Rosemount NGA 2000 Reference Manual-Rev B Manuals & Guides

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Rosemount Analytical NGA 2000

REFERENCE

MANUAL

OTICE

The information contained in this document is subject to change without notice.

Rosemount Analytical's system of NGA 2000 Modular Gas Analyzers and Controllers are patented,

under U.S. Patent 5.787.015.

Excel™, Word™, Visual Basic™, Windows™ and Windows NT™ are trademarks of Microsoft Corporation.

MS-DOS® is a U.S. registered trademark of Microsoft Corporation .

Echelon® is a U.S. registered trademark of Echelon Corporation.

LONTALK™ and LonManager™ are trademarks of Echelon Corporation.

IBM® is a U.S. registered trademark of International Business Machines.

Manual Part Number 748384-B August 1998 Printed in U.S.A.

Rosemount Analytical Inc.

4125 East La Palma Avenue Anaheim, California 92807-1802

ONTENTS

REFACE

PURPOSE/SAFETY SUMMARY ........................................................................P-1

ECTION

1.1 INTRODUCTION ......................................................................................1

1.2 GENERAL INSTRUCTIONS.....................................................................1

1.3 SYSTEM SETUP ......................................................................................2

1.3.1 Basic Instructions........................................................................ 3

1.3.2 Binding ......................................................................................3

1.3.3 Advanced Instructions.................................................................5

1.3.4 Details ......................................................................................6

1.3.5 Troubleshooting .............................................................................8

1.4 ANALYZER MEASUREMENT RANGES.................................................. 9

1.4.1 Basic Instructions........................................................................ 10

1.4.2 Advanced Instructions.................................................................10

1.4.3 Details ......................................................................................11

1.4.4 Troubleshooting ..........................................................................11

NTRODUCTION

1. I

1.3.3.1 Analyzer Power ...........................................................5

1.3.3.2 Naming Analyzers ....................................................... 5

1.3.4.1 TAG.............................................................................6

1.3.4.2 Binding ........................................................................ 7

1.3.4.3 Controller Module Memory Issures .............................7

1.3.4.4 Replacing an Analyzer ................................................8

1.3.4.5 Multiple Control Modules.............................................8

1.4.2.1 To change range fullscale values....................................10

1.4.2.2 To alter the maximum or minimum possible ranges........11

1.5 ZERO AND SPAN GAS SETTINGS .........................................................12

1.5.1 Basic Instructions........................................................................ 12

1.5.2 Advanced Instructions.................................................................12

1.5.3 Details ......................................................................................13

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ECTION

1.6 GENERAL ZERO/SPAN SETUP ............................................................. 13

1.7 ZEROING................................................................................................. 17

1.8 SPANNING ............................................................................................ 22

1. (

1.6.1 Calibrate ranges separately or together ..................................... 14

1.6.2 Calibrate ranges using an Autocal module ................................. 14

1.6.3 Troubleshooting.......................................................................... 15

1.7.1 Basic Instructions ....................................................................... 17

1.7.2 Advanced Instructions ................................................................ 18

1.7.3 Details ..................................................................................... 19

1.7.4 Troubleshooting.......................................................................... 20

1.8.1 Basic Instructions ....................................................................... 22

1.8.2 Advanced Instructions ................................................................ 22

1.8.3 Details ..................................................................................... 23

1.8.4 Troubleshooting.......................................................................... 23

CONTINUED

1.7.1.1 No Autocal Module ..................................................... 17

1.7.1.2 Autocal Module........................................................... 17

1.7.2.1 No Autocal Module ..................................................... 18

1.7.2.2 Autocal Module Present.............................................. 19

1.8.1.1 Set Span Gas Concentration ....................................... 22

1.8.1.2 Perform A Span ........................................................... 22

)

1.9 LINEARIZATION ...................................................................................... 24

1.9.1 Basic Instructions ....................................................................... 25

1.9.2 Advanced Instructions ................................................................ 25

1.9.3 Details ..................................................................................... 26

1.9.4 Troubleshooting.......................................................................... 27

1.10 LINEARIZTION TOUCH-UP................................................................... 28

1.10.1 Basic Instructions ..................................................................... 28

1.10.2 Details ..................................................................................... 29

1.10.3 Troubleshooting........................................................................ 30

1.11 RESPONSE TIME.................................................................................. 30

1.11.1 Basic Instructions ..................................................................... 31

1.11.2 Advanced Instructions .............................................................. 31

1.11.3 Troubleshooting........................................................................ 32

1.12 ANALYZER MODULE HISTORICAL DATA ........................................... 32

1.12.1 Basic Instructions ..................................................................... 33

1.13 ANALYZER ALGORITHM DESCRIPTION............................................. 33

1.14 SECURITY ............................................................................................. 35

1.14.1 Basic Instructions ..................................................................... 35

1.14.2 Troubleshooting........................................................................ 36

1.15 DATE AND TIME ................................................................................... 36

1.15.1 Basic Instructions ..................................................................... 36

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1.16 SCREEN APPEARANCE .......................................................................37

1.17 MANUFACTURING AND SERVICE DATA.............................................38

1.18 ANALYZER STATUS.............................................................................. 38

1.19 ANALYZER INTERNAL DATA STORAGE .............................................40

1.20 SERIAL I/O MODULE.............................................................................42

1.21 NETWORK ISSUES ...............................................................................43

1. (

1.16.1 Basic Instructions......................................................................37

1.18.1 Health (Alarm Status)................................................................38

1.18.2 Analyzer Operational Status .....................................................39

1.18.3 Analyzer Sampling Status .........................................................39

1.18.4 Analyzer Calibration Activity......................................................39

1.18.5 Analyzer Calibration Status.......................................................40

1.18.6 Analyzer Validity Status ............................................................40

1.19.1 Basic Instructions......................................................................41

1.19.2 Details ......................................................................................41

1.19.3 Troubleshooting ........................................................................42

1.20.1 Details ......................................................................................42

1.20.2 Troubleshooting ........................................................................43

1.21.1 LON Data ..................................................................................44

1.21.2 LON Data Details ...................................................................... 44

CONTINUED

)

1.22 MODBUS................................................................................................ 45

1.23 PC LON INTERFACE .............................................................................45

1.23.1 Performance .............................................................................45

1.23.2 Basic Operation ........................................................................46

1.23.3 Details ......................................................................................46

1.23.4 Using Excel with the DDE Server.............................................. 47

1.23.4.1 Basic DDE Points In Excel ........................................ 47

1.23.4.2 Spreadsheet Cell Formula.........................................48

1.23.4.3 To Get An Array Element ..........................................48

1.23.4.4 Reading A Variable ...................................................48

1.23.4.5 Establishing Analyzers Present.................................49

1.23.4.6 Writing To A Variable ................................................50

1.24 AK ......................................................................................................51

1.24.1 AK Example Using The Windows Terminal Emulator ...............51

1.25 ALARM I/O MODULE GENERAL INFORMATION .................................52

1.25.1 Setup Procedure ....................................................................... 52

1.25.1.1 Binding ......................................................................52

1.25.1.2 Setting Up Analog Output..........................................52

1.25.2 Details ......................................................................................52

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iii

ONTENTS

ECTION

1.26 AUTOCALIBRATION MODULES........................................................... 53

1.27 SYNCHRONIZING AUTOCAL MODULES............................................. 55

ECTION

2.1 VERSION 2.2 ........................................................................................... 57

ECTION

3.1 VERSION 2.2 ........................................................................................... 165

PPENDIX

1. (

1.26.1 Troubleshooting.......................................................................... 53

1.26.2 Differences Between The System Autocalibration Module

1.26.3 Use Of The System Autocalibration Module And The Single

1.27.1 Basic Instructions ..................................................................... 55

2. A

3. I/O M

CONTINUED

And The Single Autocalibration Module........................ 54

Autocalibration Module ................................................. 54

)

NALYZER VARIABLES

ODULES VARIABLES

A. G

LOSSARY

NDEX

IGURES

1-1 Typical Menu............................................................................................ 1

1-2 Analyzer Algorithm................................................................................... 33

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

REFACE

URPOSE/SAFETY SUMMARY

This is a reference manual for the NGA series of analyzers. It contains in depth discussion of the various features and operational elements of the analyzers, together with information about their use with computers. It is not intended to be a stand-alone document, but should be combined with the individual analyzer and platform manuals.

A major part of this manual is the description of the NGA variables. These are the names of the packets of information that are communicated over the NGA digital communication network, and are available for external access. It is vital that no attempt be made to directly affect their values without a complete understanding of the results of doing so. Serious damage to the analyzers may result from incorrect assignments.

If this equipment is used in a manner not specified in these instructions, protective systems may be impaired.

DANGER

personal injury, death, or substantial property damage if the warning is ignored.

WARNING

personal injury, death, or substantial property damage if the warning is ignored.

CAUTION

personal injury or property damage if the warning is ignored.

NOTE

important but not hazard-related.

To avoid loss of life, personal injury and damage to this equipment and on-site property, all personnel authorized to install, operate and service this equipment should be thoroughly familiar with and strictly follow the instructions in this manual. Save these instructions.

is used to indicate the presence of a hazard which

is used to indicate installation, operation, or maintenance information which is

will

can

cause

can

severe

minor

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P-1

REFACE

WARNING: ELECTRICAL SHOCK HAZARD

Operate this equipment only when covers are secured. Servicing requires access to live parts which can cause death or serious injury. Refer servicing to qualified personnel.

For safety and proper performance, this module must be connected to a properly grounded three-wire source of electrical power.

WARNING: POSSIBLE EXPLOSION HAZARD

This equipment may contain modules used in the analysis of sample gases which may be flammable. If used for analysis of such gases, the module must be protected by a continuous dilution purge system in accordance with Standard ANSI/NFPA 496-1993, Chapter 6.

WARNING: POSSIBLE HAND INJURY

Do not place hands or fingers in Platform front handles when the front panel is open. Dropping front panel while hand or fingers are inside either handle can cause serious injury.

WARNING: PARTS INTEGRITY

Tampering with or unauthorized substitution of components may adversely affect safety of this product. Use only factory approved components for repair.

P-2

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

NTRODUCTION

1.1 INTRODUCTION

This manual provides detailed general information about the operation of the NGA system. It is intended for the serious user or system integrator, or those writing software that interfaces directly with the system.

Sections are arranged in a how-to fashion, each chapter normally having a basic, advanced, detailed, and troubleshooting section.

Basic sections give the essential operational procedure

•

Advanced gives the complete procedure for analyzer experts

•

Details shows the inner workings of the analyzer

•

Troubleshooting gives some suggestions to help resolve problems

•

Some sections are not formally split in this fashion

•

This manual is intended to be used with the Platform manual, and also with each individual analyzer manual, such as those for the CLD, FID, NDIR and PMD analyzer modules.

1.2 GENERAL INSTRUCTIONS

Main Menu

Basic controls . . .

Expert controls and set up . . . (Operational configuration)

Technical level configuration . . . (Diagnostic and manufacturing/service)

DISPLAY PARMS. NEXT LOCK INFO

IGURE

1-1. T

YPICAL MENU

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INTRODUCTION

The NGA menus have three separate paths, called These paths are setup so as to separate the functions of the three main varieties of personnel expected to use the analyzer systems, that is Operators, Engineers and Maintenance Technicians. The security system outlined below is designed to restrict access in this manner.

Basic menus allow an operator to perform the normal, simple analyzer functions such as zeroing, spanning and changing ranges.

The expert menus allow an expert analyzer user to configure the analyzer as he desires, and to perform the more advanced controls, as well as perform the basic controls with more information and options allowed.

The technical menus provide control over the system operation, and access to the manufacturing data, the service data and the diagnostic data.

These menus are found under the main three choices in the

In normal operation, the control module screen shows either a single analyzer display, or the multiple analyzer display. From the latter you can select a single analyzer to examine, by pressing the "SELECT" key twice.

basic, expert

Main menu

and

technical

From the single analyzer display you can either select the menus by pressing the "'MENUS" softkey, or you can select a couple of screens that provide basic essential information about the analyzer. Access these by pressing the "PARMS" (short for parameters) softkey.

If you press the "MENUS" softkey, you will enter the menus, has five softkeys labeled at its foot. In all menus other than this one (with a few unintentional exceptions!) the button in the bottom left hand comer will jump you to the

Main menu

screen for the menu you are on.

. The button in the bottom right hand corner will jump you into the help

Main menu

. This menu, like all

1.3 SYSTEM SETUP

The usual NGA system consists of a control module, one or more analyzer modules, and one or more I/O modules. If you have only the one analyzer module, the system will set itself up automatically, but if you have more than one you will have to give it some instructions as to how to configure itself. In particular, you have to tell it which analyzers are connected to which I/O modules.

If you have no I/O modules,. you can skip this section.

If you have more than one control module in a system, whether or not you have more than one display in it, you will need to read the advanced section here.

