AP200 CO2/H2O Atmospheric Profile System
Complete, Integrated System
Preprogrammed and low power
weather applications water applications energy applications gas flux and turbulence applications infrastructure applications soil applications

Overview

The AP200 is a complete, integrated CO2 and H2O atmospheric profile system. It measures carbon dioxide (CO2) and water vapor (H2O) concentration from up to eight intakes, which are normally spaced along the height of a tower to give a vertical profile. The AP200 is often used in conjunction with an eddy-covariance system to measure the storage term and give a more complete measure of the surface gas exchange.


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Benefits and Features

  • Fully integrated system
  • Requires only 13 W (average at 25°C and 12 Vdc)
  • Contains a Campbell Scientific CR1000X Measurement and Control Datalogger
  • Automatically performs CO2 zero and span
  • Automated temperature and pressure control
  • Data logger program included

Images

<dl><dt>Typical AP200 Installation</dt> <dd>1-27693 Heated Sample Intake Assemblies (from 4 up to 8)</dd> <dd>2-9922 20 AWG Power Cable</dd> <dd>3-28547 AP200 System Enclosure</dd> <dd>4-15702 Tubing</dd> <dd>5-Zero/Span Tanks and Regulators (not included)</dd> <dd>6-Instrument Tower (sold separately)</dd></dl>

Detailed Description

Measurements

Primary:

  • CO2 concentration at each intake
  • H2O concentration at each intake
  • System diagnostic word

Secondary:

  • Sample flow rate
  • Sample cell pressure
  • Sample cell temperature
  • Other control variables

Note: Contact the Micromet Group at Campbell Scientific for questions or updates regarding the datalogger program.

Specifications

System Enclosure
Operating Temperature -30° to +45°C
Power Requirements
  • 10 to 16 Vdc (voltage)
  • 13 W (average power at 25°C)
    Average power varies from 12.5 W above +35°C to 22.5 W at -30°C.
  • 3.75 A (45 W) maximum power (cold startup)
Dimensions 52.1 x 44.5 x 29.7 cm (20.5 x 17.5 x 11.7 in.)
Weight
  • 15.9 kg (35 lb) for AP200 base model
  • 1 kg (2.3 lb) for LI-850
  • 272 g (10 oz) for CR1000KD
  • 154 g (5.4 oz) for CFM100/NL116

Pump Module
Pump Type Dual-head diaphragm pump with a brushless dc motor
Mounting Mounted in an insulated, temperature-controlled box inside system enclosure
Control Pumping speed is automatically controlled to maintain the pump inlet pressure at the set point
Maximum Pumping Speed 9.0 liters per minute (LPM)
Pressure Sensor Range 15.0 to 115.0 kPa
Heater 8.0 W (turns on/off at 2°C)
Warm-up Time ~50 min (from -30° to +2°C)
Fan 0.7 W (turns on at 50°C and off at 45°C)

Valve Manifold
Mounting Mounted inside system enclosure
Inlets Eight air sample inlets plus one inlet for zero, one inlet for CO2 span, and one inlet for H2O span
Connections 0.25-in Swagelok
Mass Flow Sensor 0 to 1.0 standard liters per minute (SLPM)
Heater 8.0 W (turns on/off at 5°C)
Warm-up Time ~20 min (from -30° to +4°C)
Fan 0.7 W (turns on at 45°C and off at 43°C)

Intake Assembly
Filter 1.0-in diameter, sintered stainless-steel disk filter, 10-micron pore size
Orifice Heater 2 kohm (0.07 W at 12 Vdc)
Mixing Volume 750 mL
Sample Connection 0.25 in. Swagelok
Number of Connections for Heater Cable Entry Seals 3 (1 in, 2 out)
Cable Diameter for Heater Cable Entry Seals 2.8 to 6.6 mm (0.11 to 0.26 in.)
Wire Diameter for Heater Cable Screw Terminals 26 to 12 AWG
Wire Stripping Length for Heater Cable Screw Terminals 5.0 mm (0.2 in.)
Screw Tightening Torque for Heater Cable Screw Terminals 0.4 N•m
Orifice Inside Diameter 0.178 mm (0.007 in.)
Dimensions 31 x 12.5 x 19 cm (12 x 5 x 7.5 in.)
Weight 1.4 kg (3.1 lb)

Downloads

AP200 CR1000 Program v.2.01 (31.3 KB) 12-01-2021

AP200 CR1000(X) Program.

Compatible with the LI-850.

Note: For those with the LI-840 contact Campbell Scientific for compatible code.

View Revision History

Device Configuration Utility v.2.34 (48.7 MB) 09-04-2026

A software utility used to download operating systems and set up Campbell Scientific hardware. Also will update PakBus Graph and the Network Planner if they have been installed previously by another Campbell Scientific software package.

Supported Operating Systems:

Windows 11 or 10 (Both 32 and 64 bit)

View Revision History

Frequently Asked Questions

Number of FAQs related to AP200: 41

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  1. Why does the AP200 system use so much power at lower temperatures?

    The LI-840A uses a heater to maintain its sample cell at +50°C. Therefore, it consumes a lot more power at lower temperatures. Below 0°C, the valve heater also requires some power to keep the valves warm.

  2. How many intake assemblies are needed on an AP200?

    The number of intakes required at a site depends on the characteristics of the canopy. For example, the canopy’s height and density directly affect the change in CO2 and H2O concentrations. Order enough intakes to accurately profile these concentration changes. The AP200 may be ordered with anywhere from four to eight intake assemblies.

  3. Why should AP200 intakes be numbered from bottom to top?

    Numbering this way helps reduce the time skew between measurements of the intakes. To illustrate this, consider a parcel of air that moves through the intake tubes at approximately 0.5 m/s. If the longest tube is 60 m longer than the shortest tube, its travel time is two minutes longer than the shortest tube. Sampling from the shortest tube first means that the air samples enter each tube at the same time.

  4. If fractional tube sizes are not available, can 6 mm tubing be used instead on the AP200?

    The AP200 uses ¼ in. tube fittings. Tubing with a 6 mm outer diameter (OD) will not fit, unless a 6 mm to ¼ in. reducer is used on each end of each tube.

  5. How often should the intake filters be changed on an AP200?
    This depends on the site. Replace the filters when the sample intake flow is 75% of the flow with clean filters. As an example, long-term testing in Logan, UT, shows that filters need to be changed about once per year. If the air at a site is dirtier, then the filters will need to be replaced more often.
  6. Can an already purchased LI-840A be used in an AP200? If so, what is necessary to install it and set it up?

    Yes. The AP200 can be ordered without an LI-840A so that a facility may use one it already owns. All the required mounting hardware and plumbing fittings are shipped with the AP200. The installation requires no tools and is very easy. The installation instructions are provided in the AP200 Instruction Manual. The AP200 will automatically configure the LI-840A.

  7. If greater precision than what the LI-840A can provide is desired, can another analyzer, such as the LI-7000, be used instead?
    No. The AP200 is designed to work only with an LI-840 or an LI-840A.
  8. Why would CAL_TIMEOFFSET ever be set to a non-zero value?

    A non-zero value can be used to perform a zero/span on an interval that is not synchronized to midnight (for example, every three hours starting at 0100 hrs).

  9. Can the AP200 be used to measure horizontal advection?

    Possibly. For example, to measure advection because of a drainage flow on sloping terrain, an AP200 system could be deployed with two towers, upstream and downstream along the slope, with four intakes on each tower.

  10. Do the intake tubes on the AP200 have to be the same length?

    No.

Visit the FAQ Library

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