Vaisala OMT355 User Manual
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USER'S GUIDE
Vaisala SPECTRACAP®
Oxygen Transmitte
OMT355
M210735EN-D
PUBLISHED BY
Vaisala Oyj Phone (int.): +358 9 8949 1
P.O. Box 26 Fax: +358 9 8949 2227
FIN-00421 Helsinki
Finland
Visit our Internet pages at http://www.vaisala.com/
© Vaisala 2008
No part of this manual may be reproduced in any form or by any means,
electronic or mechanical (including photocopying), nor may its contents
be communicated to a third party without prior written permission of the
copyright holder.
The contents are subject to change without prior notice.
Please observe that this manual does not create any legally binding
obligations for Vaisala towards the customer or end user. All legally
binding commitments and agreements are included exclusively in the
applicable supply contract or Conditions of Sale.
________________________________________________________________________________
Table of Contents
CHAPTER 1
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
General Safety Considerations . . . . . . . . . . . . . . . . . . . . .11
Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Product Related Safety Precautions . . . . . . . . . . . . . . . . . .12
ESD Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Recycling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Regulatory Compliances . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
License Agreement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
CHAPTER 2
PRODUCT OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Introduction to Vaisala SPECTRACAP® Oxygen
Transmitter OMT355 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Oxygen Measurement Range . . . . . . . . . . . . . . . . . . . . . . . .17
OMT355 for In-Line and Sampling Cell Mounting . . . . . . .18
Ambient Gas Measurement Version of OMT355 . . . . . . . .20
CHAPTER 3
FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Measurement Principle and Sensor Technology . . . . . . . .21
Construction of OMT355 Probe . . . . . . . . . . . . . . . . . . . . . .23
Eye Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
CHAPTER 4
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Selecting Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Chemical Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
OMT355 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Temperature Conditions of Installation Location . . . . . . . .27
Powerful Light Sources Near the Oxygen Measurement
Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Maximum Allowed Installation Angle . . . . . . . . . . . . . . . . .28
Mounting Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Process Conditions in Regard to Mounting Options . . . . .29
Flange Mounted for In-Line Process Gas Measurement . .31
VAISALA________________________________________________________________________ 1
________________________________________________________________________________
Suitable Process Flanges . . . . . . . . . . . . . . . . . . . . . . 31
Filter Recommendation . . . . . . . . . . . . . . . . . . . . . . . . 31
Mounting with Flange Adapter . . . . . . . . . . . . . . . . . . . 32
Mounting with Sampling Cell . . . . . . . . . . . . . . . . . . . . . . .34
Filter Recommendation . . . . . . . . . . . . . . . . . . . . . . . . 34
Mounting with Wall Mounting Bracket . . . . . . . . . . . . . 36
Tubing Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Installation Instructions for Swagelok Tube Fittings 36
Sampling Cell Instructions . . . . . . . . . . . . . . . . . . . . . . 37
Mounting OMT355 for Ambient Gas Measurement . . . . . .39
Mounting Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
Signal and Power Supply Wiring . . . . . . . . . . . . . . . . . . . .41
Connecting OMT355 with Optional 8-Pin Connector. . 44
CHAPTER 5
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Device Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Keypad, Display and LEDs . . . . . . . . . . . . . . . . . . . . . . . .45
Service Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Installing the Driver for the USB Cable . . . . . . . . . . . . 46
Customer Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Analog Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Local Interface (Keypad and Display) . . . . . . . . . . . . . . . . .48
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
Display Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
Start-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Normal Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Error Condition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Warning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Service Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Customer Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
General Instructions for Using Functions . . . . . . . . . . . . . .52
Menu Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Serial Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
List of Serial Commands . . . . . . . . . . . . . . . . . . . . . . . . . .57
Outputting Measurement Results . . . . . . . . . . . . . . . . . . . .58
Start Continuous Output Command (R) . . . . . . . . . . . . . . .58
Stop Continuous Output Command (S) . . . . . . . . . . . . . . .59
Show/Set Continuous Output Interval Command (INTV) . .59
Send Measurement Results Command (SEND) . . . . . . . .59
Show/Set Serial Communications Mode Command
(SMODE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
Show/Set Serial Communications Mode for Line 2
Command (SMODE2) . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
Show/Set Serial Communications Settings Command
(SERI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
2 _______________________________________________________________________________
