LI-COR LI-830 Скачать руководство пользователя страница 35

A-1

Using the LI-830 and LI-850 Gas Analyzers

Appendix A.

Equation Summary

The LI-830 and LI-850 compute CO

2

concentrations using an equation of the form

A-1

where

c

is concentration,

f

() is the calibration function,

α

" is the absorptance,

g

(

α

,

P

) is the pressure correction,

S

(

α

) is the span, and

T

is the temperature (°C) of

the gas in the cell, typically 51.5 °C. Absorptance is computed from

A-2

α

' is a span corrected absorptance, and g(

α

',

P

) is the pressure correction.

A-3

S

(

α

) is the span function, and raw absorptance

α

is computed from

A-4

where

V

and

V

o

are the raw detector sample and reference readings, and

Z

is the

zeroing parameter.

Span is a linear function of absorptance.

A-5

Содержание LI-830

Страница 1: ...Using the LI 830 and LI 850 Gas Analyzers...

Страница 2: ......

Страница 3: ...ada envsales licor com Regional Offices LI COR Biosciences GmbH Siemensstra e 25A 61352 Bad Homburg Germany Phone 49 0 6172 17 17 771 envsales gmbh licor com LI COR Biosciences UK Ltd St John s Innova...

Страница 4: ...ts reserved Publication Number 984 17190 Created on Tuesday September 4 2018 Notes on Safety This LI COR product has been designed to be safe when operated in the manner described in this manual The s...

Страница 5: ...e limits for a Class A computing device pursuant to Subpart J of Part 15 of FCC rules which are designed to provide a reasonable protection against such interference when operated in a commercial envi...

Страница 6: ...iv...

Страница 7: ...he terminal strip power connectors 1 7 Installing device drivers 1 8 Storing the gas analyzer 1 8 Section 2 Configuring the gas analyzer Overview of the software 2 1 Configuring graphs 2 2 Logging dat...

Страница 8: ...the primary CO2 span 4 2 Setting the secondary CO2 span 4 3 Setting the H2O zero and spans LI 850 only 4 3 Recovering from a bad zero or span 4 3 Cleaning the optical bench 4 4 Replacing a fuse 4 6 A...

Страница 9: ...in the following resources All are available from www licor com env support Select the LI 830 and LI 850 Analyzer Application software Required to configure the instrument through a graphical interfa...

Страница 10: ...ent will continue to operate with a low battery but expect a corresponding decline in performance l Alarm indicators illuminate if an alarm threshold has been crossed See Using alarms on page 2 8 l RS...

Страница 11: ...nlet and outlet 2 9861 036 Bev a line IV plastic tubing 3 6 meter roll 1 222 01824 Air filters 2 9967 008 Quick connect straight unions 2 300 03123 Cleaning kit 1 9980 066 3 Source and detector cleani...

Страница 12: ...before operating the LI 830 or LI 850 Failure to use a filter will cause contamination of the optical bench Retrieve an air filter and tubing from the accessories kit Cut a 5 to 10 cm piece of tubing...

Страница 13: ...5 Connect with the gas analyzer Start the software Click the Connection button in the upper right of the display Select your instru ment from the list set the data rate then click Connect Data will po...

Страница 14: ...se to help identify which terminal is which Terminal Label Description 1 12 30 VDC Voltage In 12 30 VDC 2 GND Ground 3 High Alarm High Alarm 4 GND Ground 5 Low Alarm Low Alarm 6 GND Ground 7 V OUT 2 V...

Страница 15: ...ost localities glob ally input 100 to 240 VAC 50 to 60 Hz output 12 VDC 2 5 amps You may need to install different blades from the outlet adapter kit to fit your wall outlets PUS H OP EN LOCK N Americ...

Страница 16: ...are installed you should see LI COR 8x0 under Ports COM LPT Storing the gas analyzer When you are done using the gas analyzer follow these practices to be sure that it is ready to use the next time y...

Страница 17: ...epends upon the instrument software which can be down loaded from the LI COR technical support web site www licor com env support Overview of the software After connecting the software presents you wi...

Страница 18: ...toscale or Fixed Scale With Fixed Scale you can set the min imum and maximum value for each variable displayed X Axis With Continuous checked the graph will display all of the data from the time you c...

Страница 19: ...will be included in the data file header l Field delimiter Choose between a space tab or semi colon delimited text file l Log rate seconds How often a value is recorded This can be 0 5 1 2 3 4 5 10 o...

Страница 20: ...4 20 mA 1 pin 13 on the terminal strip l DAC 2 configures V Out 2 pin 7 and 4 20 mA 2 pin 11 on the terminal strip Optimizing the DAC resolution When configuring the analog outputs keep in mind that t...

Страница 21: ...20 000 ppm range the data output over the DACs will have lower resolution left If the DACs are configured to output data over a narrower range for example 0 to 10 000 ppm as shown on the right the da...

Страница 22: ...om a current output 0 to 500 ppm range Unlike the voltage outputs which are 0 to 2 5 or 0 to 5 V the current outputs are from 4 to 20 mA Therefore the range is always 16 20 4 and the offset is always...

Страница 23: ...ater The heater should be enabled to maintain the optical bench tem perature Normally the optical bench will be about 51 4 C If you disable the heater the instrument will not perform as specified Pres...