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

NTRODUCTION

1.3.1 B

ASIC INSTRUCTIONS

Verify you have all the modules you are going to use, and that they are all connected to the power supplies, and to the LON. Power connections are normally made through the three pin connector on the front of each analyzer module, or through the audio connector on the back of the platforms. You can power a single analyzer from the internal power supply in a platform, but if you have more than one analyzer you will need some sort of additional power supply, such as the 24V, 30 amp Bulk Power Supply made by Rosemount Analytical. Each analyzer draws about 5 amps, so a 30 amp supply can handle about five analyzers.

WARNING: IMPROPER CONNECTION

The internal LON connection in the platform is for use with internally mounted and powered analyzers only. Using this connection for external analyzers or LON components could result in short-circuiting the 24V power supply through the cable, with resultant damage.

1.3.2 B

INDING

You have to tell the system which I/O module is bound to which analyzer.

ERSION

Verify that all the analyzers and I/O modules are present:

Enter the

Enter Technical level configuration...

Enter Listing of all modules...

Verify they are all there. (Note that system Autocal modules are listed as five separate modules.)

Enter the

Select Technical level configuration...

Select System setup..

Select Module binding...

2.2

CONTROL MODULES

Main menu

(press "HOME" or "MENUS")

Verify that the analyzer listed on the

If it isn't, select the

Analyzer module selected

748384-B Rosemount Analytical August 1998

View bindings...

: line.

Analyzer module selected

. press "NEXT" until the desired analyzer is shown on

: line is the correct one.

NGA Reference Manual

INTRODUCTION

Press the left arrow key to return to the

Select the desired module. You will jump back to the previous menu.

Check that the I/O module selected is correct for the analyzer shown - NOT the analyzer at the very top of the screen!

Press "BIND".

Wait while the system restarts, and then re-enter the binding menu.

Repeat the procedure for each I/O module until all are bound.

Note: If you have made a mistake, press "UNBIND". Then repeat the binding procedure.

ERSION

Verify that all the analyzers and I/O modules are present:

Enter Listing of all modules...

2.3

CONTROL MODULES

Module binding

Verify they are all there. (Note that system Autocal modules are listed as five separate modules.)

Enter the

Select Technical level configuration...

Select System setup..

Select Module binding..

Note that each analyzer is listed on this screen. For each in turn, select the analyzer.

Press the right arrow key.

Select, from the list of I/O modules shown, one module to be bound to the analyzer.

Press the ENTER key. Continue until all desired I/O modules are selected.

Press the BIND softkey.

Verify that all the analyzers and I/O modules are present.

Main menu

(press "HOME" or “MENUS”).

Note: To unbind particular I/O modules, select them in the Module binding menu, and press UNBIND.

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

NTRODUCTION

1.3.3 A

DVANCED INSTRUCTIONS

1.3.3.1 A

The quality of the analyzer power is important. It must be within a couple of volts of 24 V, and it must be reasonably quiet. 100 mV of noise is adequate. Earlier analyzers required inrush current limiting if the leads supplying power were longer than a couple of feet. Later analyzers (with the CE mark) were not as touchy. If such protection was not provided, the analyzers might blow fuses upon start up. In this case, replace the fuse and try again. Don't plug in the analyzer power while it is turned on.

1.3.3.2 N

Verify the I/O modules are named appropriately. You want to be able to tell which I/O module is which, so you can bind it to the appropriate analyzer. The variable TAG is used for this. Later I/O modules are able to tell which slot they are plugged into on the control module Backplane, but most I/O modules cannot do this, and so they rely on your knowing which one they are in some other way.

An easy way to do this is as follows:

Plug the I/O modules into the platform one by one. Do this with no analyzers connected.

NALYZER POWER

AMING ANALYZERS

Power up the Platform.

Press the button marked "RE-INIT" as the control module initializes itself.

When it is showing its main display, press the button marked "MENUS".

Select

In the resulting menu, select

Select the listed I/O module.

On the bottom line of the resulting menu edit the I/O module tag to something that you will recognize.

Do this for each I/O module in turn. Then reconnect the whole system, including the analyzers, and again press the “RE-INIT” button.

Verify you know which analyzer is which. Normally this is easy, but if you have several examples of the same kind of analyzer, you will need to verify they are named appropriately.

You can do this even though all the analyzers are hooked up at once, since you can look at them and see what their serial numbers are.

Technical level configuration...

Listing of all modules...

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NGA Reference Manual

INTRODUCTION

From the main screen, press "MENUS"

Select

Select Analyzer module data. Read Analyzer module s/n: and determine which analyzer you are looking at.

Edit the the heading on the top of the screen for the analyzer you are looking at. This line won't change until you enter another menu, but the analyzer will remember whatever you enter, up to 31 characters.

Press "HOME".

Press "NEXT" (it selects the next analyzer in its list.).

Repeat the procedure for the new analyzer.

An alternative is to start the Rosemount Analytical DDE server program in a PC connected to the system. When it has completed its network interrogation, open the DDE server program icon and click on "File". Select "Nodelist". Click on each module's TAG in turn, and edit them as you like. Then exit and restart the DDE server before attempting to use any application with it.

Technical level configuration

Service menus...

Manufacturing data...

User tag number:

line to make the tag whatever you want it to be. The tag is

...

1.3.4 D

ETAILS

1.3.4.1 TAG V

All modules use the variable called TAG to contain their name. Modules also have a node name, and a program id, and these are used internally in the LON. They are not normally accessible externally, though both may be used by non-NGA LON nodes such as a PC setup to monitor the NGA system.

Analyzer Modules also have a serial number in their variable AMSN. This should match the serial number assigned to the analyzer and visible on a label on their sides.

The control module puts the contents of TAG onto the main display screens, and also onto the top line of the menu screens. It regards menus as belonging to an analyzer, the one selected in the main screen or selected by pressing the NEXT button in higher level menus. The TAG and the present time reading are always displayed on the top line of every menu screen.

ARIABLE

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

NTRODUCTION

Note

TAGs should be kept as short as possible, and should not contain blanks, dashes or other mathematical signs. This will avoid problems when using a PC to interface with the module.

The gas measured is shown in the variable GAS. This is normally straightforward, but in the case of the FID you should verify that this variable is matched with the response factor, whether the analyzer is measuring in C1 or C3 (methane or propane) units, for example.

The analyzer sensitivity is described in coded form in its bench code (AMBC). Particularly in the case of NDIR analyzers, the bench has to be setup for the analysis desired.

Individual analyzers may also have internal serial numbers reported in other variables visible in their

Network variables: TAG, AMSN, AMBC, GAS, CARBON_ATOMS.

Manufacturing data screen.

1.3.4.2 B

Binding is the process of connecting various variables in the analyzer module with equivalent variables in the I/O modules. Normally the LON expects to bind individual variables, but the NGA system simplifies this by binding whole groups of them at once. Once they are bound, an update to one variable on one node will automatically cause the variable bound to it on another node to be updated as well. This allows the I/O module to track the main reading (PVA) of the analyzer automatically, and it allows the I/O module to change the range of the analyzer by updating its CRANGE0 variable, thus changing the analyzer's CRANGE variable which is bound to CRANGE0.

Subsequent revisions of the control module software (from V2.3) will allow you to bind all the I/O modules at once, rather than making you bind each one, waiting for the system to reset between each module.

Binding is only necessary for systems with I/O modules. Systems that have no control module, and which rely on a computer to get data from analyzers, do not need to do any binding.

1.3.4.3 C

The control module has a restricted amount of memory, just as do all computers. It can therefore handle only a certain number of analyzers and I/O modules. It stores all of the data from each module within itself. If an analyzer module is removed and replaced, the control module will remember the data from the analyzer, so if the analyzer is replaced the control module can recognize it and bring it back on line immediately. However this also means that the control module will remember all the

INDING

ONTROLLER MODULE MEMORY ISSUES

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INTRODUCTION

analyzers it has ever seen, so that it will eventually run out of memory. The limit with a V2.2 control module is about 6 analyzers. With a V3.0 control module it is 15 analyzers.

1.3.4.4 R

If you replace an analyzer with a new one, you will have to reset the control module so that it can recognize the new analyzer. If you run out of memory in the process, the control module may hang and not complete the initialization. In this case, press the "RE-INIT" button and rebind all the I/O module all over again. If the control module is so lost that the "RE-INIT" button doesn't work, remove power from it briefly and replace the power, and then press the "RE-INIT" button as soon as it appears. Then go through the binding process again.

This procedure should be improved with the V3.0 control module software.

1.3.4.5 M

In V3.1 or earlier, it is not possible to connect more than one control module on a system. If it is desired to connect them to a single computer, it is necessary to use "Routers" (a component sold by Echelon Corporation) to isolate the control modules from each other.

1.3.5 T

ROUBLESHOOTING

EPLACING AN ANALYZER

ULTIPLE CONTROL MODULES

Control module hangs up during a reset…

Control module out of memory. Press "RE-INIT" button, or remove power, replace power and then press "RE-INIT" button.

You may have several analyzers updating their readings as fast as they can, saturating the network. In this case, only connect up one at once, and when it comes up, set its LON update rate to 10 per second or once per second. See "Response time" below. Then hook them all back up and try again. Don't forget to remove the I/O modules while you do this - if they were not already bound, they will all bind themselves to the first analyzer you try this with.

"RE-INIT" button doesn't work…

Control module crashed. Remove power, replace power, then press "RE-INIT" again.

Even after power up, "RE-INIT" button doesn't work…

Battery backed RAM is corrupted. Open the control module, remove the jumper next to the battery (the cylindrical object above the board at the near end - the jumper is

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

NTRODUCTION

just next to the positive end's wire connection to the board); wait for two minutes, replace the jumper and replace the board in the control module. Then press "RE-INIT" when power comes up.

I/O doesn't respond to the analyzer signals…

The I/O modules aren't bound. This happens after a "RE-INIT". Don't press this button unless you mean it! You have to go through the binding procedure again. You may have bound all the I/O modules to one analyzer by powering the system up with only one analyzer connected, but all the I/O's connected. If so, press the "RE-INIT" button and start again. The LON may be saturated. Try reducing the LON update rate of all the analyzers to 10 per second. After a short time the I/O modules should respond once again.

Several I/O's have the same name…

New I/O modules are all called the same thing. In order to tell the difference between them, you have to name them. See the procedure earlier in this.

Later I/O modules can tell which slot they are plugged into. You can use this information to identify them. It is located in the same place as the I/O tag name, under "Listing of all modules.."

1.4 ANALYZER MEASUREMENT RANGES

NGA analyzer modules have four ranges available. These ranges normally do not correspond to any physical settings in the analyzer, they are there for operator convenience. It is possible to separately zero, span and linearize each range, in which case you may well not get the same reading on a given gas, if you change the operational range. Some analyzers do change an internal setting on a range change, though they never do this dynamically based on the signal within a range. If they do this, or if the filtering time is set to a value greater than zero, there will normally be a short term "glitch" as the analyzer reaches its new value.

The dynamic range of the analyzer on a single range is normally quite great, and it is often only necessary to change ranges if you are recording the analog output of the I/O module. However for traditional reasons some users like- to operate between 20% and 80% of a range, and thus change ranges anyway, even though this makes no actual difference to the analyzer's operation or resolution.

It is possible to set the I/O module to produce an output independently of the analyzer's current range. You can make the I/O module stay on a particular range, regardless of the analyzer, or you can make the analyzer stay on a particular range and force the I/O to change its ranges in response to a remote (digital line) command. You can connect two or more I/O's to a single analyzer, and make them respond to different analyzer ranges, thus getting two simultaneous outputs, one for low range

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INTRODUCTION

resolution, and the other for upset conditions.

If you make the I/O operate independently of the analyzer, it will change its output range within about 120 micro seconds of a remote command (for an I/O with a 5 MHz clock, later I/O's with a 10 MHz clock respond within 80 micro seconds). There is no "glitch" at all in this case, since the analyzer is not affected by the range change request.

If the I/O has to make the analyzer range change, the total transaction may take up to half a second, and there may be a glitch in this time.

In general the only reason for making a real range change is to use a different linearizer curve on a lower signal. It may also be useful to get a better signal to noise ratio if the range change is drastic, such as changing from 0 - 10,000 ppm. to 0 - 10 ppm on a FID. On the former range the resolution is about 0.1 ppm, whereas on the latter it is about 0.01 ppm.

1.4.1 B

1.4.2 A

ASIC INSTRUCTIONS

1. Enter the

2. Select

3. Edit the

DVANCED INSTRUCTIONS

1.4.2.1 T

1. Enter the

2. Select

3. Select Analyzer module setup.

4. Select

5. Select

Main menu

Basic controls...

Measurement range number:

O CHANGE RANGE FULLSCALE VALUES

Main menu

Expert controls and setup

Gas measurement parameter

Range setting

line

s..

s.. .