________________________________________________________________________________
Show/Set Serial Communication Settings for Line 2
Command (SERI2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62
Show Serial Line 1 Status Command (SCI1) . . . . . . . . . . .63
Show Serial Line 2 Status Command (SCI2) . . . . . . . . . . .63
Show Measurement Status Command (MEA) . . . . . . . . . .64
Oxygen Statistics Display Function . . . . . . . . . . . . . . . . . .64
Temperature Statistics Display Function . . . . . . . . . . . . . .65
Formatting Measurement Results . . . . . . . . . . . . . . . . . . . .65
Set Output Format Command (FORM) . . . . . . . . . . . . . . .65
Show/Set Date Command (DATE) . . . . . . . . . . . . . . . . . .67
Show/Set Time Command (TIME) . . . . . . . . . . . . . . . . . . .68
Networking Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69
Show/Set Device Address Command (ADDR) . . . . . . . . .69
Open Communications Line Command (OPEN) . . . . . . . .69
Close Serial Line in Poll Mode Command (CLOSE) . . . . .70
Set Echoing Mode Command (ECHO) . . . . . . . . . . . . . . .70
Accessing Service Level Commands . . . . . . . . . . . . . . . . .71
Issue Password Command (PASS) . . . . . . . . . . . . . . . . . .71
Issue Password Function (Pas) . . . . . . . . . . . . . . . . . . . . .72
Analog Output Calibration . . . . . . . . . . . . . . . . . . . . . . . . . .73
Calibrate Analog Output Command (ICAL) . . . . . . . . . . . .73
Analog Output Scaling and Settings . . . . . . . . . . . . . . . . . .73
Scale Analog Output Function (Ascl) . . . . . . . . . . . . . . . . .73
Show/Set Output Parameters Command (OUT_PARAMS) 75
Analog Output Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75
Set Test Current to Analog Output Command (ITEST) . . .75
Test Analog Output Function (Aou) . . . . . . . . . . . . . . . . . .76
Relay Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
Show/Set Relay Operating Mode Command
(RELAY_MODE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
Show/Set Relay Trigger Points Command (RSEL) . . . . . .78
Test Alarm Relay Function (Ala) . . . . . . . . . . . . . . . . . . . .78
Device Information and Other General Commands . . . . . .79
Show Information about the Device Command (?) . . . . . .79
Show Information about the Device Overriding POLL
Mode Command (??) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Show Measuring Parameters Command (CALCS) . . . . . .80
Show Calibration Information (CINFO) . . . . . . . . . . . . . . .80
Show Display Board Status Command (DB) . . . . . . . . . . .81
List Commands Command (HELP) . . . . . . . . . . . . . . . . . .81
Show Laser Temperature Controller Status Command
(LTC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
Show Output Status Command (OUT) . . . . . . . . . . . . . . .82
Show All Modifiable Parameter Values (PARAM) . . . . . . .83
Measure Signal Level Command (SIL) . . . . . . . . . . . . . . .84
Signal Level Display Function (Sil) . . . . . . . . . . . . . . . . . .84
Show Statistical Information Command (STATS) . . . . . . .85
Show Status of Subfunctions Command (STATUS) . . . . .85
Show Product Name and Software Version Command
(VERS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
VAISALA________________________________________________________________________ 3
________________________________________________________________________________
Memory Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Save Parameters Command (SAVE) . . . . . . . . . . . . . . . . .86
Resetting the Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . .87
Reset Command (RESET) . . . . . . . . . . . . . . . . . . . . . . . . .87
Reset Function (Off) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87
CHAPTER 6
SETTING ENVIRONMENTAL PARAMETERS . . . . . . . . . . . . . . . . . . . . . .89
Environmental Parameter Compensations . . . . . . . . . . . . .89
Operating Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . .90
Operating Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90
Show/Set Pressure for Compensation Command
(PRES). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Set Pressure for Compensation Command (XPRES) . 93
Set (Average) Process Pressure Function (App). . . . . 93
Background Gas Effects . . . . . . . . . . . . . . . . . . . . . . . . . .94
General Information About Background Gas Effects. . 94
Water Content of Background Gas . . . . . . . . . . . . . . . 95
Set Water Content for Compensation Command (H2O) 97
Set (Average) Water Content Function (H2O). . . . . . . 98
CO2 Concentration of Background Gas. . . . . . . . . . . . 98
Set Carbon Dioxide Content for Compensation
Command (CO2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Set (Average) Carbon Dioxide Content Function (CO2) 99
Setting Several/All Environmental Parameters with
Single Command (ENV) . . . . . . . . . . . . . . . . . . . . . . . . . .100
CHAPTER 7
CALIBRATION AND ADJUSTMENT (IN-LINE AND SAMPLING CELL
VERSIONS OF OMT355) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
Hardware Arrangements for Calibration and
Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102
Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102
Gas Feed Setup for Calibration and Adjustment . . . . . . .102
Using Ambient Air . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Using Bottled Gas and Calibration Chamber. . . . . . . 103
Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Calibration or Adjustment in Process. . . . . . . . . . . . . 103
Connections and Systems . . . . . . . . . . . . . . . . . . 104
Preparations for Adjustment . . . . . . . . . . . . . . . . . 104
Connecting the Gas . . . . . . . . . . . . . . . . . . . . . . . 104
Adjusting Gas Flow. . . . . . . . . . . . . . . . . . . . . . . . 105
Information on Calibration Gases. . . . . . . . . . . . . . . . 106
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107
