INSTRUCTION MANUAL CPEC200 Closed-Path Eddy-Covariance System Revision: 7/14 C o p y r i g h t © 2 0 1 3 - 2 0 1 4 C a m p b e l l S c i e n t i f i c , I n c .
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Assistance Products may not be returned without prior authorization. The following contact information is for US and international customers residing in countries served by Campbell Scientific, Inc. directly. Affiliate companies handle repairs for customers within their territories. Please visit www.campbellsci.com to determine which Campbell Scientific company serves your country. To obtain a Returned Materials Authorization (RMA), contact CAMPBELL SCIENTIFIC, INC., phone (435) 227-9000.
Precautions DANGER — MANY HAZARDS ARE ASSOCIATED WITH INSTALLING, USING, MAINTAINING, AND WORKING ON OR AROUND TRIPODS, TOWERS, AND ANY ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS, CROSSARMS, ENCLOSURES, ANTENNAS, ETC. FAILURE TO PROPERLY AND COMPLETELY ASSEMBLE, INSTALL, OPERATE, USE, AND MAINTAIN TRIPODS, TOWERS, AND ATTACHMENTS, AND FAILURE TO HEED WARNINGS, INCREASES THE RISK OF DEATH, ACCIDENT, SERIOUS INJURY, PROPERTY DAMAGE, AND PRODUCT FAILURE.
Table of Contents PDF viewers: These page numbers refer to the printed version of this document. Use the PDF reader bookmarks tab for links to specific sections. 1. Introduction ................................................................. 1 2. Cautionary Statements ............................................... 1 3. Initial Inspection ......................................................... 2 4. Overview ...................................................................... 2 4.
Table of Contents 5.4 Configure the Program ...................................................................... 28 5.4.1 System Configuration Variables................................................. 28 5.4.2 Compile Switches ....................................................................... 32 5.5 Verify Proper Operation .................................................................... 32 6. Zero and Span ...........................................................33 6.1 6.2 6.
Table of Contents G. CPEC200 Scrub Module Installation, Operation and Maintenance .................................................. G-1 G.1 G.2 G.3 G.4 Theory of Operation ........................................................................ G-1 Scrub Module Specifications .......................................................... G-2 Installation ....................................................................................... G-2 Maintenance ....................................................
Table of Contents G-3. Interior of CPEC200 scrub module with tubing and cover removed ....................................................................................... G-4 G-4. Empty bottle showing the top (on the right with spring) and bottom (left) caps ......................................................................... G-5 H-1. Four screws holding filter assembly inside CPEC200 pump module enclosure ......................................................................... H-1 H-2.
CPEC200 Closed-Path Eddy-Covariance System 1. Introduction The CPEC200 is a closed-path, eddy-covariance (EC) flux system used for long-term monitoring of atmosphere–biosphere exchanges of carbon dioxide, water vapor, heat, and momentum. This complete, turn-key system includes a closed-path gas analyzer (EC155), a sonic anemometer head (CSAT3A), datalogger (CR3000), sample pump, and optional valve module for automated zero and span.
CPEC200 Closed-Path Eddy-Covariance System o o o 3. Do not overtighten the tube fittings. Consult Appendix E, Using Swagelok® Fittings, for information on proper connection. The CPEC200 power source should be designed thoughtfully to ensure uninterrupted power. If needed, contact a Campbell Scientific applications engineer for assistance. Retain all spare caps and plugs as these are required when shipping or storing the CPEC200 system.
CPEC200 Closed-Path Eddy-Covariance System 4.1.1.2 EC100 Electronics The EC100 electronics module (FIGURE 4-2) controls the EC155 and CSAT3A. It is housed in its own enclosure and must be mounted within 3 m of the sensors. FIGURE 4-2. EC100 electronics module 4.1.1.3 CPEC200 Enclosure The CPEC200 enclosure (FIGURE 4-3) houses the CR3000 datalogger, control electronics, the optional valve module, and communications and power terminals.
CPEC200 Closed-Path Eddy-Covariance System 4.1.1.4 CPEC200 Pump Module The pump module (FIGURE 4-4) uses a small, low-power diaphragm pump to draw air through the EC155 sample cell. The pumping speed is automatically controlled to maintain the volumetric flow at the setpoint (3 to 7 LPM). The pump module is temperature controlled to keep the pump in its operating temperature range of 0°C to 55°C.