6. Edit the range upper and lower setpoints as desired.

7. Press the left arrow key.

8. Select

9. Edit any linearization parameters you have to due to the range change, such as which linearizer is used on which range, or what the linearization coefficients are.

Linearization parameters

...

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NTRODUCTION

1.4.2.2 T

1. Press "HOME" or enter the

2. Select

3. Select

4. Select

5. Select

6. Edit the minimum and maximum ranges as desired.

1.4.3 D

ETAILS

The analyzer won't let you edit the fullscale range to a value higher than the maximum range, or lower than the minimum range. Outside these bounds the analyzer won't meet its specifications, probably. Only edit these if you have made a hardware change to the analyzer so that it can now cover a new range.

If you increase a range by more than 10% without changing the linearizer range, the analyzer will disable that linearizer. However, don't simply increase the linearizer range to avoid this - the coefficients must be changed as well, or you will have linearity errors.

O ALTER THE MAXIMUM OR MINIMUM POSSIBLE RANGES

Main menu

Technical level configuration

Service menus...

Manufacturing data...

Analyzer module data.

...

Any bound I/O module will get its ranges from the analyzer, you don't have to change them in the I/O module as well.

Network variables: RNGHI, RNGLO, CRANGE, CURRENTRNGHI, CURRENTRNGLO, MAXRANGE, MINMANGE, LINRNGHI, LINA0_, LINA1_, LINA2_, LINA3_, LINA4_

1.4.4 T

ROUBLESHOOTING

I changed a range and now my linearity is wrong…

You have to change the linearizer parameters if you change a range value. You can't use a linearizer that covers less than 90% of the range you axe on. Either select the linearizer from the next higher range, or re-linearize the present range.

It won't let me make the range bigger (or smaller)…

You have reached the editing limits set by the minimum range or the maximum range. You probably should not be setting the ranges outside of these limits. If you have made a physical change to the analyzer, or you are willing to live with the lower

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INTRODUCTION

specifications, you can edit the minimum or maximum ranges in the

screen.

data

Manufacturing

1.5 ZERO AND SPAN GAS SETTINGS

It is essential that the zero and span gases are correctly described to the analyzer. It zeros and spans by making the reading it is getting from its measurement signal equal to what it has been told is the zero or span gas value. If it is zeroing or spanning ranges separately it may well produce bogus answers if the zero or span gases are entered incorrectly.

Zero and span gas values are entered into the Calibration gases menu under Expert controls and setup.

1.5.1 B

ASIC INSTRUCTIONS

Select the analyzer you want to zero.

Press "MENUS" or "HOME" to enter the

Select Expert controls and setup

Select Analyzer module setup…

Main menu

Select Calibration gas list…

Edit the zero and span gases until they refer to the values on the bottles.

Press "HOME" to return to the

1.5.2 A

DVANCED INSTRUCTIONS

Zero gases are normally simply of zero concentration, but in some cases it is desirable to "zero" off a non-zero gas. In this case, it may be necessary to iterate between zero and spanning a few times until the results are accurate enough.

Gas cylinders are notoriously inaccurate. Even when they are specified at ±2% certified accuracy, you can still have considerable errors. Some users prefer to zero and span off gases of mediocre quality, but to "name" the gases by comparison with a known high precision reference gas. In this case, carefully zero and span the analyzer on the reference gas, and then measure the "span" gas with the analyzer. Enter the result as the span gas "name" both on the bottle and in the it is time to replace this bottle, "name" the replacement in the same way.

The span value has to be between 20% and 110% of the fullscale range. Ideally it should be about 80% of the range.

Main menu

Calibration gas list

. When

The FID analyzer can be set to be calibrated on various kinds of hydrocarbons, such as methane or propane. Its response factor must be adjusted accordingly. On the same

Calibration gas list

screen, the FID includes a line marked

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

Calibration gas HC

NTRODUCTION

response factor:.

propane. The analyzer will then regard the span concentration as referring to that kind of gas.

1.5.3 D

ETAILS

The analyzer compares its reading on the span or zero gas with the value entered into the

Calibration gas list

zero and span factors so as to make its reading correspond to the value entered as the span or zero gas concentration. It is therefore vital that the value entered be correct.

The

Calibration gas list

away from the lower skilled operators. Entry of an incorrect value will completely invalidate the analyzer's readings thereafter.

Network variables: SPANGAS, ZEROGAS, NOSPANGAS, NOXSPANGAS, ZERO, SPAN, CARBON_ATOMS, NO_NOX

Edit this to the desired response factor, 1 for methane, 3.14 or so for

value for the range it happens to be on. It adjusts its internal

is located under the

Expert controls

menu so as to keep it

1.6 GENERAL ZERO/SPAN SETUP

During a zero or span the analyzer reads the signal from the gas detector, calculates the apparent gas level, compares it with the desired level as entered in the

gas list

error value of the desired value. The error is 0.02% of the upper range value.

During the calibration sequence the analyzer monitors the reading over a period of time set by the CALTIME variable, located in the

under Analyzer Module setup .... If it detects a drift of the reading, it will wait for a

longer time until the reading is stable, or until the time out period set by CALTIMEOUT, also located in the normally set at about 2 minutes. The analyzer will perform its zero or span anyway at the end of the timeout time.

If the gas value is wrong, or the analyzer has drifted excessively, the analyzer will check the reading on the calibration gas against the named value in the

gas list

analyzer is set to ignore limit checking, it will calibrate anyway, unless the span gas value is outside the allowed range of 20% - 110% of the range value.

You can select whether to zero or span all the ranges together or separately. If you make them separate, unless this is the first time that this analyzer has ever been calibrated, it will only zero or span the range that you are on. Other ranges will not be affected. If you elect to zero or span them together, the results will depend on the gas values and the range values already set in the analyzer.

, and modifies the internal calibration factors until the reading is within a small

Calibration parameters.

Calibration parameters

, and if it is set to check its limits, it will not calibrate. Conversely, if the

menu as Calibration time out: This value is

Calibration

screen

Calibration

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If the ranges are all zero based, and the zero gas is of zero concentration, the analyzer will have no difficulty zeroing all the ranges at once. It does this by changing the range to range 1, zeroing it, changing to range 2, waiting for stability and zeroing that, and so on.

When it tries to span the ranges, if the span gas is above 10% and below I/O% of the range value on any range, it will span that range, but if not it will not perform a span. Thus if the span gas is 900 ppm, and the ranges are 10, 100, 1000 and 10,000 ppm, and you are on range 3 (0 - 1000 ppm), it will only span range 3, even if you tell it to span all the ranges together. In general, with widely spaced ranges such as this example, it is best or indeed essential to span the ranges separately.

Bear in mind that the NGA analyzers have very good linearity and dynamic range, and it is normally quite practical to operate them over a dynamic range of 30:1 or more on a single range, if you are using a digital output.

1.6.1 C

1.6.2 C

ALIBRATE RANGES SEPARATELY OR TOGETHER

From the

Select

Edit the zero and span calibration lines as desired.

There are two Autocal modules available for the NGA systems (other than the on-stack sample control module). One of them is designed to work with a single analyzer, and to calibrate individually its separate ranges, the other is designed to work with up to four analyzers, providing up to four span gases to span any number of analyzer ranges. You can set these modules up to zero and span the analyzers on a timed basis, and you can make them perform a zero or span or both at will. You achieve the latter by entering their control screen, under then setup the module to zero and span as you desire, you can simply press the "START" button and it will put the gases on the analyzer(s), wait the appropriate time, zero them and span them. It is a common error to assume that the analyzer basic controls "ZERO" and "SPAN" buttons will make this happen - it won't, you have to control them from the auxiliary module controls as described above. A future version (post V2.2) of software will rectify this automatically. See the Autocal module manuals for details on how to set them up.

Main menu

Expert controls and setup

Analyzer module setup

Calibration parameters

ALIBRATE RANGES USING AN AUTOCAL MODULE

Auxiliary module controls

Expert controls and setup

.. ., then select the Autocal module. If you have already

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NTRODUCTION

Network variables: CALTIME, CALTIMEOUT, ZERO, SPAN, AMFN, CALCHKLIMITS, ZERORNGS, CALRANGES, CALFAIL, CALFPC

1.6.3 T

ROUBLESHOOTING

Analyzer will not zero…

Verify you have a real zero gas; verify that the zero gas in the to whatever the zero gas really is.

See the line marked

If the analyzer has been changed in some way, so that its zero reading is quite different from what it should be, verify that the limits checking is turned off in the

Calibration parameters

Verify the limits checked for are reasonable in the

If all else fails, get into the

Expert analyzer controls...,

for the range you are using. You can read the raw signal for the zero gas at the bottom of this screen. If you edit the signal, you will effectively zero the analyzer.

Result..

menu in the Expert controls section under Zero/span calibration. The

Result of last zero

menu. Zero it, then turn the limits checking back on.

: should give you a hint as to what happened.

Calibration parameters

Factors

"CAL" softkey, "FACTORS" softkey, and then select factors

menu. Find this under

Zero factor:

number to be the same as the raw

Calibration gas list

menu.

Expert controls and setup,

is set

You can see what the stored zero and span factors were by pressing the softkey marked "HISTORY". If desired, you can load the stored or the manufacturing values into the current values by pressing one or other of the two RSTR ... softkeys. This will at least bring the analyzer back to the calibration factors it used to have. When you are satisfied that you do have a good calibration, you can store the values into the

Stored values

If you have made a large span change, the zero may be offset excessively. In this case simply redo the zero and span again.

variables by pressing the "STORE" button on the factors screen.

Analyzer will not span correctly…

See the details.

The values of the span gases must be entered correctly. See the discussion elsewhere about errors in span gas bottle naming. It is easy to replace a span gas bottle, but to forget to enter the new span gas values, and therefore to get an inaccurate span. You can guard against this to some degree by enabling the

Analyzer will not zero

paragraph above. In addition, there are a few additional

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calibration error checking, and setting the failure margin to a low enough value to avoid the worst mistakes. However this may mean that the analyzer will not be able to calibrate itself due to normal drifts, temperature excursions etc.

If the analyzer has excessive noise, it may not span to the correct number. In this case it is necessary to troubleshoot the analyzer itself.

The fullscale range value must be within 90% to 110% of the linearization range value, or the linearizer will not be allowed to apply. In this case, the span may be wrong. Also the linearizer curve must be monotonic between -5% and +110% of the fullscale range.

The analyzer will not span at all…

The span gas value must be within 20% to 110% of the fullscale range value. If it is outside these limits, the analyzer will simply not span. Change the fullscale range value, or the span gas value if that is wrong, so that you are within these limits.

The calibration limits are enabled, and the span drift is greater than that allowed. Disable the limits and try again, or make the limits wider and try again.

You expect the Autocal module to put a span gas on the analyzer, but you have pressed the SPAN button in the controls the analyzer, it doesn't control the Autocal module. If you press it, you have to verify the gas is present first! If you want to use the Autocal module to control the gas flow, you have to get into the Autocal module control screen under Expert controls, then auxiliary module controls.

Basic controls

screen. The Basic controls screen only

One range calibrates, but others don't…

You are probably trying to span all ranges together when the analyzer cannot do it. Set the analyzer to span ranges separately, and span each range on its own span gas. Alternatively, if you only want to operate on one range, set all the ranges to the same fullscale value, then it won't matter which range you are on and you can span them all together.

Nothing seems to work, I'm lost…

We have put a back-up, fail-safe into the design. There are enough settings and special circumstances that it is quite possible for both you and the analyzer to get confused, particularly if you have modified the analyzer hardware or software in some way.

The first back up is to put the last stored calibration factors back into the present ones, by getting into the "Range (n) factors" screen for the range you are on, and then getting into the "HISTORY" screen. Press "RSTR ST" to put the last good factors into

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

the present set. Alternatively you can restore the manufacturing factors with "RSTR MN".

This won't do you much good perhaps if you have changed the hardware, since the conditions may be very different now. In this case, you can get into the factors screen for the range you are on, and manually edit the factors on zero gas (edit the zero factor) and span gas (edit the span factor). Usually, you can just make the reading approximately right, and then do a zero or span using the softkeys in the calibration screen.

1.7 ZEROING

Zeroing is the function of adjusting the analyzer's offset so that when given a zero gas, it reads zero, no matter how the analyzer span is set. By extension this includes adjusting the low end of a suppressed range, although in this case the span setting will have an effect on the low end reading.

NTRODUCTION

1.7.1 B

ASIC INSTRUCTIONS

1.7.1.1 NO A

Select the analyzer you want to zero.

Flow zero gas through the analyzer.

Press "MENUS" or "HOME" to enter the

Select

When it is stable, press "ZERO".

Press "ZERO again on the "

Press "HOME" to get back to the

Basic controls...

1.7.1.2 A

Select the analyzer you want to zero.

UTOCAL MODULE

Are you sure?"

UTOCAL MODULE

Main menu

screen.

Main menu

Press "MENUS" or "HOME" to enter the

Select

Select the Autocal module, whatever you have called it.