Using Ambient Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107
Using Calibration Gases . . . . . . . . . . . . . . . . . . . . . . . . .108
Calibration Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . .108
Lock Outputs for Calibration Command (ADJUST) . . . . .108
Calibration Check Function (Cal.C) . . . . . . . . . . . . . . . . .109
Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109
4 _______________________________________________________________________________
________________________________________________________________________________
Possible Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . .110
One-Point Adjustment Using Serial Line . . . . . . . . . . . . .110
Make One-Point Adjustment Command (COXY1). . . 110
One-Point Adjustment Procedure Using Serial Line . 111
One-Point Adjustment Using Local Interface . . . . . . . . . .113
One-Point Adjustment Function (CAL1). . . . . . . . . . . 113
One-Point Adjustment Procedure Using Local
Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Two-Point Adjustment Using Serial Line . . . . . . . . . . . . .115
Make Two-Point Adjustment Command (COXY2). . . 115
Two-Point Adjustment Procedure Using Serial Line . 116
Two-Point Adjustment Using Local Interface . . . . . . . . . .119
Two-Point Adjustment Function (CAL2). . . . . . . . . . . 119
Two-Point Adjustment Procedure Using Local
Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Restoring Factory Calibration . . . . . . . . . . . . . . . . . . . . .121
Restore Factory Calibration Command
(FCRESTORE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Restore Factory Calibration Function (Fac). . . . . . . . 121
CHAPTER 8
CALIBRATION AND ADJUSTMENT (AMBIENT GAS MEASUREMENT
VERSION OF OMT355) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123
Hardware Arrangements for Calibration and
Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124
Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124
Gas Feed Setup for Calibration and Adjustment . . . . . . .125
Using Ambient Air . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Using Bottled Calibration Adjustment Gas. . . . . . . . . 125
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .126
Using Ambient Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .126
Using Calibration Gas . . . . . . . . . . . . . . . . . . . . . . . . . . .127
Information on Calibration Gases . . . . . . . . . . . . . . . . . .129
Calibration Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . .129
Lock Outputs for Calibration Command (ADJUST) . . . . .129
Calibration Check Function (Cal.C) . . . . . . . . . . . . . . . . .130
Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130
Possible Adjustments for Ambient Measurement Version 131
One-Point Adjustment Using Serial Line . . . . . . . . . . . . .132
One-Point Adjustment Command (COXY1). . . . . . . . 132
One-Point Adjustment Procedure Using Serial Line . 133
One-Point Adjustment Using Local Interface . . . . . . . . . .135
One-Point Adjustment Function (CAL1). . . . . . . . . . . 135
One-Point Adjustment Procedure Using Local
Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Restoring Factory Calibration . . . . . . . . . . . . . . . . . . . . .136
Restore Factory Calibration Command
(FCRESTORE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Restore Factory Calibration Function (Fac). . . . . . . . 137
VAISALA________________________________________________________________________ 5
________________________________________________________________________________
CHAPTER 9
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
Field Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
Cleaning the Optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
Using Solvents to Clean the Optics . . . . . . . . . . . . . . 140
Cleaning the Mirror. . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Cleaning the Lens . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Replacing Consumables . . . . . . . . . . . . . . . . . . . . . . . . . . .142
OMT355 Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .142
Filter Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .142
Cleaning and Changing the Stainless Steel Mesh
Filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Changing the PTFE Filter. . . . . . . . . . . . . . . . . . . . . . 143
Spare Parts and Accessories . . . . . . . . . . . . . . . . . . . . . .144
CHAPTER 10
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .145
Operation Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .145
Self-Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .145
Error Detection During Operation . . . . . . . . . . . . . . . . . . .146
Error Control and Error Categories . . . . . . . . . . . . . . . . .147
Fatal Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Nonfatal Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Emergency Shutdown State . . . . . . . . . . . . . . . . . . . 149
Show Error Control Status (ERR) . . . . . . . . . . . . . . . . . .149
Show Error Log (ERRL) . . . . . . . . . . . . . . . . . . . . . . . . . .150
Show Detected Errors (ERRS) . . . . . . . . . . . . . . . . . . . . .150
Show Error Table (ERRT) . . . . . . . . . . . . . . . . . . . . . . . .150
Error Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151
Error Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151
Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .152
Return Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .152
Vaisala Service Centers . . . . . . . . . . . . . . . . . . . . . . . . . . .153
CHAPTER 11
TECHNICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .155
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .155
APPENDIX A
FLANGE PREPARATION INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . .159
APPENDIX B
HUMIDITY CONVERSION TABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .161