CPEC200 Closed-Path Eddy-Covariance System FIGURE 4-5. CR3000 datalogger 4.1.2.2 NL115 or CFM100 Storage Module The datalogger saves data onto a CompactFlash® (CF) memory card (FIGURE 4-7) via an optional NL115 or CFM100 card module (FIGURE 4-6). Either module will provide data storage. The NL115 has the added capabilities that are available with the Ethernet interface. FIGURE 4-6. NL115 (left) and CFM100 (right) The CPEC200 can be ordered with either of the storage modules factory installed.
CPEC200 Closed-Path Eddy-Covariance System 4.1.2.3 CPEC200 Valve Module The optional CPEC200 valve module (FIGURE 4-8) is housed in the CPEC200 enclosure and is used to automate zero and CO2 span checks, and automatically perform a field zero and field CO2 span on a user-defined interval. Field H2O span requires a dewpoint generator and cannot be automated because the dewpoint generator is a laboratory instrument. Therefore, H2O spans must be performed manually.
CPEC200 Closed-Path Eddy-Covariance System FIGURE 4-9. CSAT3A sonic anemometer head 4.1.2.5 Barometer The EC100 is always configured with an EC100 basic barometer. However, an EC100 enhanced barometer is available as an option. The decision to upgrade to the enhanced barometer is largely dependent on the specific site and environmental constraints for a given site. In general, the enhanced barometer provides overall greater accuracy, but may not be a necessary upgrade for many applications.
CPEC200 Closed-Path Eddy-Covariance System pump module is similar to the ENC10/12 enclosure. The same mounting options are available and outlined below: • • • • • Triangular tower (UT10, UT20, or UT30) Tripod mast 3.8 cm (1.5 in) to 4.8cm (1.9 in) diameter Tripod leg (CM106 or CM106K tripod only) Large pole 10.2 cm (4.0 in) to 25.4 cm (10.0 in) diameter No mounting bracket Consult the ENC10/12, ENC12/14, ENC14/16, ENC16/18 Instruction Manual, available at www.campbellsci.
CPEC200 Closed-Path Eddy-Covariance System Minimize the length of these tubes to reduce the amount of equilibration time required after the zero or CO2 span cylinder is selected. One long tube is required to connect the valve module to the EC155, and two short tubes are required to connect the zero and CO2 span cylinders to the valve module. Preswaged tube assemblies (pn 21823-L) are available for this purpose.
CPEC200 Closed-Path Eddy-Covariance System available from Campbell Scientific. For more details about this card, see Application Note 3SM-F, PC/CF Card Information, available from www.campbellsci.com. USB Memory Card Reader/Writer: The USB memory card reader/writer (pn 17752) is shown in FIGURE 4-11. It is a single-slot, high-speed reader/writer that allows a computer to read a memory card.
CPEC200 Closed-Path Eddy-Covariance System 4.1.5 Replacement Parts Intake Filter: The EC155 intake filter (FIGURE 4-12) will become clogged over time and must be replaced. The default replacement part is pn 26072. It is a 2.5-cm (1.0-in) diameter, sintered stainless steel disk filter with a 20 µm pore size encased in a molded Santoprene™ shell. An alternative 40 µm filter (pn 28698) is also available. Use a 40 µm filter if the default 20 µm filter clogs long before the EC155 optical windows become dirty.
CPEC200 Closed-Path Eddy-Covariance System FIGURE 4-14. Humidity indicator card EC155 Replacement Chemical Bottles: The EC155 has two small bottles filled with chemicals to remove CO2 and water vapor from the inside of the sensor head. If replacement bottles are needed, two bottles are included with pn 26511. Diaphragm Pump: The pump module for the CPEC200 includes a small double-head diaphragm pump with a brushless DC motor.
CPEC200 Closed-Path Eddy-Covariance System 4.2 Theory of Operation The CPEC200 is used for long-term monitoring of atmosphere–biosphere exchanges of carbon dioxide, water vapor, heat, and momentum. This complete, turn-key system includes a closed-path gas analyzer (EC155), a sonic anemometer head (CSAT3A), datalogger (CR3000), sample pump, and an optional valve module for automated zero and span. 4.2.