748384-B Rosemount Analytical August 1998

Expert controls and setup

Auxiliary module controls...

Main menu

NGA Reference Manual

INTRODUCTION

Either do a complete auto-calibration from the first screen that appears (by pressing

"START"), or

Select

Set the

Select the correct range to zero with

Select CAL in the

Press "START".

You can press "ABORT" to abort the calibration, and then press it again to cut short

1.7.2 A

1.7.2.1 NO A

Select the analyzer you want to zero.

Flow zero gas through the analyzer.

Enter the

Manual calibration function...

Gas to be used for calibration:

Calibration or QC check:

the sample purge time if you want.

DVANCED INSTRUCTIONS

UTOCAL MODULE

Main menu

to "Zero gas".

Measurement range number:

line.

Select

Select the range you want to zero.

Verify gas flow.

Press CAL or select

Press "ZERO".

Press "ZERO" again.

Press the left arrow.

Select

Examine the

If desired, press the left arrow key to return to the calibration screen.

Expert controls and setup

Expert analyzer controls...

Zero/span calibration...

Result…

Calibration results

screen to see how well you did.

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NTRODUCTION

Press "FACTORS".

Select the calibration factors for the range you are on.

View the factors, and if desired, edit the "Zero factor" to the raw signal number shown on the bottom of the screen. This will produce a zero output on the gas you have flowing.

1.7.2.2 A

Select the analyzer you want to zero.

Enter the

Select

If you have not configured the Autocal module, do so.

Select

Press "START".

Alternatively, select

Select the gas desired, the range desired and the operation desired, then press "START".

1.7.3 D

ETAILS

Certain analyzers can take a long time to get a good zero reading. If the analyzer has been exposed to a high level gas, it may take many time constants to get down to zero again. This means that you should be careful about doing a "Zero - span - zero" check: the analyzer may not read the same thing on the second zero, simply because it has not had a chance to get back to it. The NGA analyzers are capable of reading gases with a great deal of precision, so you can easily see if the zero reading is not correct, and this can be confusing.

UTOCAL MODULE PRESENT

Main menu

Expert controls and setup

Auxiliary module controls...

Manual calibration...

Two kinds of analyzer are particularly prone to zero problems. FID analyzer measure hydrocarbons, and they are more responsive to high molecular weight hydrocarbons than anything else. Oils, in particular, produce high readings due to the large size of the molecules. If there are oils or other high molecular weight hydrocarbons in the sample system, they will stick to the sample tubing walls and take a very long time indeed to evaporate away. If you expose the analyzer to a really high concentration of such materials, such as by spilling gasoline near the sample intake, you may have to disassemble it and clean all the plumbing before it will read a good zero again.

The symptom of hydrocarbon contamination is that the analyzer reads high on zero

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INTRODUCTION

gas, and this reading very slowly decays over a matter of weeks. You can speed up the process by cleaning out the tubing with alcohol and distilled water, or by flowing argon through it while heating the tubing to red heat with a flame. Needless to say, this should not be done to Teflon tubing! You should use stainless steel components and tubing, and the tubing should be cleaned before use. Otherwise, if you do use Teflon or copper tubing, and you do not take precautions, you will suffer from this bleeding down effect for a long time.

Trace oxygen and water vapor analyzers have similar zero problems. Both water vapor and oxygen are present in the air at very high vapor pressures, and thus will leak or diffuse into sample systems with great ease. Water vapor will stick to walls even worse than hydrocarbons do, and may take many weeks to be removed. Both water and oxygen will readily diffuse through any plastic components, and you will not be able to reach levels around 1 ppm unless you make the entire sample system out of stainless steel, including valve and regulator diaphragms. Even when you have made the sample system perfect, you will find that getting down to sub 1 ppm levels may take several days. After exposure to air for a short time, for example while replacing a sensor, the system may take a day to come back to zero.

For these reasons, zeroing trace analyzers is not an easy thing to do. If you go ahead and zero them anyway, you may find that you get negative readings as the sample system cleans out, and your readings around the zero point may be quite unreliable.

Trace levels around the 10 ppm value are normally comparatively unaffected by the above considerations, unless you have made a gross error in the sampling system. You should take the above warnings very seriously if you are trying to measure in the I ppm or less band.

If you think that you are not getting good results at these low levels, the reasons are almost invariably due to sample contamination. Make sure you rule out any possible sources of contamination before deciding that you have an analyzer problem.

Network variables: CALTIME, CALTIMEOUT, ZERO, SPAN, AMFN, CALCHKLIMITS, ZERORNGS, CALRANGES, CALFAIL, CALFPC

1.7.4 T

ROUBLESHOOTING

Zero drifts down over time…

If a FID, or trace 02, analyzer, you have sample contamination. In the case of the FID, you must determine where the contamination is coming from, possibly by connecting zero gas directly to the sample inlet, using new ultra-cleaned stainless steel tubing, and verify that the analyzer itself is not contaminated. If it is, it will clean itself out in time if you leave it, but if this is not practical, you have to send it back to the factory for disassembly and cleaning. Otherwise, replace your tubing with stainless steel, and

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NTRODUCTION

clean all the sample components, preferably with a blow torch while flowing argon gas through it.

For oxygen analyzers, an elevated zero means a leak. Remember that oxygen diffuses through any kind of plastic. Also remember that it is the partial pressure difference that controls the diffusion rate - the fact that your sample is at 3000 psig means nothing to the oxygen atoms. To them, a bottle of pure nitrogen is a vacuum, and they whistle into it if given a chance. It is normal for an oxygen analyzer to take a day or two to come to a good zero reading, leave it for a while and see if it stabilizes before worrying.

You can test for leaks by shutting the sample flow off both upstream (first!) and downstream of the analyzer. The oxygen reading should stabilize at a low level of a ppm or so, if it goes up to a significant level you have a leak.

After a zero, the reading is very erratic…

Put a span gas in and see what it reads. If you have spanned on a zero gas, with the calibration limits disabled, you will have made the span setting much too sensitive. In this case, verify you do indeed have span gas in the analyzer, and span it again (disabling the limit checking first), then zero it again.

Similarly, if you have zeroed with a span gas, zero it with a real zero gas and re-span, then zero again. Now enable the limit checking so this doesn't happen again.

It refuses to zero…

Verify you do have a real zero gas in the analyzer, and disable limit checking. Then zero it again. Also, zero on all ranges independently.

After a span, it won't go back to zero…

Leave it on zero gas for a long time, at least a hundred times the response time of the analyzer. See if it made it back to zero again. If not, check for leaks of span gas into the zero gas. If the zero is now lower than it was before, i.e. negative, re-zero and then re-span. If it is higher, and the previous zero happened within a few minutes, something is wrong with the zero gas, the sample system, or possibly the analyzer. If the analyzer temperature has changed, such as by opening a door and allowing cold or hot outside air to blow on the analyzer, let its temperature stabilize again and try again.

It may be that the analyzer span is now very different from before. Check your span gas for correctness, and that you did indeed have flow of gas during the span. If all is well, re-zero and then re-span.

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1.8 SPANNING

Spanning is the function of adjusting an analyzer's measurement gain such that a near fullscale gas reads correctly. Since this reading depends on the zero, it is essential that you perform a zero before a span. It is also essential that you verify that the span gas value has been entered correctly in the calibration gas screens.

Linearization is the function of making sure that the readings in between the zero and span point also read correctly. See the section below for this.

1.8.1 B

ASIC INSTRUCTIONS

1.8.1.1 S

Get into the

Select

Change any zero or span gas concentrations as desired. (Span gas values must be within 20 - 120% of the range fullscale.)

1.8.1.2 P

Get into the

Flow the appropriate span gas through the analyzer.

Select

ET SPAN GAS CONCENTRATIONS

Main menu

Expert controls and setup

Analyzer module setup.

Calibration gas list..

ERFORM

Main menu

Basic controls...

A S

PAN

Verify sample gas flow.

Press "SPAN", then "SPAN" again.

Press the left arrow or "HOME" when you are done.

1.8.2 A

As per basic controls, except do the span through the menu.

Enter the

Flow the appropriate span gas through the analyzer.

DVANCED INSTRUCTIONS

Main menu

Expert controls and setup

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

NTRODUCTION

Select

Verify sample gas flow.

Press "SPAN", then "SPAN" again.

Press the left arrow key, then press

Examine this screen for data about the most recent calibration.

Press the left arrow or "HOME" when you are done.

1.8.3 D

Spanning is less critical than zeroing. The analyzer will take several time constants to get to a good span value, so verify its signal is really stable before spanning.

Most span problems are due to the use of an incorrect span gas, or an incorrect span gas setting.

Expert controls and setup

Expert controls...

Results...

ETAILS

Network variables: CALTIME, CALTMEOUT, ZERO, SPAN, AMFN, CALCHKLIMITS, ZERORNGS, CALRANGES, CALFAIL, CALFPC

1.8.4 T

ROUBLESHOOTING

After a span, zero reads OK but the span gas doesn't read right…

You may not have left the span gas in long enough to get a stable span. Put the span gas back into the analyzer, and watch the trend of its reading on a chart recorder or computer screen. The reading should be stable when you do a span. If it is still trending upwards, you have not spanned on the real span gas. Either leave it to stabilize more, or troubleshoot your sample system until you get a good span gas stability. For example, entrained condensate in the system will affect the span stability. So will the presence of interfering compounds, such as ammonia added to control NOx emissions. You must remove these somehow.

After a span, the reading is very erratic…

You have spanned with a gas of much lower concentration than you think, typically zero gas or the measuring sample. Troubleshoot the sample system until you are sure that you are spanning off the real span gas, and also enter into the analyzer menu the real span gas concentrations. Enable limit checking so that this does not happen again.

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The analyzer refuses to span…

If the analyzer considers that it has to change its span factor by more than the allowed amount, it will refuse to span, if the calibration limit checking is enabled. Verify that you have the correct span gas, and its concentration is correctly entered into the analyzer. If so, troubleshoot why the analyzer's span has changed so much.

Possible cause are:

Contaminated sample cells in the NDIR and CLD analyzers

•

Loss of ozone production in the CLD

•

Flame out in the FID

•

Incorrect flame position in the FID

•

Incorrect pressures and flows in all analyzers

•

Rapid temperature changes (greater than 10°C per hour change)

•

Temperatures outside specification

•

Foreign substance contamination such as water carry-over

•

Large ambient pressure changes

•

Sample leaks either within or outside the analyzer

•

Exhaust back pressure changes

•

Incorrect linearizer coefficients

•

Span gas outside allowable range

•

1.9 LINEARIZATION

Analyzers often have a non-linear response to concentration changes in the sample, due to the

physical principles on which they work. In particular, NDIR analyzers operate more-orless on Beer's law, which states a logarithmic relationship between optical absorption and concentration. It is more or less logarithmic because practical gases are not ideal, particularly C02 at higher concentrations. The normal form of linearization used by NGA analyzers is the fourth order polynomial approximation. This is used for traditional and regulatory reasons. The theoretical solution would be to use a logarithmic approximation, however in computer terms this is merely a higher order polynomial, no different from the fourth order in precision in most circumstances.

Although in V2.2 analyzers there are a series of menus for automatic self-linearization, these are not operational in this edition of software. Instead it is necessary to enter or download the polynomial coefficients. These are determined by an external calculation, flowing known gases through the analyzer and recording its un-linearized readings, and calculating the appropriate corrections.

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NTRODUCTION

Frequent problems in doing this include errors in the dilution system used to generate the points, errors in the time allowed for the analyzer to stabilize after entering a gas, and errors in the calculation that determines the coefficients.

The NGA allows you to use up to four sets of linearization coefficients, and to assign these to any of the ranges, subject to certain limitations. Each set of coefficients has a range over which it is valid, and this has to be at least as great as 90% of the range to which it is supposed to apply. For each range you can select which set of coefficients to use, and whether to use any such set at all. If you select a set of coefficients that are not allowable, the analyzer will automatically select the next higher set, or the highest set if those sets are themselves valid for this range.

1.9.1 B

ASIC INSTRUCTIONS

In the

Select

Select which set of coefficients to use for each range.

Select

Press "NEXT" if necessary until you are dealing with the desired range.

Edit the

Edit the linearization fullscale range as appropriate.

Main menu

Expert setup and controls...

Analyzer module setup.

Gas measurement parameters...

Linearization parameters…

Linearization coefficients...

linearization coefficients

as desired.

1.9.2 A

748384-B Rosemount Analytical August 1998

DVANCED INSTRUCTIONS

Use a dilution system of known quality, proven with an known linear analyzer such as a FID.

Perform a zero and a span on the range desired. Verify that you have allowed plenty of time for the analyzer to stabilize.

Verify that the fullscale range setting is correct, and also the linearizer range settings are correct.