6 _______________________________________________________________________________
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List of Figures
Figure 1 Flange Mounted Vaisala SPECTRACAP® Oxygen
Transmitter OMT355 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Figure 2 OMT355 with Sampling Cell. . . . . . . . . . . . . . . . . . . . . . . . . . .19
Figure 3 OMT355 for Ambient Gas Measurement. . . . . . . . . . . . . . . . .20
Figure 4 O2 Absorption Spectrum Around the 760 nm Near Infrared
Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Figure 5 Adjacent O2 Absorption Lines and Laser Emission Peak . . . .22
Figure 6 Schematic of Probe Design . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Figure 7 OMT355 Laser Eye Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Figure 8 OMT355 Dimensions in mm. . . . . . . . . . . . . . . . . . . . . . . . . . .26
Figure 9 Installation Angle Limitations in High Humidities . . . . . . . . . . .29
Figure 10 OMT355 Transmitter with Flange Adapter. . . . . . . . . . . . . . . .31
Figure 11 Dimensions, OMT 355 Flange Mounted . . . . . . . . . . . . . . . . .33
Figure 12 OMT355 Transmitter with Sampling Cell. . . . . . . . . . . . . . . . .34
Figure 13 Sample Gas Treatment System. . . . . . . . . . . . . . . . . . . . . . . .35
Figure 14 Swagelok Tube Fitting Instructions . . . . . . . . . . . . . . . . . . . . .37
Figure 15 Detaching Sampling Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Figure 16 Dimensions, OMT355 with Sampling Cell . . . . . . . . . . . . . . . .38
Figure 17 OMT355 for Ambient Gas Measurement with Wall Mounting
Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
Figure 18 OMT355 Wall Mounted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
Figure 19 Dimensions and Drilling Holes, Wall Mounting Bracket (Right)
and Flange Adapter (Left) . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
Figure 20 Connections/Local Interface Layout. . . . . . . . . . . . . . . . . . . . .42
Figure 21 Optional 8-Pin Connector. . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Figure 22 OMT355 Display Layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
Figure 23 Effect of Process Pressure Compensation . . . . . . . . . . . . . . .91
Figure 24 Attaching OMT355 Probe into Calibration Chamber . . . . . . .103
Figure 25 Flow Rate vs. Pressure, Back Pressure Valve Swagelok
SS-CHSM2-KZ-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106
Figure 26 Oxygen Readings in Relative Humidity . . . . . . . . . . . . . . . . .108
Figure 27 Attaching OMT355 Probe into Sample Cell . . . . . . . . . . . . . .126
Figure 28 Oxygen Readings in Alternating Humidity . . . . . . . . . . . . . . .127
Figure 29 Calibration Gas O2 Concentration Readings for Ambient
Gas Measurement Version of OMT355 . . . . . . . . . . . . . . . . .128
Figure 30 Location of Mirror in Oxygen Measurement Probe . . . . . . . .140
Figure 31 Location of Lens in Oxygen Measurement Probe . . . . . . . . .141
Figure 32 Stainless Steel Mesh and PTFE Filters . . . . . . . . . . . . . . . . .142
VAISALA________________________________________________________________________ 7
________________________________________________________________________________
8 _______________________________________________________________________________
________________________________________________________________________________
List of Tables
Table 1 Chemical tolerance of sealing materials . . . . . . . . . . . . . . . . . . .26
Table 2 Process Conditions and Mounting Options . . . . . . . . . . . . . . . . .30
Table 3 8-Pin Connector Terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Table 4 Meaning of the Command Line Elements . . . . . . . . . . . . . . . . . .56
Table 5 OMT355 Default Serial Communication Settings. . . . . . . . . . . . .56
Table 6 List of Serial Commands without Password. . . . . . . . . . . . . . . . .57
Table 7 List of Additional Serial Commands with Password Given. . . . . .57
Table 8 Format String Abbreviations and Quantities . . . . . . . . . . . . . . . .66
Table 9 Format String Modifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66
Table 10 Conversion Table from T and RH to Absolute Humidity and the
Effect of Humidity on Transmitter Reading . . . . . . . . . . . . . . . . .96
Table 11 Available Spare Parts and Accessories. . . . . . . . . . . . . . . . . . . .144
Table 12 Actions When Fatal Error Has Been Detected. . . . . . . . . . . . . . .147
Table 13 Actions When Nonfatal Error Has Been Detected . . . . . . . . . . . .148
Table 14 Actions When Warning Has Been Detected . . . . . . . . . . . . . . . .148
Table 15 Emergency Shutdown Actions. . . . . . . . . . . . . . . . . . . . . . . . . . .149
Table 16 Error Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151
Table 17 Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .155
Table 18 Background Gas Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156
Table 19 Operating Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156
Table 20 Inputs and Outputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156
Table 21 Approvals and Fulfilled Standards . . . . . . . . . . . . . . . . . . . . . . . .157
Table 22 Dimensions and Mechanics. . . . . . . . . . . . . . . . . . . . . . . . . . . . .158
Table 23 Options and Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .158
VAISALA________________________________________________________________________ 9
________________________________________________________________________________
10 ______________________________________________________________________________
Chapter 1 ________________________________________________________ General Information
CHAPTER 1
GENERAL INFORMATION
About This Manual
WARNING
CAUTION
This manual provides information for installing, operating, and
maintaining Vaisala SPECTRACAP® Oxygen Transmitter OMT355.
