LI-COR LI-870 Using Manual Download Page 16

Section 2. Using the LI-870

In the Smart Chamber and LI-8250 interface, you can see when your LI-870 optical
bench has stabilized when the dot in the upper-left portion of any screen by the
time stamp is green. If the bench is not stabilized, this dot will be red.

You can also visualize the optical bench temperature and pressure from the

Home

Page

of the Smart Chamber or LI-8250 interface to assess whether they have sta-

bilized. After connecting to the Smart Chamber or LI-8250, from the

Home Page

,

select

Click to Set

. In the

Select a variable...

window that opens, open the LI-870

list, and you can select

Cell Temperature

and

Cell Pressure

.

These variables will now be in the grid on the

Home Page

. Click them again to

graph the values live.

2-4

Using the LI-870 CO₂/H₂O Analyzer

Summary of Contents for LI-870

Page 1: ...Using the LI 870 CO2 H2O Analyzer...

Page 2: ......

Page 3: ...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 Innovation...

Page 4: ...s document contains proprietary information which is protected by copyright All rights are reserved No part of this document may be photocopied reproduced or translated to another language without pri...

Page 5: ...tion Cautions must be observed to avoid damage to your equipment Note Notes contain important information and useful tips on the operation of your equipment CE Marking This product is a CE marked prod...

Page 6: ...ly from unsorted municipal waste The fol lowing applies to users in European countries This product is designated for separate collection at an appropriate collection point Do not dispose of as househ...

Page 7: ...number 2 3 Storing the LI 870 2 5 Section 3 Troubleshooting Smart Chamber or LI 8250 software not recognizing LI 870 3 1 Unable to Zero or Span the Instrument 3 2 Instrument Reports 50 ppm CO2 or Mea...

Page 8: ...General A 1 CO2 Measurements A 1 H2O Measurements A 1 Appendix B Equations summary Appendix C Warranty vi...

Page 9: ...LI 870 Refer to the Smart Chamber and LI 8250 manuals for additional information What s what If you have just taken delivery of your LI 870 check your packing list to ensure the following items have...

Page 10: ...cable and tubing assembly is included with the LI 870 to connect the LI 870 with the Smart Chamber or LI 8250 Multiplexer This assembly includes l Sealed USB A to USB B cable part number 392 17654 l...

Page 11: ...cal Bench Cleaning Kit 1 9980 066 USB A to USB B Unsealed 6 meter 1 392 06652 Software The LI 870 can be calibrated using the LI 830 LI 850 user interface software which is available from the LI COR s...

Page 12: ...Section 1 Overview of the LI 870 1 4 Using the LI 870 CO H O Analyzer...

Page 13: ...First attach each end of the cable assembly to the LI 870 The USB B end of the USB A to USB B cable is attached to the LI 870 while the USB A end is attached to the Smart Chamber or LI 8250 Note Only...

Page 14: ...designed to only power the LI 870 CO2 H2O Analyzer Accessory Only use the power cable supplied with the LI 870 cable assembly P N 9982 010 and do not attempt to power any other devices with the Smart...

Page 15: ...I 870 will boot up as soon as power is supplied from the chamber The optical bench should be allowed to warm up prior to taking measurements The LI 870 optical bench is temperature and pressure contro...

Page 16: ...he optical bench temperature and pressure from the Home Page of the Smart Chamber or LI 8250 interface to assess whether they have sta bilized After connecting to the Smart Chamber or LI 8250 from the...

Page 17: ...f the season or when you return to the lab or desk after taking your last meas urements you should perform a measurement or two with the Smart Chamber to allow dry ambient air to flow through your cha...

Page 18: ...Section 2 Using the LI 870 2 6 Using the LI 870 CO H O Analyzer...

Page 19: ...vice with no further steps needed Simply expand the LI 870 drop down in the Connections menu of the Measurement Settings page of the Smart Chamber or LI 8250 software select your instrument serial num...

Page 20: ...urther instructions If the light is blinking but you still cannot identify your device through the Smart Chamber or LI 8250 software check your USB cable for damage Is there dust or debris in the cabl...

Page 21: ...optical bench and replace the O rings Note that the images included in this section were taken from a prototype LI 870 The wiring and plumb ing in your instrument may appear slightly different Warning...

Page 22: ...the plate and foam and set aside The insulated optical bench will now be visible 3 Gently lift the optical bench out of the insulating foam and remove the cable connectors from the source and detector...

Page 23: ...d detector to remove any residue Warning Do not use abrasive cleansers Abrasive cleaners can irreparably damage the gold plating on the optical path source or detector 8 Inspect the hose barbs and tub...

Page 24: ...ce for the LI 870 is through the Smart Chamber or LI 8250 software you may also connect your LI 870 to the LI COR LI 830 850 soft ware to view data and for user calibration After downloading and insta...

Page 25: ...LI 870 soil applications you will likely only the use the software for instrument calibration User calibration If the instrument is not measuring as expected or if you have disassembled the optical b...

Page 26: ...e performance of your instrument If you do not have the proper equipment to span the analyzer it is best to leave it alone Setting the CO2 zero Always perform the zero first To set the zero you ll nee...

Page 27: ...l slightly above the upper limit of what you expect to measure For example if you are measuring near ambient levels choose a span gas that is near 400 ppm CO2 as opposed to 18 000 ppm Similarly if you...

Page 28: ...precision of the analyzer The process is exactly the same as setting the primary span only you ll enter a different concentration and click Span2 CO2 Recovering from a bad zero or span If your attemp...

Page 29: ...Measurement principle Non dispersive infrared NDIR Operating pressure range 50 to 110 kPa Flow rate nominal 0 75 liters min 1 Power Requirements Input voltage 10 17 VDC 2 A max After warmup without pu...

Page 30: ...Appendix A Specifications A 2 Using the LI 870 CO H O Analyzer...

Page 31: ...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 B 2 is a span corrected absorptance and g P is the pressure cor...

Page 32: ...W mmol mol 1 is computed from B 8 where fw x is a third order polynomial whose coefficients are given on the cal ibration sheet B 9 CO2 Equations The measurement of CO2 is a bit more complicated than...

Page 33: ...irical pressure correction function gc depends on CO2 absorptance and pressure When P Po gc 1 When P Po B 11 where a 1 10158 b 6 1217E 3 c 0 266278 d 3 69895 and z is the asymp totic value of absorpta...

Page 34: ...rument for CO2 concentrations near ambient At higher concentrations the value decreases We capture this behavior with an empirical relationship equation B 19 B 19 Where z is from equation B 12 and bw...

Page 35: ...g bw to 1 When bw 1 h c 1 everywhere Also to avoid com putational problems underflows 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 equ...

Page 36: ...absoprtance T is com puted from B 22 LI 870 computes Sw0 from equation B 23 where is averaged over five seconds B 23 where B 24 The instrument retains the following values which are used for subseque...

Page 37: ...s Sc0 from equation B 28 where and are averaged for 5 seconds B 27 B 28 where B 29 Note that B 30 We need cT to compute but cT depends on We resolve this by using an approximation equation B 31 instea...

Page 38: ...mputes new values for both Sc0 and Sc1 First it measures a new and computes a new c from equation B 29 Then it uses these plus the retained values c1 and c1 from the previous normal span to compute B...

Page 39: ...maged 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 Inc at...

Page 40: ...y whether 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 cust...

Page 41: ......

Page 42: ...l 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 Cambri...

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