Flow a number of dilution samples for long enough to get stable readings, until you have enough data to generate the curve. This is normally between ten and sixteen

NGA Reference Manual

INTRODUCTION

points. Verify that you have given the analyzer time enough to stabilize - you are looking for an accuracy of reading of better than 0.1 % in order to generate a satisfactory curve 1 You may find it helpful to set the response time to a long value so that you have a good reading, or if you are using a computer for the data acquisition, make it do a statistical analysis on the signal to verify that you have no indication of a slope by the time you take the value.

Normalize the readings such that fullscale becomes equal to unity (divide the readings by the fullscale value). If your highest value gas is less than 100% of the fullscale, you must either change the fall scale value to that of the span gas or get a gas of the fullscale value. Trying to extrapolate to fullscale is not normally practical, and results in significant errors.

Using a least squares fit, calculate the polynomial coefficients. You may want to weight the errors so as to make the fit more accurate at the lower readings by making the error weight inversely proportional to that point's percent of range.

1.9.3 D

ETAILS

The polynomial coefficients are stored in a series of array variables called LINAO_[l..4], LINA1_[I..4], LINA2_[1..4], LINA3_[1..4], LINIA4_ [1..4]. These are the four zeroth coefficients (element 1 corresponding to the zeroth coefficient for range 1, and so on). They may be found on the linearization coefficient screens, where they can be edited, but it is usually more convenient to use a PC to download them into the analyzer.

Since the analyzer normalizes its signal, such that 0 corresponds to the range low end and 1 corresponds to the range high end, the linearization curve is constrained to go through the points 0,0 and 1,1, meaning that the sum of the coefficients should be 1.0. In fact, because of the allowable errors, the sum must be between 0.98 and 1.02 if a 2% error is allowed.

The curve must be monotonic. If it isn't, the zero or span algorithm may fail, resulting in an offset to the zero or span point. This is equivalent to saying that the first differential of the polynomial has to be positive over the entire –0.05 to 1.1 range.

The linearization should be performed at a specific temperature, and this has to be the same as the base temperature for the temperature compensation algorithm. Normally, 25°C is chosen for this, and minor errors will have little effect.

If it is desired to achieve accuracies of 2% of point, and 1 % of range, whichever is less (above 10% of range), fig s which are quite practical in most cases, great care must be taken to verify that the dilution system employed, and the settling time allowed, are adequate. Errors of 0.1% of fullscale at the zero end will make it impossible to achieve this kind of result. You may have to wait several minutes for the zero reading to "get there", once you have put in a span gas.

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It is essential that the gases used cover the entirety of the range. Don't try to extrapolate from an 80% gas to the 100% point, an error in your extrapolation will throw off the entire curve.

Network variables: LINA0_, LINA1_, LINA2_, LINA3_, LINA4_, LINSTAT, LINFORRANGE, LINRNGHI, LIN_OVER, LIN_UNDER

1.9.4 T

ROUBLESHOOTING

I use the self linearization screens, but nothing happens…

Version 2.2 software does not support self-linearization. You have to enter gases, take readings and figure out the coefficients externally.

I did a linearization, but my results don't check out with reference bottles…

Verify that you used a 100% gas, that the linearization ran-e matches or exceeds the fullscale range, that you have enabled the linearization at all and that you are using the correct set of coefficients (all of these are in the linearization setup screens under Expert controls). Verify that you have entered the coefficients correctly, and that their sum is close to 1.0.

If all of the above is OK, there is probably an error in your gas readings. Verify that the analyzer is correctly zeroed and spanned on the range you are using, and that you are using a long enough stabilization time. You may have to increase the analyzer's t90 time to get better signal to noise ratio.

Finally, you may have a problem with your dilution system, or your reference bottles. No matter how badly messed up the analyzer may be by this time, it should still read the same on the same gas. Make your blender produce the same concentration gas as a reference bottle, disable any linearizer, and read the two samples with the analyzer. If they don't read the same, something is wrong with either the dilution system or with the reference, and you will have to resolve this before you can resolve the linearity questions.

A common source of problems is the sample system in a CEMS installation. If you are losing concentration on the way down from the stack, due to leaks or water absorption or something, you may be unable to pass a linearity check when you introduce the reference gases at the probe. You will have to debug this. You may have lost concentration in a water trap, or you may have leaks. If the source adds ammonia to control NOx output, you may be condensing this in the sample cooler, and this will strip all NOx out of the sample.

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Linearization: Well I tried all that, but I have to make it work anyway…

If all else fails, and you have to make the analyzer work for political reasons without being able to resolve the real problem, you can use the tweak function described below. Remember that you are probably masking a real problem by doing so. Verify that the analyzer is really working correctly before resorting to this.

Some esoteric analyzer problems that can make it difficult to linearize include: FID use of N2 as the fuel diluent, and stratification at low hydrocarbon levels.

Saturation of the signal due to incorrect carbon content setting, sample pressure setting, or calibration gas value.

CLD - Inadequate ozone production, either caused by excessive sample flow, inadequate ozonator air flow, failure to use oxygen for higher than 1000 ppm concentration readings on a low range, or 2500 ppm on a high range unit, or a bad or tired ozonator lamp. Saturation of the signal caused by incorrect capillary setting or installation, and incorrect calibration gas values.

NDIR - Use of the incorrect cell spacer for the range you are working on, or incorrect settings of the temperature compensation factors.

All analyzers - Saturation of the analog signal path due to incorrect settings of gain resistors, or sample conditions, or specific parameters.

1.10 LINEARIZATION TOUCH-UP

NGA analyzers have two forms of linearization available. One method is to "tweak" them. This involves selecting up to three mid range values, and forcing the reading to correspond to the gas values at these points. The analyzer will then interpolate intermediate readings appropriately. This feature is useful when attempting to correlate the analyzer's performance against some standard gases of dubious accuracy, but where the gases must be believed. It can also be used to adjust the normal linearity adjustment for the particular idiosyncrasies of a gas divider, which itself may have linearity problems. In this case, perform the normal fourth order polynomial linearization, and then "tweak" the curve in using this tweak function. A preferable solution, incidentally, is to correct the gas divider or calibration gases.

1.10.1 B

Select the operating range desired.

ASIC INSTRUCTIONS

Zero and span the analyzer in the normal way.

Select

Expert controls and setup

Analyzer module setup.

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Select

You arrive at the setup for range 1, cycle through the other ranges by pressing

Set

Setpoint being measured:

Flow the appropriate value of gas (typically 30% of scale).

Edit

When the reading has stabilized, press “SET”.

Setpoint being measured

Flow the appropriate value of gas (typically 50% of scale).

Gas measurement parameters...

Linearization functions...

Midpoint correction setup...

"RANGE 2", "RANGE 3" and “RANGE 4" as desired.

Correction:

Point 1 gas concentration

to enabled.

to point 1.

: to the named value on the bottle.

: to point 2.

When the reading has stabilized, press "SET” .

Setpoint being measured

Flow the appropriate value of gas (typically 75% of scale).

When the reading has stabilized, press "SET” .

Now do the same procedure for any other ranges you want to tweak.

1.10.2 D

This algorithm applies a segmented straight-line approximation to the signal after the polynomial linearization has been done. It forces the reading through the points measured, and interpolates between the points on a straight line basis. You should only use this with care, to have to use it essentially admits that there is something wrong with the normal linearization setup, either a fault in the analyzer somehow or a fault in the test gas setup. The most usual reason for using this is to “correct" (actually, un-correct the analyzer) for inaccurate mid-point check gases in an EPA CEMS system. However if you are trying to linearize an analyzer to 2% of point at 2% of scale, this feature may save you when all else has failed.

ETAILS

: to point 3.

Network variables: MID_GASA, MID_GASB, MIDPOINTA, MIDPOINTB, SPAN_THEN, TWEAK

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1.10.3 T

The normal reason for failure with this procedure is an error in the setup. Verify you are editing the point that you have selected, or that you have selected the point you are editing. If you have messed up, go back and redo the points. Verify that the zero and span calibrations are correct. Also verify that you have selected the correct linearization curve, and that it is enabled. Verify that the analyzer is working correctly, for example that the ozonator lamp in a CLD.

ROUBLESHOOTING

1.11 RESPONSE TIME

The analyzer has a natural response time based on its gas passage design, and the response time of its sensor. However it is possible to add additional filtering to the signal, which will have the effect of increasing the response time while reducing the noise level.

The natural response time may be modified by changing the flow rate through the analyzer. This affects both the rise time and the delay time - the rise time is the time it takes from the beginning change in the output to the time that 90% of the final change has occurred, while the delay time is the time from the introduction of gas to the back of the analyzer to when that initial reading change occurs. The delay time will be reduced by increasing the flow rate, and the rise time may also be reduced in the same way, but only for flow sensitive analyzers such as the NDIR types. Note that increasing the flow may also change the response level, due to pressurization of the sample cell. The term “response time" is loose - sometimes it can refer to the rise time and sometimes to the overall response, rise time plus delay time. In the NGA it is used to refer to the rise time only.

In general, increasing the amount of filtering by editing the response time setting will first increase the order of the "Median" filter (this will also slightly increase the delay time), and then to increase the time constant of the third order infinite-impulse-response (IIR) software filter. The IIR filter is disabled for response times below about 0.5 seconds. Setting the response time to zero will completely disable all filtering.

You should normally set the response time for the longest possible value for your application.

The delay time should be set so as to delay the fastest responding analyzer in the system so that it responds at the same time as the slowest. The delay you need to be concerned with is the time from a sample gas change at the entry port to the time the reading just begins to move, not until it reaches its full change. You are then compensating for differences in sample path, as well as differences in analyzer performance.

The delay time adjustment was disabled in V2.2 of the PMD and NDIR analyzers, but enabled for V2.2.1 and later. Also on this screen is the LON update rate control. This

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NTRODUCTION

sets the speed at which this particular analyzer updates its PVA variable -the primary or process variable, the main reading - over the LON. In almost all cases, setting this to 10 per second will be satisfactory. You can set it to ASAP, in which case it will update the PVA at up to 33 Hz, but doing so may make the system less responsive, particularly if you have several analyzers all on the LON together. The symptoms of excessive network traffic include difficulty getting PCs to update variables, and occasional lost menus - the system will seem to lock up, and only the left arrow key will work, then it will apparently come back to life again. They also include random failures generally in the network, such as I/O modules that do not respond to their analyzers. If this latter occurs, set the LON update time as above and then if the symptom does not go away immediately, rebind the I/O modules.

Network variables: AFT90_, AMDELAYTIME, LONPVUPDATE

1.11.1 B

Set the analyzer flow rates as desired.

Enter the

Select

Edit the response time for each range as desired.

Edit the delay time as desired for the fastest analyzers in the system.

Edit the LON update rate for the desired rate, normally 10 per second.

1.11.2 A

The menu paths as above.

ASIC INSTRUCTIONS

Main menu

Expert setup and controls...

Analyzer module setup.

Gas measurement parameters...

delay/response time parameters...

DVANCED INSTRUCTIONS

Set the response time values for longer times on the lower ranges.

If there are apparent network collision problems, set the LON update rate to 1 per second.

For the most precise calibrations, set the response times to 20 or 30 seconds prior to a calibration, and then set them back to short times for operation.

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1.11.3 T

ROUBLESHOOTING

Noisy analyzer signal…

The response time may be too short. Increase it until the noise level is satisfactory.

Poor system response to menu changes, and poor response to variable editing…

The LON update rate is too fast in one or more analyzers. Go through them all, setting the update rate to 10 per second from ASAP, or 1 per second. Via a PC, the variable to change is LONPVUPDATE, and it should be set to a value of 1 or 2.

One analyzer in a system responds faster than another on the same gas change…

Set the response time of the faster analyzer to the same as that of the slowest one. If there is still a problem, set the delay time of the faster analyzer so as to delay its signal compared with the slowest one. It can be hard to do this properly if you have very different response, times.

1.12 ANALYZER MODULE HISTORICAL DATA

Analyzer Modules contain varying amounts of historical data - values of parameters stored when the module was manufactured (or otherwise stored). These may be found in the diagnostic menus, normally either on a separate history menu or else shown alternately with the current data on the same menu.

The intention is to show how the analyzer was configured when it was tested, and therefore allow you to spot any differences that may be contributing to some performance shortfall.

It is possible to use this feature to store the current data in this way, if it is desirable to do so. Generally you should not do this unless you are sure that the analyzer is performing correctly, as you will overwrite the previous data and you will not be able to restore it.

It is also possible to store known good zero and span factors. In the screens showing the zero and span factors there are links to screens showing historical factors, and softkeys that store these, and also restore them into the current factors.

Network variables: AMVOLTSWAS, CONV_TEMPWAS, HIST2T_, HIST2V_, SPANWAS, ZEROWAS, WNXVOLTSWAS, SPAN_GOOD, ZERO_GOOD, CURR_WAS, PWAS, FLOW_WAS, TEMP_WAS

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1.12.1 B

Enter the

Enter

ASIC INSTRUCTIONS

Main menu…

Technical level configuration

Service menus...