General Safety Considerations
Throughout the manual, important safety considerations are highlighted
as follows:
Warning alerts you to a serious hazard. If you do not read and follow
instructions very carefully at this point, there is a risk of injury or even
death.
Caution warns you of a potential hazard. If you do not read and follow
instructions carefully at this point, the product could be damaged or
important data could be lost.
NOTE
VAISALA_______________________________________________________________________ 11
Note highlights important information on using the product.
User's Guide ______________________________________________________________________
Feedback
Vaisala Customer Documentation Team welcomes your comments and
suggestions on the quality and usefulness of this publication. If you find
errors or have other suggestions for improvement, please indicate the
chapter, section, and page number. You can send comments to us by email: manuals@vaisala.com.
Product Related Safety Precautions
The Vaisala SPECTRACAP® Oxygen Transmitter OMT355 delivered
to you has been tested for safety and approved as shipped from the
factory. The wetted components of the transmitter are oxygen
compatible, and have been cleaned at the factory to ensure that they can
be safely placed in 100% oxygen. Only oxygen compatible lubricant
(Krytox 240 AC) has been used in the assembly.
WARNING
CAUTION
CAUTION
Note the following precautions:
Ground the product, and verify outdoor installation grounding
periodically to minimize shock hazard.
Do not modify the unit. Improper modification can damage the
product or lead to malfunction.
The OMT355 is a Class 1 laser product.
Normal handling and operation of the device is eye-safe, because laser
radiation is collimated and maintained inside the probe, as is
schematically shown in Figure 7 on page 24. No laser radiation is
emitted outside the probe. Avoid placing reflective surfaces (tools,
etc.) directly into the probe when the transmitter is in operation, since
this might cause reflection of laser radiation outside the probe.
12 __________________________________________________________________ M210735EN-D
Chapter 1 ________________________________________________________ General Information
Recycle all applicable material.
Dispose of batteries and the unit according to statutory regulations.
Do not dispose of with regular household refuse.
ESD Protection
Electrostatic Discharge (ESD) can cause immediate or latent damage to
electronic circuits. Vaisala products are adequately protected against
ESD for their intended use. However, it is possible to damage the
product by delivering electrostatic discharges when touching,
removing, or inserting any objects inside the equipment housing.
To make sure you are not delivering high static voltages yourself:
- Handle ESD sensitive components on a properly grounded and
protected ESD workbench. When this is not possible, ground
yourself with a wrist strap and a resistive connection cord to the
equipment chassis before touching the boards. When neither of the
above is possible, at least touch a conductive part of the equipment
chassis with your other hand before touching the boards.
- Always hold the boards by the edges and avoid touching the
component contacts.
Recycling
VAISALA_______________________________________________________________________ 13
User's Guide ______________________________________________________________________
Regulatory Compliances
The OMT355 is classified as Class 1 laser device in accordance with
IEC 60825-1.
Trademarks
SPECTRACAP® is a registered trademark of Vaisala. Kalrez® and
®
Krytox
are registered trademarks of DuPont.
License Agreement
All rights to any software are held by Vaisala or third parties. The
customer is allowed to use the software only to the extent that is
provided by the applicable supply contract or Software License
Agreement.
14 __________________________________________________________________ M210735EN-D
Chapter 1 ________________________________________________________ General Information
Warranty
Vaisala hereby represents and warrants all Products
manufactured by Vaisala and sold hereunder to be free
from defects in workmanship or material during a
period of twelve (12) months from the date of delivery
save for products for which a special warranty is given.
If any Product proves however to be defective in
workmanship or material within the period herein
provided Vaisala undertakes to the exclusion of any
other remedy to repair or at its own option replace the
defective Product or part thereof free of charge and
otherwise on the same conditions as for the original
Product or part without extension to original warranty
time. Defective parts replaced in accordance with this
clause shall be placed at the disposal of Vaisala.
Vaisala also warrants the quality of all repair and
service works performed by its employees to products
sold by it. In case the repair or service works should
appear inadequate or faulty and should this cause
malfunction or nonfunction of the product to which the
service was performed Vaisala shall at its free option
either repair or have repaired or replace the product in
question. The working hours used by employees of
Vaisala for such repair or replacement shall be free of
charge to the client. This service warranty shall be
valid for a period of six (6) months from the date the
service measures were completed.
This warranty does not however apply when the defect
has been caused through
a) normal wear and tear or accident;
b) misuse or other unsuitable or unauthorized use of
the Product or negligence or error in storing,
maintaining or in handling the Product or any
equipment thereof;
c) wrong installation or assembly or failure to se rv ice
the Product or otherwise follow Vaisala's service
instructions including any repairs or installation or
assembly or service made by unauthorized personnel
not approved by Vaisala or replacements with parts not
manufactured or supplied by Vaisala;
d) modifications or changes of the Product as well as
any adding to it without Vaisala's prior authorization;
e) other factors depending on the Customer or a third
party.