CPEC200 Closed-Path Eddy-Covariance System 4.2.2 CSAT3A Sonic Anemometer Head The CSAT3A, as shown in FIGURE 4-17, is an ultrasonic anemometer sensor head for measuring wind speed in three dimensions. It shares integrated electronics, the EC100 electronics, with the EC155 gas analyzer. It is similar to the sensor head for the CSAT3 sonic anemometer, with the primary difference being that the CSAT3 can be used as a standalone anemometer because it includes independent electronics.
CPEC200 Closed-Path Eddy-Covariance System For the three-valve version, the inputs are: • • • Zero CO2 Span 1 H2O Span For the six-valve version, the inputs are: • • • • • • Zero CO2 Span 1 CO2 Span 2 CO2 Span 3 CO2 Span 4 H2O Span The CPEC200’s zero and CO2 span inlets are not bypass equipped, meaning that they flow only when selected. This allows the zero and CO2 span tanks to be continuously connected for automatic, unattended operation.
CPEC200 Closed-Path Eddy-Covariance System The CPEC200 valve module includes a heater and a fan to keep the valves within their operating range of 0°C to 60°C. The valve heater turns on/off at 2°C. The valve fan turns on at 50°C and stays on until the valve temperature drops to 48°C. To conserve power, temperature control is active just prior to and during the time when valves are in use. If the valves cannot be maintained within the temperature range, the valves are disabled.
CPEC200 Closed-Path Eddy-Covariance System The outlet of the pump connects the Exhaust fitting on the bottom of the pump module enclosure. This fitting has a screen to prevent insects or debris from entering when the pump is off. 4.3 Specifications System Operating temperature: Input voltage: Power: –30° to +50°C 10.5 to 16.0 Vdc 12 W (typical), 35 W (max, at cold startup) System enclosure Dimensions: Weight basic system: CR3000: CFM100/NL115: Three-valve module: Six-valve module: 52.1 x 44.5 x 29.
CPEC200 Closed-Path Eddy-Covariance System • • • • 5.1 Small, flat-tip screwdriver (included with EC100 and CPEC200) Large, flat-tip screwdriver (included with EC100) Sledgehammer (to drive grounding rod into the ground) 3/16-in hex-key wrench (included with CM250 leveling mount) Mounting 5.1.1 Support Structure The CPEC200 system has four major components that must be mounted to a user-provided support structure.
CPEC200 Closed-Path Eddy-Covariance System back on the leg of a CM110 tripod in FIGURE 5-1, but they may also be mounted on a vertical pipe, triangular tower, or large-diameter pole, depending on the site requirements and the mounting options ordered. CPEC200 Enclosure EC100 Electronics Pump Module FIGURE 5-1. CPEC200 enclosure, pump module, and EC100 mounted to legs of CM110-series tripod For the EC100 and the system enclosure, open the sealed bag containing the desiccant packs and humidity card.
CPEC200 Closed-Path Eddy-Covariance System CM210 Crossarm-toPole Bracket CM202 Crossarm FIGURE 5-2. CM210 mounting bracket on a tripod mast The EC155 gas analyzer and CSAT3A sonic anemometer head are mounted on the end of the crossarm using the CM250 leveling mount and the CPEC200 mounting platform, as shown in FIGURE 5-3. Adjust the tilt of the mounting platform to level the CSAT3A. For more details see instructions in the EC155 CO2 and H2O Closed-path Gas Analyzer manual.
CPEC200 Closed-Path Eddy-Covariance System 5.2 Plumbing FIGURE 5-4 shows the basic plumbing configuration of a CPEC200 including the cylinders required for zero and span operations. Zero Air Tubing Pump Tubing Analyzer Tubing CO2 Span Gas Tubing Pump Module Cable FIGURE 5-4. Plumbing connections 5.2.1 Pump Module Connect the EC155 to the pump module, see FIGURE 5-5. If the EC155 is within 15 m (50 ft) of the pump module, 3/8-in OD tubing, such as pn 26506, is recommended.
CPEC200 Closed-Path Eddy-Covariance System FIGURE 5-5. Connecting pump tube from EC155 analyzer to pump module 5.2.2 Zero/Span The CPEC200 can perform automated zero (CO2 and H2O) and CO2 span of the EC155. In most cases the user must supply cylinders of zero air and CO2 span gas with appropriate regulators. If the user has chosen the optional CPEC200 scrub module, then no cylinder of zero air is required.