Manufacturing data...

Analyzer module data.

...

Press "STORE", and after reading the caution screen, "STORE" again.

Press the "HOME" key to get back to the

t90

Time

1.0

A/D

reading

from Signal Board

2.0

Digital

Filter

3.0

Zero/Span

Adjust

is value

between -0.05

and 1.05

Main menu

YES

Calibration

Coefficients

4.0

Linearize

(4th order)

5.0

Temperature

Compensation

6.0

Multiply by CALRNGHI to generate

PVA

Calibration

Function

IGURE

1-2. A

NALYZER ALGORITHM

1.13 ANALYZER ALGORITHM

The Analog to digital converter is read 30 times a second. The value is stored as an integer in the 20 bit range.

There are 2 digital filters: A 7 point median filter followed by an IIR filter (controlled by the t90 time).

In the zero/span adjust section the raw signal (the output of the digital filters) is linearly converted to a scale based on the calibration coefficients (span factor and zero offset) using the following equation:

Output = SpanFactor * (Input -ZeroOffset)

If the output of the zero/span adjust is between -0.05 and 1.05 then the value is

PVA

Out

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linearized. A forth order linearizer is used with the following formula:

Output = C0 + C1*Input + C2*input2 + C3*lnput3 + C4*lnput

The output of the linearizer (if used) or the zero/span adjust is input to the temperature compensation. The temperature compensation algorithms is as follows:

TempCompMultiplier = 1 + CaseTemperature + TempCompFactor

Output = input + TempCompMultiPlier

This feature is not normally used in the FID.

The output of the temperature compensation function is multiplied by CALRNGFU to generate the PVA output. The calibration routine (which is actually two routines a zero routine and a span routine) is used to adjust the span and zero offsets used by the zero/span adjust routine. It tries to adjust the factors so that when a 0 ppm gas is read a 0 will be output from the temperature compensation section and when a RNGHI ppm. gas is read, 1 will be output from the temperature compensation section. This is achieved using a successive approximation technique.

The values of the raw signal from the 20-bit ADC are typically 520,000 at zero, and somewhere under 900,000 at the highest fullscale range. The span value is quite variable and it depends on a series of factors as shown below.

Range fullscale values. In the case of the FID analyzer only, it sets its PGA gains and its preamplifier gains used based on a rather complicated algorithm. It does this in such a way as to verify that the maximum signal seen is less than the fullscale counts for a fullscale gas. The factors considered are: the range fullscale value; the response factor (methane or propane, etc.); the fuel type; the sample gas pressure; and the type of capillary. These gains are set for each range, but are not changed dynamically. Earlier than V2.3 CLDs adjusted their PGA gain based on the fullscale value, dividing the gain by 2 for every doubling of range above 100 ppm. Later CLDs and other analyzers do not use a PGA.

In the case of the FID, the pre-amplifier acts as a current-to-voltage converter, and its transfer ratio is selected from two alternatives by choosing either a 200 M or a 5 G feedback resistor. Following this there is a PGA which can select its gain from values of 1, 1/2, or 1/4. For methane and mixed fuel, the preamp changes gain at a fullscale range of 850 ppm. For methane and pure hydrogen, the equivalent value is 270 ppm. These values vary according to the other factors mentioned. It is not in general possible to say what scales are used in what ranges, but that information could be determined from a table.

You can display the main reading at a resolution of up to seven significant figures (on

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

the platform). The PVA value is transmitted to a PC as a floating point value, also of about seven significant figures of resolution. The PC can display it according to its programming. This means that you could display the reading to hundredths of a ppm if the value of the reading is less than 99999.99 ppm. However, the noise level of around 0.1% of reading typically will make this of questionable value.

Network variables: RAW_SIGNAL, ZERO, SPAN, LINSTAT, LINA0_, LINA1_, LINA2_, LINA3_, LINA4_, CALRNGHI, BAROMETER, CAL_PRESS, CAL_PRESSURE, PVA, PVACEMS

1.14 SECURITY

You can enable security for each or all of the three main branches of the menus. In each case, you have to enter a five letter password in order to enter the appropriate section of the menus. Once you have entered the password, you will be able to enter or leave that section of the menus at will, unless you leave the instrument unused for a time out period, in which case you will have to re-enter security. If you make the passwords the same for each branch, entering one branch will disable security for all branches.

NTRODUCTION

You can also set a time out for the menus themselves, after which the display will jump out of the menus. This in effect is another security device - it is practically impossible to figure out what to do in time if you set the time out to 10 seconds, thus it keeps people from making unauthorized adjustments.

Pressing the "LOCK" button on the main display screen will enable security immediately, cutting short the normal hold-open time.

1.14.1 B

Enter the

Select

Enable whichever set of codes you wish to use.

Select whichever security code you wish to configure.

ASIC INSTRUCTIONS

Main menu…

Technical level configuration

System setup

Security codes...

...

Press the buttons in a suitable order. The code will be shown as a number.

Press the left arrow key when you are done.

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Setup the other security codes as desired.

Press the left arrow key until you are in the

Select

Set the

1.14.2 T

Front panel control...

Drop out of menus after:

This line controls how long it will leave the menus showing after you have pressed a key in one.

ROUBLESHOOTING

System setup

line to a suitable time.

menu.

Someone put in a password and now I'm locked out…

Call Rosemount Analytical Service and they will tell you a secret back door password. This will allow you to enter the you can reset all the other passwords.

Technical level configuration

security screen, and then

I put in passwords but I still don't have any security screens…

You have to enable security for each level you want it to work on. Do this in the screen immediately above the security password entry screens.

1.15 DATE AND TIME

The control module contains a real time clock which keeps accurate time despite power interruptions. It is normally more accurate than the clock in a PC. Every so often it updates the software clock in the other modules. A software clock is less accurate, and it loses its mind if the power fails. Such clocks are kept in the analyzer module computers, and also in the Autocalibration I/O modules.

Set the clock in the menus.

See the Autocal module instruction manuals for details about setting up their timing.

Network variables: I_TIME, C_ TIME

1.15.1 B

Enter the

Select

ASIC INSTRUCTIONS

Main menu

Technical level configuration

System setup

...

menus under the

...

Technical level configuration

...

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Select

Edit the time display format, and the hours, minutes, month day and year.

When all is satisfactory, press the "SET” button.

The

Verify that the

Date and time ...

Current time:

network updating:

line should now show the correct date and time.

line is enabled.

1.16 SCREEN APPEARANCE

The appearance of the single analyzer display screen can be altered. You can select how many figures are displayed by the main reading, and you can select not only what the four auxiliary lines display, but also from which module they come, analyzer, I/O or Autocal.

1.16.1 B

Enter the

Select

ASIC INSTRUCTIONS

Main menu

Expert controls and setup

Select

Choose the number of digits to be displayed altogether, and the number if any to be displayed after the decimal point.

Press the left arrow key.

Select

Enable the number of auxiliary lines you want to show.

Select the source of each auxiliary line, following the menu instructions.

Press the left arrow key until you get back to the

Select

System setup

Main display configuration...

Display resolution...

Auxiliary lines...

Analyzer module setup.

Displayed physical parameters...

...

Expert controls and setup

screen.

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Select the parameter to be displayed on each line. (This parameter will only be displayed if both this module is selected as the source for this line, and the line is enabled as above.)

Press the left arrow key twice, and select

Select the module you want, and then select

Select the parameters to be displayed from this module.

Auxiliary module setup...

Displayed parameters...

1.17 MANUFACTURING AND SERVICE DATA

The individual modules contain a menu that shows the manufacturing data appropriate to the module. It shows the serial number, the software revision, and other such data that is of use in quality assurance programs.

It can be found under

Also in this area are the service history menus. You can use these to record in service and last service dates, and you can also record service notes here if you want. The info screen for the control module shows the standard Rosemount Analytical service codes. Use these to save time editing letters.

You can also record security codes from this area. The menus are identical to those in

System setup

Technical configuration...

, under

Service menus...

Network variables: AMSERNOTEA, AMSERNOTEB, AMSERNOTEC, AMSERNOTED, AMSERNOTEE, AMSERNOTEF, AMSERNOTEG, AMSERNOTEI, AMSERNOTEJ

1.18 ANALYZER STATUS

There are several kinds of status information reported by the analyzers. These include its alarm status, its operational status and its sampling status, its calibration activity and the validity of its output reading .

These are all reported over the network in the form of variables, and they are shown in various places in the menu structure.

1.18.1 H

The analyzer continuously monitors the state of a whole series of internal parameters. It also monitors its operational parameters such as pressures and flows. The operational parameters may be assigned upper and lower limits, while the internal parameters have such limits fixed by the programming.

EALTH (ALARM STATUS

)

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If a limit is exceeded, an alarm flag is set, and the alarm status variable is set to a level corresponding to the severity of the parameter. Most parameters cause a WARNING state to be set, but the internal parameters may cause a FAILURE state to be set. If any of the parameters is outside its Emits, this state will be set.

If you have allowed it to (by enabling alarm reporting in the technical setup section), a message will be displayed on the screen as well.

Otherwise you can show the alarm state by selecting "Health" to be reported in the auxiliary line selection under

You can set an I/O module to report this by setting up its alarm parameters to report the analyzer alarm state in the

Network variables: GENERALSTATE

Expert controls and setup

Auxiliary module setup

under

Expert controls and setup

1.18.2 A

The analyzer may be in normal mode, in standby (meaning that it has not warmed up yet, or otherwise cannot take readings), or is in calibration. This state may also be reported in the auxiliary lines, and by the I/O module.

Network variables: OPSTATUS

1.18.3 A

An I/O module that controls the sample flow, such as an Autocal module or a sample stream selection module can tell the analyzer that it is not looking at the sample. This can also be reported like the other variables.

Network variables: PROCESS

1.18.4 A

The analyzer reports when it is in the process of performing a zero or span. This is shown on the zero and span screens to tell you what it is currently doing. This information is also reported to an Autocal module as feedback so that the latter can tell when to go onto the next step.

NALYZER OPERATIONAL STATUS

NALYZER SAMPLING STATUS

NALYZER CALIBRATION ACTIVITY

Network variables: CALSTAT

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1.18.5 A

The analyzer reports the status of its last calibration, together with its time and other data. This may be found on the "Results" menu under

controls and setup

Network variables: CAL_ERR_MSG, CAL_RAWSIG, CAL_VALIDITY, CALDATE_Z, CALDATE_S

1.18.6 A

The analyzer attempts to determine whether its readings may be regarded as valid or not. It looks at the operational state, and the health state (both must be normal), the sample flow (which must be above a minimum value), the sample and other pressures, its calibration state and whether it is being fed the sample or a not-from-process gas. It may also look another specific analyzer factors. If any of these are out of specification or clearly inappropriate, it reports its VALIDITY variable as INVALID. This may be seen on the auxiliary lines, and reported via the I/O module like the other status variables.

NALYZER CALIBRATION STATUS

NALYZER VALIDITY STATUS

Expert controls

, under

Expert

Network variables: VALIDITY

1.19 ANALYZER INTERNAL DATA STORAGE

Analyzers store up to 24 hours of averaged data in their volatile memory. It is stored as 96 fifteen-minute averages. You can select which two variables out of a list of about 20 are stored. The analyzer validity, and calibration status, as well as the time of each segment are stored.

This data can be retrieved using a computer interface. It is not available through the menus.

It is intended for certain CEMS monitoring requirements where data must be reported to a monitoring authority, and absence of data due to, for example a fault in the monitoring computer will cause significant monetary cost.

Note

The data is volatile!

If you lose power, the data is lost. However if the analyzer power stays on, the data remains despite network upsets and anything else that happens.

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1.19.1 B

Select

Select the desired parameters to store.

Setup a computer with a suitable LON interface.

Using the DDE server program and an application such as Excel, use a macro or

It will take a few minutes to download all the data.

1.19.2 D

The data is stored in an array inside the analyzer memory. The data may be retrieved by the use of two specific variables, DATA_INDEX and DATA_POINT.

ASIC INSTRUCTIONS

Technical level configuration

Diagnostics menus...

Analyzer module diagnostics...

Trend display control...

program to interrogate the analyzer.

ETAILS

...

You set DATA_INDEX to refer to a particular data point, wait for about one second, and then read DATA_POINT.

Both these variables are arrays, whose elements refer to specific things. See the variables appendix for details.

The Excel example spreadsheet called NGATREND.XLS shows how to do this in the Visual Basic for Applications language.

If the analyzer has not been powered for the full 24 hours, the unused sets of data will be filled with large negative numbers. This is so that it will be obvious that the data is not correct.

The analyzer puts the data into the appropriate time slot. If its internal clock is not corrected by a platform, this may be wrong. However the analyzer will store the time for each data point along with the data, so you can see which data is which. The data is retrieved point by point, so that you have to be aware when the day has rolled over.