Notwithstanding the aforesaid Vaisala's liability under
this clause shall not apply to any defects arising out of
materials, designs or instructions provided by the
Customer.
This warranty is however subject to following
conditions:
a) A substantiated written claim as to any alleged
defects shall have been received by Vaisala within
thirty (30) days after the defect or fault became known
or occurred, and
b) The allegedly defective Product or part shall, should
Vaisala so require, be sent to the works of Vaisala or to
such other place as Vaisala may indicate in writing,
freight and insurance prepaid and properly packed and
labelled, unless Vaisala agrees to inspect and repair the
Product or replace it on site.
This warranty is expressly in lieu of and excludes all
other conditions, warranties and liabilities, express or
implied, whether under law, statute or otherwise,
including without limitation any implied warranties of
merchantability or fitness for a particular purpose and
all other obligations and liabilities of Vaisala or its
representatives with respect to any defect or deficiency
applicable to or resulting directly or indirectly from the
Products supplied hereunder, which obligations and
liabilities are hereby expressly cancelled and waived.
Vaisala's liability shall under no circumstances exceed
the invoice price of any Product for which a warranty
claim is made, nor shall Vaisala in any circumstances
be liable for lost profits or other consequential loss
whether direct or indirect or for special damages.
VAISALA_______________________________________________________________________ 15
User's Guide ______________________________________________________________________
16 __________________________________________________________________ M210735EN-D
Chapter 2 __________________________________________________________ Product Overview
CHAPTER 2
PRODUCT OVERVIEW
Introduction to Vaisala SPECTRACAP® Oxygen Transmitter OMT355
The following sections provide a short overview of Vaisala
SPECTRACAP® Oxygen Transmitter OMT355 and describes the three
different versions of the product.
Vaisala SPECTRACAP® Oxygen Transmitter OMT355 is an optical
device for measuring oxygen concentration in gases. The instrument
consists of a measurement probe attached to an electronics enclosure.
Typical applications of OMT355 include inert gas generators,
fermentation and composting process monitoring, flue gas monitoring,
inert gas blanketing as well as oxygen deficiency monitoring in
demanding environments.
Oxygen Measurement Range
Vaisala SPECTRACAP® Oxygen Transmitter OMT355 is available
with a measurement range of either 0 ... 25 %O2 or 0 ... 100 %O2. Great
care has been taken to ensure that the devices for measurement of O2
concentrations up to 100 %O2 are manufactured and shipped according
to such cleanliness criteria that the they are compatible with 100 %O
The wetted parts of these devices are cleaned to the necessary standards
.
2
VAISALA_______________________________________________________________________ 17
User's Guide ______________________________________________________________________
and the lubrication materials used in the sealings do not react with
oxygen.
WARNING
Beware of high concentrations of O2: they are highly oxidant/
oxidizing. High O2 concentrations strongly promote combustion and
may react violently with combustible substances.
OMT355 for In-Line and Sampling Cell Mounting
In processes with moderate temperatures (up to 80 °C) and limited
pressures (0.8 ... 1.4 bara), OMT355 can be installed directly into the
process (in-line mounting) using a mounting flange, whereas in
processes with high temperatures (> 80 °C), high pressures (> 1.4 bara)
or extremely difficult mechanical conditions (viscous liquids or slurries,
adhesive materials) an extractive measurement can be made by feeding
a sample of gas into an optional sampling cell.
In in-line and sampling cell configurations the OMT355 transmitter
measures process and sampled O2 concentrations of 0 ... 25 %O2 or
0 ... 100 %O2, depending on the choice of measurement range (see
Oxygen Measurement Range on page 17). With these configurations, it
is assumed that the transmitter housing is mounted in an environment
that has only normal pressure variations and O2 concentration of normal
ambient air, approximately 21 %O2. The environmental conditions of
the electronics housing affect the O2 measurement, because O2
absorption of normal surrounding air inside the enclosure is used for
realizing certain internal functions of the measurement.
Figure 1 and Figure 2 contain the main specifications for the
measurement environment and mounting the OMT355.
18 __________________________________________________________________ M210735EN-D
Chapter 2 __________________________________________________________ Product Overview
0605-001
Figure 1 Flange Mounted Vaisala SPECTRACAP® Oxygen
Transmitter OMT355
0605-002
Figure 2 OMT355 with Sampling Cell
VAISALA_______________________________________________________________________ 19
User's Guide ______________________________________________________________________
Ambient Gas Measurement Version of OMT355
0605-003
Figure 3 OMT355 for Ambient Gas Measurement
Ambient oxygen concentration measurement, for example in oxygen
deficiency monitoring, requires a special version of OMT355. Please
observe that sections of this User's Guide covering the version for
ambient gas measurement are applicable only to customers who have
ordered this specific version of the transmitter.