Страница 24: ...dband High Deadband 500 Low alarm activated when CO2 300 ppm On 300 Low alarm deactivated when CO2 350 ppm Deadband 50 High alarm activated when CO2 700 ppm On 700 High alarm deactivated when CO2 600...

Страница 25: ...2 or H2O with the LI 850 Alarms can be set for one or the other not both 2 Configure the High Alarms l The ON settings is the high level at which the alarm is activated l The OFF setting is the level...

Страница 26: ...the optical cell has reached the operating temperature of about 50 C regardless of the setting If the cell temperature drops below 50 C the instrument will disable the pump temporarily until the cell...

Страница 27: ...ing the jack but can power it on using the terminal strip you probably have a blown power jack fuse l If the opposite is true you probably have a blown terminal strip fuse l If you can t power it usin...

Страница 28: ...ent measures 50 ppm or the measurements are going between neg ative and positive values or just simply not making any sense the optical source may have failed or be in the midst of failure Contact tec...

Страница 29: ...r concentration measurements more than lower ones Setting the CO2 zero Always perform the zero first To set the zero you ll need either a tank of dry air that is free of CO2 or a CO2 scrubbing chemica...

Страница 30: ...ear ambient levels choose a span gas that is near 400 ppm CO2 as opposed to 18 000 ppm Similarly if you are measuring concentrations near 15 000 ppm CO2 a span gas with 100 ppm would not be ideal 4 Af...

Страница 31: ...con centrations of water vapor rather than CO2 Caution Setting the zero and span incorrectly for either CO2 or H2O will adversely impact the performance of your instrument If you do not have the prop...

Страница 32: ...screws Loosen each of the screws until the top cover is free of the bottom If your instrument has a display carefully rotate the top cover out of the way without straining the cable and then unplug t...

Страница 33: ...f the hose barbs are dirty remove them and clean them with rubbing alcohol or soapy water Use caution Do not scratch the hose barbs because scratches may cause leaks 8 Inspect the O rings If they are...

Страница 34: ...till have the problem and you ll be out of spare fuses After identifying and solving the problem that caused the fuse to blow replace the fuse 1 Open the case Loosen each of the six top cover screws u...

Страница 35: ...ance g P is the pressure correction S is the span and T is the temperature C of the gas in the cell typically 51 5 C Absorptance is computed from A 2 is a span corrected absorptance and g P is the pre...

Страница 36: ...n W mmol mol 1 is computed from A 8 where fw x is a third order polynomial whose coefficients are given on the cal ibration sheet A 9 CO2 Equations The measurement of CO2 is a bit more complicated tha...

Страница 37: ...pirical pressure correction function gc depends on CO2 absorptance and pressure When P Po gc 1 When P Po A 11 where a 1 10158 b 6 1217E 3 c 0 266278 d 3 69895 and z is the asymp totic value of absorpt...

Страница 38: ...t for CO2 concentrations near ambient At higher concentrations the value decreases We capture this behavior with an empirical relationship equation A 19 A 19 Where z is from equation A 12 and bw is th...

Страница 39: ...ws overflows and division by zero we constrain the argument c when computing h c to be 0 1 c z c 0 1 is typically equivalent to about 600 ppm Calibration Equations The following equations describe the...

Страница 40: ...A 24 The instrument retains the following values which are used for subsequent sec ondary spans A 25 Secondary Span H2O LI 850 only When the secondary span command for H2O is received the instrument c...

Страница 41: ...depends on We resolve this by using an approximation equation A 31 instead when computing equation A 30 A 31 The instrument retains the following values which are used for subsequent sec ondary spans...

Страница 42: ...uation A 29 Then it uses these plus the retained values c1 and c1 from the previous normal span to compute A 34 Given the new span slope Sc1 it updates the span offset Sc0 by equation A 28 A 8 Using t...

Страница 43: ...ppm H2O measurements LI 850 only Measurement range 0 to 60 mmol mol 1 Accuracy Better than 1 5 of reading Calibration drift Drift at 0 mmol mol 1 0 003 mmol mol 1 per C Span drift at 10 mmol mol 1 0 0...

Страница 44: ...esolution 16 bits across user specified range Power requirements Input voltage 12 30 VDC After warmup without pump 0 3 A 12 VDC 3 6 W average After warmup with pump 0 4 A 12 VDC 4 6 W average During w...

Страница 45: ...on 400 200 px monochrome Power consumption 200 W Displayed variables CO2 reading H2O reading LI 850 only optical bench tem perature and pressure Specifications subject to change without prior notice D...

Страница 46: ...rument You may need to set the communication parameters on your computer or your terminal emulator program The RS 232 port is configured as Data Terminal Equipment DTE with no hardware handshaking It...

Страница 47: ...or damaged by act of God or other casualty 4 The purchaser whether it is a DISTRIBUTOR or direct customer of LI COR or a DISTRIBUTOR S cus tomer packs and ships or delivers the instrument to LI COR In...

Страница 48: ...ether included by this contract or by law are limited to the time period of this warranty which is a twelve month period commencing from the date the instru ment is shipped to a user who is a customer...

Страница 49: ......

Страница 50: ...al Offices LI COR Biosciences GmbH Siemensstra e 25A 61352 Bad Homburg Germany Phone 49 0 6172 17 17 771 envsales gmbh licor com LI COR Biosciences UK Ltd St John s Innovation Centre Cowley Road Cambr...

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