Network variables: DATA_POINT, DATA_INDEX

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1.19.3 T

ROUBLESHOOTING

I only get one data point…

You probably are not writing the DATA_INDEX correctly. Verify that this variable is indeed being written. Excel does not tell you if it has failed to poke a value. Common reasons for this include having the wrong network address, trying to poke a variable or a value, rather than a spreadsheet cell address, or a typo in the variable name.

You may also not be waiting long enough for the analyzer to respond. In the Excel example above, the macro writes DATA_INDEX, then reads DATA_POINT and does so repetitively until the index reported in this variable is the same as that requested.

I get lots of data, but it has a discontinuity in it…

The time rolls over after 24 hours. Each point is stored at a particular segment of memory, overwriting the point stored 24 hours earlier. So if you read the points from 1 to 96, somewhere the day will switch from today to 24 hours ago.

Use the reported time cell to sort the data so it is an appropriate order.

The data seems to be full of garbage…

The analyzer stores internal data in volatile memory. If there is loss of power, this memory is reset. When this happens, the internal storage is set to nonsense values, and the analyzer starts recording data in the area in the memory appropriate to the time of day, if it knows what that is from a network update. Only the section of memory that has been filled since the power failure will have any meaningful data in it.

1.20 SERIAL I/O MODULE

There is available in the platform a non-LON I/O module that can produce up to 8 channels of 12-bit analog outputs, as well as 3 alarm contacts and a serial (either RS232 or RS485) port.

1.20.1 D

The serial I/O board is not a LON module like the other I/O modules. It communicates directly to the processor in the control module. As a result its menus are not like those in the single channel I/O modules.

Its analog outputs are arranged in groups of two. Each output is available as both a current and a voltage simultaneously, although you can only calibrate one of these at a time. Each output is isolated from the main analyzer and control module ground, but each pair has no isolation between themselves, they share a common ground with each other.

ETAILS

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NTRODUCTION

You can add up to three more pairs of analog output onto an serial I/O board. However you can only have one serial I/O board in a system.

You can add a serial interface module to the serial I/O board, configured either for RS232 or RS485. You can then select which interface protocol to use with this. See the interface section of this manual below for details.

You have to configure the serial I/O card manually, telling it what modules have been installed. Telling the computer the wrong thing will degrade the response time of the system, but will not cause a crash.

1.20.2 T

ROUBLESHOOTING

I configured the serial I/O module output but nothing happens…

Verify that you do in fact have an serial I/O card installed, remember that the menus are there regardless. Also verify that you have connected wires to the correct I/O board, not to a normal I/O card.

Also, verify you have edited

Module installed

: to YES.

I set the serial I/O module up for ModBus (or AK) and nothing happens…

Verify that you have the serial interface option installed. You have to do this by looking at the board.

Also. verify that you have selected the correct module type under

serial interface:

Type of installed

How do I configure the relay outputs of the serial I/O module…

The relays are not configurable. They only work as described above.

If you want to have concentration alarms you need to use an analog I/O module.

1.21 NETWORK ISSUES

NGA analyzers operate over a digital network called the LON. All of the internal data is available over this network.

It is possible to access this information directly using appropriate hardware and software, but to do so requires a certain amount of software effort. To avoid this, and to accommodate users with investment in other protocols, several methods of retrieving this information and allowing control and configuration of the analyzers directly have been included.

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INTRODUCTION

1.21.1 LON D

Data is sent over the LON as discrete packets called "Variables". These correspond with normal programming variables, except that they are available to anything on the LON capable of reading them.

There are also other packets of information used by the NGA system, but these are not accessible to non-NGA devices.

LON variables may be of four basic types, floating point, integer, enumerated or string. In addition, all but string variables may be packaged into arrays, with a maximum of seven floating point numbers per array, or ten integer or enumerated types per array.

NTEGER

A number between 0 and 65535, expressed as a 16-bit number. There can be up to 10 integer variables in an array.

LOATING POINT

A four byte IEEE floating point number (in Motorola format). This is a number that can take a very wide range of values, but provides only about seven digits of precision. The analyzer main reading is expressed as a floating point number. There can be up to 7 floating point variables in an array.

ATA

NUMERATED

An integer number whose value corresponds to a phrase. These are used to express one of several possibilities. A typical example is the variable that determines whether or not a linearizer is enabled: a value in the variable of 0 is translated as DISABLED, while a value of 1 is translated as ENABLED. There can be up to 10 enumerated variables packaged in an array.

TRING

A string variable contains up to 31 characters of ASCII. These are numbers which refer to the standard letters, numbers and odd symbols in the ASCII character set. There are in general no restrictions on the symbols contained in a string variable, except that the DDE server may not work correctly if analyzer TAG variables contain symbols other than the alphanumeric set. There are no string arrays.

1.21.2 LON D

See Section 2 for details.

ATA DETAILS

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

1.22 MODBUS

ModBus is a protocol developed by Gould Modicon, who provide documentation for it. The protocol is in the public domain. It operates over RS232 or RS485 links. It is a master - slave protocol - a master requests or writes information, and the slave responds. In the NGA case, the NGA control module is a slave.

In ModBus, all information is defined as existing in "registers", accessible by their address. These registers may contain integer, floating point (in our implementation) or string information. Registers are addressed by a scheme that determines first the analyzer module (or subnode) with which it is desired to communicate, then the variable address within the analyzer. All NGA variables are available as registers. These may be read or written to, though output variable registers will ignore anything written into them.

The host may access individual registers, or may define a list of variables that can be addressed as one. This definition may be performed either as a ModBus command or via the control module.

NTRODUCTION

A list of available variables and their corresponding registers is available from the ModBus connection directly as an ASCII file.

1.23 PC LON INTERFACE

It is possible to connect a PC to the LON. You can monitor variables, and you can write values into the configuration variables as desired.

It is possible to write software that uses Echelon libraries to directly interface with the LON, however this is not an undertaking for the faint of heart. If the performance limitations are acceptable, a better alternative is to use the DDE function in Windows to enable high level applications such as Excel or Labview to communicate with the analyzers.

Rosemount Analytical can supply a package of software that allows this functionality. This consists of a "DDE server" program, and some examples that show how to use it.

1.23.1 P

Windows allows a cycle time of about 65 micro seconds for the DDE protocol. This means that it is possible to get about 10 variable updates per second through the DDE server.

ERFORMANCE

The DDE server is restricted to polling the network - that is to say it has to request a data update every time it wants one, rather than simply listening to the network the way the control module does. This also Emits the performance and may interfere with the operation of the control module menus (they will get slower and unresponsive eventually).

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All Windows programs tend to be somewhat unstable, particularly if there are many entries and exits of Microsoft applications, due to the memory "leakage" problems afflicting them. It is as well to have someone check a PC for correct operation on a daily basis.

At this writing, Windows95 operation has not been tested.

Note

It is not possible to write data into a platform control module from a PC, due to the control module's acting as a network manager.

It is also not possible to write configuration data into an I/O module, since its configuration variables are configured as output variables.

1.23.2 B

A suitable LON hardware interface must be installed and its driver installed into the "CONFIG.SYS" file. For example, using the Echelon SLTA serial device, the driver LDVSLTA.SYS must be installed into CONFIG.SYS, with appropriate switch settings (/p1 /d1 /a is typical). See the Echelon documentation for details. Reboot the computer so it takes effect. You may have to use the memory management utilities until the DOS memory is adequate for the applications.

Install the Rosemount Analytical DDE server program by typing "SETUP" in the Run... prompt of the Windows program manager. It will be installed together with the example files into a new directory called NGASUITE.

Start the DDE server program. It will interrogate the network, and once it is done it will retire to an icon. You can open the icon and select "File", and then the network information, and see what nodes are found. The names and addresses of the nodes can be directly edited by double clicking on the appropriate field.

Verify that the TAG names do not contain periods or arithmetical signs such as "-“ or “/”. Edit them if they do.

Further help can be found in the accompanying documentation and in the "Help" screens built into the DDE server itself.

ASIC OPERATION

Open the desired Windows application and use its DDE functionality to transfer data to and from the DDE server.

1.23.3 D

Variables are continuously updated by their source modules. If the module has been bound to another, they will be updated onto the network and sent to whichever nodes

ETAILS

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NTRODUCTION

it has been bound to, if only the control module.

Certain LON devices can listen in to this traffic, but the DDE servers provided either by Echelon or Rosemount Analytical are not capable of doing this, they have to specifically request data. They also need to have a variable data base so as to be able to understand the data. This has to be provided externally to the Echelon server by the Rosemount Analytical MAKE_API program; the Rosemount Analytical server makes its own database automatically.

If analyzers are used with no control module, it is helpful to disable their autonomous outputting of data. They have normally been checked out with a control module, and therefore think that it is still there, and so they try to communicate with it. You can disable this by running the MAKE_API program with the switch "-c", i.e. MAKE_API -c. This will improve the performance of such networks.

The Rosemount Analytical DDE server program provides a number of features that are optimized for the NGA system, and thus is the preferred solution. In particular it reports the population and identity of modules on the network, allowing applications to configure themselves automatically and removing the need for user to understand what is happening.

The following is a brief explanation of how to use the Rosemount Analytical DDE server program.

DDE is a Windows feature that allows programs to communicate with each other. It is organized as a "conversation", with topics and data. You start a conversation, determine a topic and request or write (Poke in Visual Basic, or Excel) data.

1.23.4 U

1.23.4.1 B

Excel can either read variables directly into the spreadsheet using a formula, or it can read them by requesting the data in a macro. It can only write into a variable using a macro.

Macros in Excel (v5.0 or later) are written in a kind of Visual Basic (called VBA, Visual Basic for Applications). The examples given here are written in that language. Please see the Microsoft documentation for definitions of the terms used in the following paragraphs.

When reading a variable, the result is returned as an array of characters. If this is written into a cell in a worksheet, it is automatically turned into a number or string or whatever is appropriate - except for dates, which are helpfully translated into the date serial number. You can translate it back by formatting the cell as a date.

SING EXCEL WITH THE

DDE P

ASIC

DDE S

OINTS IN EXCEL

ERVER

If you try to assign a DDE request into a VBA variable, unless you declare the variable

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INTRODUCTION

to be of type variant, or declare it to be an array of strings, it will give you an error. If you want the variable to be a number, or a string, you have to convert it in some way. The easiest way is to write it into a worksheet cell, and then read it back. Otherwise you can use a function to do it, an example of which is

"LON-into-string0" in the excel spreadsheet examples.

The only way to write (or poke) a variable is to write a spreadsheet cell. You cannot write a value of a cell, or a variable. If there 'is an error in defining the cell, the poke function will fail and it will not tell you why. The cell must be formatted as text, you cannot write a number or a date.

1.23.4.2 S

The TAG can be used as the node name, or the node number.

The TAG MUST NOT contain spaces.

Using the node number:

n is the node number. Note the " ' " before and after the address variable string.

PREADSHEET CELL FORMULA

=NGDDESRVInetvar!Node_name

VARIABLE_TAG

=NGDDESRVlnetvar!TAG

VARIABLE_TAG

=NGDDESRVInetvar!’”n"

VARIABLE_TAG

1.23.4.3 TO G

+NGDDESRVlnetvar!TAG

VARIABLE_TAG [n]

n is the array element

The DDE server does not check for out-of-bounds arrays.

1.23.4.4 R

Start a DDE conversation

ET AN ARRAY ELEMENT

EADING

A V

ARIABLE

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NTRODUCTION

Dim DDE_Channel as Integer

DDE_Channel = DDEInitiate(DDESRVR, netvar)

Setup to read a variable

Dim Variable-return as variant

Dim LON_Address, Analyzer_tag, Variable_name as string

Establish what ANALYZER_TAG and VARIABLE_NAME are here. The Chr(34) expression inserts a quote ("), used to handle the case where the TAG variable contains non-alphanumeric characters, such as #, &, +, or - . You can't write “’” in an attempt to persuade VBA to insert a quote, you have to use the Chr(34) function. 34 is the ASCII decimal code for a quote.

LON_Address = Chr(34) & Analyzer_tag & Chr(34) & "" & Variable_name

Variable_return = DDERequest(DDE_Channel, LON_Address)

Write it into a spreadsheet cell

Worksheets(Worksheet).Cells(Row_number, Column_number).value=Variable_return

Worksheet, Row - number and Column= number are variables or expressions that determine which spreadsheet, and which address you are using.

1.23.4.5 E

The DDE server provides a list of the analyzers and their types present on the LON. This can be obtained by opening a conversation with the topic "Nodelist". Asking for "number" will tell you the number of nodes found, and asking for “get" will return a list of them and their types.

In a macro, open a DDE conversation with the expression

Get the number of nodes present:

STABLISHING ANALYZERS PRESENT

Dim DDE_Channel as Integer

DDE_Channel = DDEInitiate(NGDDESRV, nodelist)

Dim Number_of_nodes as String

the return from the DDE server

Dim Integer_number_of_nodes as integer

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INTRODUCTION

the result we want.