With the ambient environment configuration it is assumed that the
entire transmitter (both measurement probe and transmitter housing)
is installed in an environment of changing O2 concentration. See Figure
3 on page 20 for an installation environment example.
The ambient environment configuration of OMT355 measures ambient
oxygen concentrations of 2 ... 25 %O2, that is, the main difference
between this version in comparison with the other two is that the
measurement range does not go all the way down to zero percent O2.
There are also differences in operating temperature ranges between
these configurations, see Figures 1-3 and Table 19 on page 156.
To facilitate easy installation on walls, OMT355 for ambient gas
measurement is available with a wall mounting kit.
20 __________________________________________________________________ M210735EN-D
Chapter 3 ______________________________________________________ Functional Description
CHAPTER 3
FUNCTIONAL DESCRIPTION
Measurement Principle and Sensor Technology
The operation of the SPECTRACAP® sensor used in OMT355 is based
on Tunable Diode Laser Absorption Spectroscopy (TDLAS) method. In
this technology the gas concentration is sensed by measuring the
attenuation of a beam of laser light from a tunable diode laser source in
the sample gas. For oxygen sensing the laser wavelength is selected to
match with one of the characteristic absorption lines of oxygen in the
wavelength range of around 760 nm (0.76 μm), in the near infrared
(NIR) region of the electromagnetic spectrum. In the measurement the
diode laser wavelength is continuously modulated to scan across one of
the oxygen absorption lines to generate a periodic signal from a
photodetector, the amplitude of which is proportional to the amount of
oxygen on the path of the laser beam. Figure 4 on page 22 illustrates the
oxygen absorption spectrum and Figure 5 on page 22 the modulation of
the laser wavelength.
VAISALA_______________________________________________________________________ 21
User's Guide ______________________________________________________________________
759 760 761 762 763 764 765 766 767
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
WAVELENGTH (NM)
TRANSMISSION (%, 30 CM)
0512-049
Figure 4 O2 Absorption Spectrum Around the 760 nm Near
Infrared Region
0511-034
Figure 5 Adjacent O2 Absorption Lines and Laser Emission
Peak
22 __________________________________________________________________ M210735EN-D
Chapter 3 ______________________________________________________ Functional Description
Characteristic of the SPECTRACAP® sensor is its inherently good
stability which is obtained due to the continuous reference measurement
built in the measurement algorithm. Furthermore the technology is fast
since no chemical reactions or gas diffusion in sensor materials are
involved - in practice the response time is dictated only by the gas
exchange into the sensor volume and the signal processing time of the
electronics. Furthermore, since the absorption lines of gases are very
narrow and unique by nature, there is no direct cross sensitivity to other
gases in the measurement.
Construction of OMT355 Probe
In OMT355 the SPECTRACAP® sensor has been built into a compact
and robust probe for direct insertion into the measurement location. In
the probe the diode laser light source and the photodetector measuring
the light have been placed behind a protective window, and the light is
directed onto the photodetector using a focusing mirror at the far end of
the probe. Figure 6 on page 23 illustrates the probe design and how the
beam of light goes once back and forth inside the probe.
0511-035
Figure 6 Schematic of Probe Design
The following numbers refer to Figure 6 on page 23:
1 = Light source
2=Mirror
3 = Light detector
The probe is constructed from AISI 316 stainless steel for good
resistance to aggressive chemicals and demanding environments. Other
sample wetted materials are the thin film coating of the optical surfaces
(MgF2 on the lens, SiN on the mirror), and the choice of O-ring
VAISALA_______________________________________________________________________ 23
User's Guide ______________________________________________________________________
material. The probe design incorporates also a Pt1000 temperature
sensor in a stainless steel enclosure for making an on-line temperature
compensation to the measurement, and two heating resistors used to
heat the protective window and the focusing mirror to prevent
condensation on the optical surfaces. The probe is also equipped with a
stainless steel mesh filter (additional porous PTFE filter available as an
option) to prevent dust or particles from entering inside the probe. If this
should nevertheless happen the algorithm used with the
SPECTRACAP® sensor has been designed to minimize the effects of
light obstruction, and even to issue a maintenance warning signal
informing of excessive light loss in the sensor well before the
measurement quality is affected.
Eye Safety
The OMT355 is eye-safe. Laser radiation in OMT355 is emitted
through the laser radiation aperture, as shown in Figure 7 on page 24.
No laser radiation is emitted outside the probe, and in normal conditions
it is not possible to look straight into the laser radiation aperture and
place the eye in the path of the laser beam. Therefore normal handling
and operation of OMT355 is eye-safe. Avoid placing reflective surfaces
(tools, etc.) directly into the probe when the transmitter is in operation,
since this might cause reflection of laser radiation outside the probe.