CPEC200 Closed-Path Eddy-Covariance System NOTE Make sure there are no leaks in the regulators or the connections to the valve module. For automatic operation, the tank shutoff valves are left continuously open. A plumbing leak could cause the contents of the tank to be lost. NOTE When inlets are not in use, replace the Swagelok® plugs to keep the system clean. Connect the valve module’s Analyzer outlet to the Zero/Span fitting on back of the EC155 analyzer.
CPEC200 Closed-Path Eddy-Covariance System FIGURE 5-6. Enclosure and tripod grounded to a copper-clad grounding rod 5.3.2 EC Sensor Cables Ensure the EC100 is not powered. Connect the EC155 gas analyzer head, EC155 sample cell, and CSAT3A sonic anemometer head to the EC100 electronics. FIGURE 5-7 shows the electrical connections described in this section. For more details see the EC155 CO2 and H2O Closed-Path Gas Analyzer Manual. EC155 Analyzer Cable EC155 Sample-cell Cable CSAT3A Cable FIGURE 5-7.
CPEC200 Closed-Path Eddy-Covariance System Wire the SDM communications cable (CABLE4CBL-L) between the EC100 and the CPEC200 enclosure as shown in FIGURE 5-8, FIGURE 5-9, and FIGURE 5-10. TABLE 5-1 shows the color scheme of the SDM wires. TABLE 5-1.
CPEC200 Closed-Path Eddy-Covariance System EC100 Power Cable EC100 SDM Cable FIGURE 5-9. Wiring to EC100 electronics Power Cable to +12Vdc Power Supply (off) Power Cable to EC100 SDM Cable to EC100 FIGURE 5-10.
CPEC200 Closed-Path Eddy-Covariance System 5.3.3 Pump Module Cable Ensure the CPEC200 system is not powered, and connect the pump module cable to the bottom of the CPEC200 system enclosure. 5.3.4 Apply Power The CPEC200 requires a 10.5 to 16.0 Vdc power source. Its average power consumption is 12 W typical but will be slightly higher at cold temperatures, especially at startup in cold weather.
CPEC200 Closed-Path Eddy-Covariance System 5.4 Configure the Program A CR3000 datalogger program Cpec200_vx_x.cr3 is included with the CPEC200 system. If the CPEC200 was ordered with the CR3000 factory installed, the CPEC200 is shipped with the program installed. A copy of the program is found on the CPEC200 Support CD (pn 26857) or can be downloaded from www.campbellsci.com. The CPEC200 program uses both constants and variables to customize the behavior of the system for a particular installation.
CPEC200 Closed-Path Eddy-Covariance System BATT_DEADBAND: This variable, along with BATT_LOWLIMIT, determines when the CPEC200 will restart after an automatic power shutdown. The CPEC200 will not restart until the supply voltage BattVolt reaches at least BATT_LOWLIMIT + BATT_DEADBAND. The purpose of the deadband function (the gap between the shutdown voltage and the turn-on voltage) is to protect the CPEC200 from repeated power cycles when the battery voltage is very near the limit.
CPEC200 Closed-Path Eddy-Covariance System PUMP_SETPT: Variable PUMP_SETPT determines the volumetric flow rate at which the pump will draw the air sample through the EC155 sample cell. PUMP_SETPT must be 3 to 9. The default setting is 7.0 LPM. In tall tower applications where decreased frequency response is acceptable, lowering the flow rate may be desirable as it will prolong the life of the intake filter.
CPEC200 Closed-Path Eddy-Covariance System CAL_FLOW_SETPT: Determines the rate at which the zero or CO2 span gas will flow. The path the gas takes is from the cylinder, through the valve module to the EC155 analyzer, and out the end of the EC155 intake. The CPEC200 valve module has a proportional control valve to actively control the flow of zero and span gas. This flow rate can be changed by changing the value of public variable CAL_FLOW_SETPT. The default for zero and span gas flow is 1.
CPEC200 Closed-Path Eddy-Covariance System CHECK_SPAN2: Check the gas analyzer span against CO2 gas number 2 (requires the 6-valve module). CHECK_SPAN3: Check the gas analyzer span against CO2 gas number 3 (requires the 6-valve module). CHECK_SPAN4: Check the gas analyzer span against CO2 gas number 4 (requires the 6-valve module). 5.4.2 Compile Switches The CPEC200 program defines four constants that are used as compile switches. The function of these constants are defined below.