Dim Variable_return as variant

(You don't need to do this twice if it has been defined before)

Variable_return = DDERequest(DDE_Channel, "number")

Number_of_nodes = LON_into_string(Variable_return)

LON_into_string is a function you can find in the demo spreadsheets. It converts the array returned by the DDE link into a string.

Integer_number_of_nodes = Right(Number_of_nodes, Len(Number_of_nodes) -1)

Number_of_nodes is a string "An", where n is the number of nodes. The above expression strips off the "A" from the front of this, and converts the "n" into an integer.

Now get the list of nodes

Dim Node_list_array as variant

Dim Node_list as string

Node_list_array = DDERequest(DDE_Channel, "get")

Node_list = LON_into_string(Node_list_array)

NODE_LIST will be a set of triplets, arranged as NODE_NUMBER, NODE_TYPE, and NODE_TAG. The series repeats for each node.

See the spreadsheet "NGCHECK.XLS" for an example of how to extract node names from this string.

1.23.4.6 W

The only way to write to a variable is to use a macro expression.

Using the variables defined above, supposing that you want to write the contents of the cell defined by ROW_NUMBER, COLUMN_NUMBER to the variable LON_VAR:

RITING TO

A V

ARIABLE

Use the following format.

LON_Address = Chr(34) & Node_tag & Chr(34) & "" & LON_VAR

DDEPoke DDE_Channel, LON_Address, Worksheets(Worksheet).cells(Row_number, Column_number)

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

This will write the contents of cell; Row_number, Column_number in worksheet whose name is stored in the variable Worksheet, into the LON variable LON_VAR.

Note

The worksheet cell MUST be formatted as text! Also note the absence of parentheses.

1.24 AK

AK is a European automotive protocol. It runs on RS232 or RS485. It is structured as a series of ASCII strings that require a particular response. Analyzers made in the USA do not in general support the entire AK command set, however they do support a new command pair that allows reading and writing of any NGA variable.

NTRODUCTION

1.24.1 AK E

First, configure the platform to accept AK. Verify it has an "serial I/O" board with RS232 adapter plugged in, and under

setup interface:

default values are normally correct.)

In the terminal emulation program under Windows, set the function keys to have

commands as follows:

Put in other commands as you desire. In general, the line is:

XAMPLE USING THE WINDOWS TERMINAL EMULATOR

Expert controls and setup

. In this screen, set the

to RS232. (You may have to set the configuration parameters, but the

Label "Reading" - command "^M^B_AKON K1^C”

Label "Flow" - command “^M^B_ASVC K1 S600 FLOW_IS1^C”

Label

^M^B_ASVC Kn S600 VAR_TAGm^C

"Pressure"

is the node number - "0" gets all the nodes

- command

Module installed

“^M^B_ASVC K1 S600 PRES_ IS1^C”

: to Yes, and

, select

Type of installed serial

Local //0

VAR_TAG

is the array index (I based) of an array variable.

S600 refers to the non-standard AK service function number 600 used for this.

For zero and span commands, use ^M^B_ ^M^B_ESVC Kn S600 AMFN 2^C to span, with reset to 0 after a second or so of each command(^M^B_ESVC Kn S600 AMFN 0^C).

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is the tag of the variable

ESVC Kn S600 AMFN 1

NGA Reference Manual

^C to zero, and

INTRODUCTION

1.25 ALARM I/O MODULE GENERAL INFORMATION

Information about this module may be found in the Platform manual. However there are some more subtle points not covered there.

Version V2.2 and earlier I/O modules had general alarm functions, but were not capable of responding to specific analyzer conditions or of giving analyzers specific commands. Version 2.3 and later I/O modules are capable of both of these functions. They are controlled by a modification of the menu handling code in the V2.3 Platform Control module that is capable of putting values from analyzer variables into the I/O module menus, thus allowing the user to select analyzer specific options.

Network variables: AM_INPUT, DI_MSGE, ST1NAME, ST2NAME, STCONT

1.25.1 S

1.25.1.1 B

See binding above.

1.25.1.2 S

The analog output is available either as a voltage or a current output. However only one is meaningful at a time, the other one will have incorrect readings even though it is physically present.

You can setup the output to track the analyzer ranges, to change the analyzer ranges automatically, or to report only one range despite what range the analyzer is on. You can also attach remote range control lines to the I/O module and it will control the analyzer's range. See the "Ranges" section above for more details on the ramifications of this.

1.25.2 D

The analog output module is a self contained computer that uses the Echelon Neuron chip as its processor. It gets data from the network, and it performs the necessary calculations to produce the analog output and the relay indications.

ETUP PROCEDURE

INDING TO ANALYZERS

ETTING UP ANALOG OUTPUT

ETAILS

It updates its analog output at 100 micro seconds intervals. The output circuit uses a 16-bit DAC, producing a resolution of about 0.3 mV or 1 uA.

Because it communicates to the analyzer over the network, there are inherent delays involved. If the remote range change option is used, there will be a delay of about a half of a second before the output responds to the range change request.

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

The various diagnostic measurements are made of the actual parameter measured. They are not calculated based upon the desired result, they are a direct measurement of it, as close to the reality as possible.

Thus the output voltage is measured at the output circuit just before the EMC protection devices, and the relay states are measured by inspecting the state of the second relay contact.

The output current is measured as a voltage across the output terminals. It may be reported as a current by entering the load resistance in the diagnostic screen. However this is not a direct measurement of the current.

In any case, the voltage measurements do not have the resolution of the output circuits, and so should not be used to calibrate the latter.

1.26 AUTOCALIBRATION MODULES

There are two types of Autocal modules available, a single analyzer module and a four-analyzer module. The former provides greater flexibility when dealing with a single analyzer system, but the latter is more economical in multiple analyzer systems. The single channel module also provides an analog output that is identical to the one in the Analog Alarm I/O Module, but cannot automatically change ranges.

NTRODUCTION

These modules are physically identical to the Analog Alarm I/O Module. The only difference is the software contained in the ROM.

1.26.1 T

ROUBLESHOOTING

I press Zero and the analyzer zeros off the sample…

The analyzer zero and span controls are not linked to the Autocalibration module. If you want to do an automatic calibration, enter the menus, enter

and enter

setup

press "START"'. Simply to do an automatic zero you have to select the

calibration

"START".

function in this screen, select

Auxiliary module controls...,

select the

zero gas

Autocalibration module

and the

zero operation

Expert controls and

I set a start time but the module didn't do anything…

Verify the system clock is set correctly, and verify that the start day and time you chose is in the future from the time you set it. Then wait until that time.

I want to synchronize several analyzers to calibrate at once…

and

Manual

, and press

You should use the system Autocalibration module for this. You can only synchronize the zero start times between Autocalibration modules.

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I put zero and span gases into the analyzer but the analyzers won’t calibrate…

Verify that you have set them to calibrate, not QC check in both the zero and span gas valves, and also the general parameters. Verify that the gases are correct, and the analyzers are not trying to correct so much that their calibration limit checking stops them. Also verify that your dwell times are long enough that the zero and span readings are reached.

The analyzer does funny things on span, I can't figure it out…

If the analyzer changes range due to the Autocalibration module telling it to do so, the reading will possibly change, particularly if the ranges are not themselves all calibrated. Verify that all ranges are either calibrated or that the system is setup to work on one range only If this is the case, it is safest to set all ranges to be the same, then it won't matter if you have a range change.

1.26.2 D

The System Autocal Module is identical physically to the Single Autocal Module. However it does. not provide an analog output. It can zero up to four analyzer modules simultaneously, and span any of them on any range on each of its four span gas valves.

Set it up in the same way as for the single Autocalibration module, except that for each span valve you have to choose not only which analyzer but also which range to span on.

The module's menus refer to Analyzer 1, Analyzer 2, Analyzer 3 and Analyzer 4. There is a menu available which will let you tell which analyzer is which.

1.26.3 U

Use the System Autocal Module when you want to synchronize calibrations of up to four analyzers in a system and you are using a common sample system for them all. Use the single Autocalibration module when you have just one analyzer, or when you have separate zero and span gas paths into multiple analyzers. In this case you can use multiple single Autocalibration modules in a system, and synchronize their operation. Finally you can use several single Autocalibration modules together with a system Autocalibration module and synchronize them all.

IFFERENCES BETWEEN THE SYSTEM AUTOCALIBRATION MODULE AND THE

INGLE AUTOCALIBRATION MODULE

SE OF THE SYSTEM AUTOCALIBRATION MODULE AND THE SINGLE

UTOCALIBRATION MODULE

Note

The synchronization merely synchronizes the start time of the sequence, the subsequent sections are NOT synchronized.

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

1.27 SYNCHRONIZING AUTOCAL MODULES

Autocalibration modules can be synchronized by assigning them master, slave or independent status. A Master will force any slaves in the same system to start their calibration sequence when the master does. A Slave will not perform a calibration unless the Master tell it to. An Independent module will ignore a master, and simply work on its own internal timing.

NTRODUCTION

1.27.1 B

Enter

Select the module.

Enter

Select

Edit this to MASTER, SLAVE or INDEPENDENT.

ASIC INSTRUCTIONS

Expert controls and setup

Auxiliary module setup...

General parameters...

This module's control status:

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OTES

August 1998 Rosemount Analytical 748384-BNGA Reference Manual

NALYZER VARIABLES

2.1 VERSION 2.2

This section describes the NGA analyzer variables. This description is taken from the "CSV" files that are used to build the software for each NGA module, and where conflicts exist, the "CSV" file takes precedence.

The following variables are defined in the analyzer module and are also used by the I/0 module:

CALSTAT PVACEMS CONTROL PVU GAS RNGHI GENERALSTATE RNGLO I_TIME SVCONT IOHOLDCAL SVNAME MAXRANGE TAG MINRANGE TIME_LEFT OPSTATUS VALIDITY PROCESS

AFT90

Direction Bidirectional Binding AFT90 Type 4-element floating point Value range 0.0-30 Units Seconds Description Determines the filter time constant for the primary reading. This may be

different for each range - element 1 applies to range 1 and so on.

Usage Setting this to 0 removes 0 filtering. Setting it to less than about 1 second

removes most of the median filtering, if the analyzer has any. Setting it higher will remove noise from the signal, but at the expense of response time. Those analyzers with inherently long response time, such as long cell IR analyzers, should use larger numbers. Otherwise, set this as large as is consistent with the response time you wish to obtain.

See also

AM_INPUT

Direction Input Binding None Type Enumerated Value range Analyzer specific: FID - LIGHT_FLAME; CLD- NOX_MODE,

OZONATOR_ON; Not present in NDIR or PMD modules. Units None Description Shows which functions can be controlled by an 1/0 Module's digital input Usage Used to select the operation of the 1/0 Module's digital input line. Its value

appears on the 1/0 Modules' menus that control this function. See also ST1CONT

AMBC

Direction Bidirectional Binding AMBC Type String Value range 31 characters Units None Description Describes the analyzer physical configuration (e.g. bench type). Usage This is a descriptive variable. It should not be changed unless the analyzer

hardware is changed. See also TAG

AMSN

GAS

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748384-BRosemount Analytical

NALYZER VARIABLES

AMDELAYTIME

Direction Bidirectional Binding None Type Float Value range 0-30 Units Seconds Description Delays the primary reading by this amount Usage Used to delay the output of one analyzer with respect to another, so as to

cause their responses to a gas change to be aligned in time. This is only useful for systems of analyzers.

See also

AMSERVDATE

Direction Bidirectional Binding None Type String Value range 31 characters Units None Description The in-service date Usage Manually entered when the unit is put into service. This is optional. See also AMSERVDATE

AMMFGDATE

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EFERENCE MANUAL

AMSN

Direction Bidirectional Binding AMSN Type String Value range 31 characters Units None Description The module serial number. Usage Set by the manufacturer when the module passes final test during the

manufacturing process. This should not be changed lightly! It should match the serial number on the analyzer case. If the analyzer computer board is exchanged, this value along with all others should be corrected.

See also

CURR_SENS

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NALYZER VARIABLES

CURRENTINT

Direction Output Binding None Type Enumerated Value range OFF; ON Units None Description Shows status of interference compensation for this range Usage Not used in version 2.2 or earlier. Version 2.2 analyzers do not have

the interference compensation feature.

See also

CURRENTLSTAT

Direction Output Binding CURRENTLSTAT Type Enumerated Value range DISABLED; ENABLED – 1; ENABLED - 2; ENABLED - 3; ENABLED -

4. Units None Description Shows status of linearization for the current range. Usage Used for displaying the linearization status of the current range. It is

possible to use any of the sets of linearization coefficients on a given range, as long as the upper limit of the range is within the limit of the linearizer range.

Rosemount NGA 2000 Reference Manual-Rev B Manuals & Guides

Specifications and Main Features

Frequently Asked Questions

User Manual