0611-007
Figure 7 OMT355 Laser Eye Safety
24 __________________________________________________________________ M210735EN-D
Chapter 4 _______________________________________________________________ Installation
CHAPTER 4
INSTALLATION
Selecting Location
The main advantage of OMT355 is its low sensitivity to sample gas
conditions, meaning that the requirements for costly and complicated
sample conditioning systems are minimal. In many applications
OMT355 can be installed directly into the process using a mounting
flange. There is no need for sampling and sample conditioning
equipment. This type of setup also provides a real-time measurement
with no sampling or sample switching delays.
Chemical Tolerance
The OMT355 transmitter contains several O-ring sealings. Two
material options are available for the sealings:
- EPDM (ethylene propylene polymers)
-Kalrez® Spectrum 6375 (perfluoroelastomer with a fluorinated
backbone)
EPDM is the default material, and suitable for a variety of applications.
Kalrez sealings may be used if aggressive solvents or chemicals are
present. Note that Kalrez is not suitable for temperatures below
VAISALA_______________________________________________________________________ 25
User's Guide ______________________________________________________________________
-20 °C (-4 °F). Refer to the table below for chemical tolerance of the
materials with common solvents.
Table 1 Chemical tolerance of sealing materials
Chemical EPDM Kalrez
Acetone Excellent Excellent
Benzene Not recommended Excellent
Butanol Good Excellent
Dietyl ether Not recommended Excellent
Ethanol Excellent Excellent
Ethyl acetate Good Excellent
Isopropanol Excellent Excellent
Methanol Excellent Excellent
Toluene Not recommended Excellent
Xylene Not recommended Excellent
NOTE
If the Kalrez sealings are required, it should be specified when the
transmitter is ordered. Changing the sealings later is work intensive,
and can only be done at Vaisala.
OMT355 Dimensions
In Figure 8 on page 26, all the important dimensions of the Vaisala
SPECTRACAP® Oxygen Transmitter OMT355 are given in mm.
0705-192
Figure 8 OMT355 Dimensions in mm
26 __________________________________________________________________ M210735EN-D
Chapter 4 _______________________________________________________________ Installation
Temperature Conditions of Installation Location
The probe design of OMT355 incorporates a temperature sensor for
making an on-line temperature compensation to the oxygen
measurement. Therefore finding a suitable site for OMT355 is
important for getting representative temperature measurements.
In spite of the low sensitivity to sample gas conditions when installing
OMT355 directly into the process, it is still important to take into
account the differences between the process gas temperature and the
ambient temperature. In this type of installation, the integrated
temperature probe of OMT355 is located inside the process while the
transmitter electronics enclosure remains outside the process. For
operating temperature range of the transmitter, see Table 19 on page
156.
The temperature probe and transmitter enclosure are in contact with
each other via some heat transferring components. Thus, ambient
temperature affects the reading of the temperature probe. This causes
measurement error, because the temperature reading used in the
compensations will be slightly different compared to the actual process
gas temperature.
A location in which the ambient temperature of the transmitter
enclosure is as close to the process temperature as possible minimizes
this effect and vice versa - the smaller the temperature gradient from the
process to the ambient is, the smaller the error will be. Please see Table
17 on page 155 for measurement specifications.
Powerful Light Sources Near the Oxygen Measurement Probe
It is not recommended to install the transmitter in locations where there
is an exceptionally powerful light source in close proximity to the
measurement probe (this only concerns the probe, the transmitter
housing is not affected by light sources).
A powerful light source can interfere with the operation of the light
detector. The interfering effect of a light source depends on the filter
used on the measurement probe and how badly the light is shining into
the measurement probe. The interfering effect is at its worst if no filter
VAISALA_______________________________________________________________________ 27
User's Guide ______________________________________________________________________
is used and the light (for example, sun) is shining directly to the probe
lens or mirror.
Even the stainless steel mesh filter attenuates some ambient light.
Usually it is enough to suppress for example normal indoor or
laboratory universal lighting. More attenuation and better protection
from the effects of exceptionally powerful light sources is provided by
the PTFE filter, which should be used for example outdoors in direct
sunlight.
Maximum Allowed Installation Angle
To prevent liquid from entering the optical path, the drain slots of the
sensor need to be below the optical components' cavities. This limits
installation in high-humidity processes.
For installation in locations of high relative humidity, see Figure 9 on
page 29 for installation angle limitations. If process gas is dry (the
process temperature is much higher than the dewpoint temperature of
the gas) so that there is no risk for condensation, the probe can be tilted
quite freely. However, vertical installation of the measurement probe is
not recommended when using the sampling cell. With a vertically
installed probe and sampling cell, it is possible to encounter some flowdependency when measuring high O2 concentrations.
28 __________________________________________________________________ M210735EN-D
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