applications. Typically, a flowing reference gas of 100% H2 or CO2is used. The following standard ranges and gases
are available:
Note: For factory calibration pricing on the standard ranges and gases, or for pricing on other zero-suppressed
ranges and gases, please consult the factory.
Figure 3: 4-Port (Flowing Reference Gas) XMTC
Ranges: 90 to 100% Gases: H2in N2
80 to 100% CO2in N2or air
He in N2or air

Chapter 1. Features and Capabilities
6XMTC User’s Manual
1.4.4 Sample System
Use of a sample system is mandatory with the XMTC. The design of the sample system depends on the conditions of
the sample gas and the requirements of the application. In general, a sample system must deliver a clean, representative
sample to the XMTC at a temperature, pressure and flow rate that are within acceptable limits. Standard XMTC sample
conditions are as follows:
•Temperature less than 50oC (122oF) for 55oC cell operating temperature
•Atmospheric pressure
•Flow rate 0.5 SCFH (250 cc/min)
GE offers sample systems for a wide variety of applications. Two standard sample systems for the XMTC are shown in
Chapter 2, Installation. For assistance in designing your own sample system, please consult the factory.
1.4.5 Extra Cable (optional)
GE provides a 10 ft (3 m) length of 4-wire, color-coded cable with each XMTC to connect the power and outputs.
Optional cables are available in lengths up to 4000 ft (1200 m). If you are using your own cable, refer to Table 1 on
page 13 for recommendations.
1.4.6 Power Supply (optional)
The XMTC requires 24 VDC at a maximum start-up current of 1.2 A. The GE PS5R-C24 power supply converts
100/120/220/240 VAC to the required 24 VDC for the XMTC.
1.4.7 TMO2D-TC Display (optional)
The GE TMO2D-TC Display provides a two-line x 24 character back-lit LCD. It also features display and option
programming, recorder outputs, alarm relays, and relays for driving sample system solenoids for automatic zero and
span calibration of the XMTC. For information on the TMO2D-TC, please contact GE.
1.4.8 XDP Display (Optional)
The GE XDP Explosion-proof Display provides an integral, voltage-stabilized 24 VDC power supply, a 3-digit display
with adjustable 4-20 mA input range, two SPDT alarm relays rated for 1 A/250 VAC, and a 4-20 mA output that is
isolated from the input and adjustable to a second independent range if required. For information on the XDP, please
contact GE.

XMTC User’s Manual 7
Chapter 1. Features and Capabilities
1.5 Typical Applications
The XMTC can be used in a wide variety of industrial applications where it is necessary to measure the concentration
of one component of a binary gas mixture. It can also be used in pseudo-binary gas mixtures where the ratio of
concentrations of the background gas components remains constant, and in gaseous mixtures where the thermal
conductivity of the gas of interest is significantly different from that of the background gas. Some typical industries and
applications include:
•Metals Industry -
H2in heat treat furnace atmospheres
•Electric Power Industry -
H2in generator cooling systems
•Gas Production Industry -
Purity monitoring of argon, hydrogen, nitrogen, helium
•Chemical Industry -
H2in ammonia synthesis gas
H2in methanol synthesis gas
H2in chlorine plants
•Food Industry -
CO2in fermentation processes
Ethylene Oxide (ETO) sterilization
•Steel Industry -
H2in blast furnace top gas
•Petroleum Industry -
H2in hydrocarbon streams
Two very common applications are:
•H2in N2in heat treat furnace atmospheres: zero-based 0-25% H2, 2-Port (sealed reference gas, air)
•H2purity in H2electricity generator cooling: zero-suppressed, 80-100% H2, 4-Port (flowing reference gas,
100% H2)
For more details on these applications, refer to Appendix B, Applications. For details on applications not shown in
Appendix B, or if you wish to discuss your own application, please contact GE.

Chapter 1. Features and Capabilities
8XMTC User’s Manual
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XMTC User’s Manual 9
Chapter 2. Installation
Chapter 2. Installation
2.1 Introduction
This chapter describes how to install the XMTC transmitter and its sample system. It also contains information on
connecting the XMTC to optional system components. The following topics are discussed:
•Mounting the XMTC transmitter
•Installing a GE sample system
•Wiring the XMTC transmitter
•Connecting the XMTC transmitter to optional components
2.2 Mounting the XMTC Transmitter
This section applies only if you are mounting the XMTC transmitter in a sample system that has not been supplied by
GE.
Your sample system should deliver a clean, representative sample to the XMTC at the proper temperature, pressure and
flow rate. This usually means a clean, dry sample (free of solid and liquid particulates) at atmospheric pressure; a
temperature no greater than 50°C (122°F); and a flow rate of approximately 0.5 SCFH (250 cc/min). Since factory
calibration of the sensor is at atmospheric pressure and 0.5 SCFH, higher or lower operating pressure may necessitate
field-calibration adjustment.
A simple sample system for a 2-Port XMTC might have inlet and outlet flow-regulating needle valves, a flow meter,
and a pressure gauge, in addition to the XMTC transmitter.
The XMTC transmitter should be mounted in the sample system so that it is upright and level to within ±15°. Also,
provide at least 9 in. (230 mm) of clearance above the top cover of the transmitter to allow access to the transmitter
printed circuit board (PCB) for calibration and maintenance. For a 2-Port XMTC, connect the sample system Sample
Inlet and Sample Outlet ports to the appropriate XMTC port. For a 4-Port system, also connect the Reference Inlet and
Reference Outlet ports to the appropriate XMTC ports.
Note: Refer to Appendix C, Installation and Wiring Diagrams, for port locations and other information.
WARNING! Be sure your installation conforms to all safety and electrical code requirements.

Chapter 2. Installation
10 XMTC User’s Manual
2.3 Mounting the Sample System
You can order a complete sample system from the factory. This includes the XMTC transmitter and all necessary
components and sample tubing mounted on a metal panel. Several standard sample systems are available, and
custom-designed sample systems can be built to your exact specifications.
Mount the sample system as close to the process sample point as possible. Once the sample system is mounted, connect
all inlet and outlet lines via the 1/4” compression fittings on the sample system. The sample line leading from the
process to the sample system should be of 1/4” stainless steel tubing, and should be as short as possible in order to
ensure a representative sample.
Following are descriptions of two standard sample systems:
2.3.1 Manual, 2-Port (Sealed Reference Gas) Sample System
Figure 4 below shows a basic sample system for a 2-Port (sealed reference gas) XMTC. This sample system consists of
inlet needle valves for sample, zero, and span gases; a ball valve; a 2-port XMTC; a pressure gauge; and a flowmeter.
All components are mounted on a painted steel plate. Other components could be added for filtration (filter/coalescer),
pressure control (regulator), or flow control (pump).
Figure 4: Basic 2-Port Sample System (732-164)
SPAN GAS
INLET
9.00
(229.5)
(MIN)
TRANSMITTER
SAMPLE GAS
INLET
ZERO GAS
INLET
SAMPLE GAS
OUTLET