CPEC200 Closed-Path Eddy-Covariance System Public variable mode_status describes the basic operating state of the CPEC200. Verify mode_status = Normal EC mode. See Appendix A, CPEC200 Diagnostics, for further information. Public variable cpec_status gives an overall status for the entire system. If there are no problems detected, cpec_status will report CPEC is OK. See Appendix A, CPEC200 Diagnostics, for further information.
CPEC200 Closed-Path Eddy-Covariance System In addition to identifying the most appropriate use of manual versus automatic and remote versus onsite calibration, there is one additional option to consider: whether to simply check the zero/span, or to set the zero/span. Checking the zero/span allows the user to track the performance of the EC155, apply gain and offset corrections in post processing, and decide when to actually set the zero/span.
CPEC200 Closed-Path Eddy-Covariance System TABLE 6-1. Automatic Zero/Span Sequence valve_number 6.
CPEC200 Closed-Path Eddy-Covariance System To initiate a zero/span sequence manually, first turn on the temperature control for the valves by setting valveTctl_ON = True. The keyboard display’s menu makes this easy if there is onsite access to the datalogger. Navigate the menus as follows: Manual Zero/Span → Temperature Control The temperature control can also be enabled by setting the public variable directly (using LoggerNet, for example).
CPEC200 Closed-Path Eddy-Covariance System 6.3.2 Full Manual Control of Zero and Span In some cases it may be more appropriate to run the zero/span under full manual control. This allows the user to decide how much time is required for the zero or span gas to reach equilibrium, or to perform additional status checking. It also allows the H2O to be spanned. The keyboard display has menus to facilitate manual zero/span control for users that are onsite. Navigate: Manual zero/span → Manual Control 6.3.2.
CPEC200 Closed-Path Eddy-Covariance System Set valve_number to ZeroAir (1). If onsite, look at the LEDs on the valve module to confirm the selected valve is now active. Verify valve_status reports Valve flow is OK. If not, check the value of valve_flow and troubleshoot as needed. Verify cpec_status reports CPEC is OK. If not, troubleshoot as needed. NOTE There is no automatic error checking in full manual mode, so diagnostics must be checked manually. Watch the values of CO2 and H2O.
CPEC200 Closed-Path Eddy-Covariance System The keyboard display has menus to facilitate manual zero control for users that are onsite. Navigate: Manual zero/span → Manual Control → H2O Span Set valve_number = H2Ospan. If onsite, look at the LEDs on the valve module to confirm the selected valve is now active. Verify valve_status reports Valve flow is OK. If not, check the value of valve_flow and troubleshoot as needed. NOTE When the H2Ospan valve is selected, the CPEC200 does not control the flow.
CPEC200 Closed-Path Eddy-Covariance System 7.1 Enclosure Desiccant Check the humidity indicator card in the mesh pocket in the CPEC200 system enclosure door and the EC100 enclosure door. The humidity indicator card has three colored circles that indicate the percentage of humidity (see FIGURE 4-14). Desiccant packets inside the enclosure should be replaced with fresh packets when the upper dot on the indicator begins to turn pink.
CPEC200 Closed-Path Eddy-Covariance System 7.4 EC155 Chemical Bottles If more than one year has passed since replacing the desiccant/scrubber, or if zero-and-span readings have drifted excessively, the desiccant/scrubber bottles (pn 26511) within the EC155 analyzer head should be replaced as detailed in the EC155 CO2 and H2O Closed-Path Gas Analyzer Manual. 8. Repair The CPEC200 is designed to give years of trouble-free service with reasonable care.
CPEC200 Closed-Path Eddy-Covariance System 42
Appendix A. CPEC200 Diagnostics A.1 Overview CPEC200 diagnostic information is available to the user in any of three different formats: status text strings, status Boolean variables, and diagnostic flags encoded as binary bits in integer variables. With these multiple avenues of accessing the information, the CPEC200 diagnostics provide user-friendly real-time troubleshooting, statistics on individual error conditions, and a compact format for final storage tables. A.
Appendix A. CPEC200 Diagnostics If the CPEC200 program is configured for valve operation there are more possibilities: • • • • Normal EC mode: Pump is on Manual Zero/Span mode: Pump is off Starting Zero/Span sequence: This message persists normally for only one scan indicating the zero/span sequence has been triggered, either automatically or manually, but has not yet begun.
Appendix A. CPEC200 Diagnostics • • • • • • • because the EC100 is not powered, or the SDM cable from the datalogger to the EC100 is not connected. ERROR: No EC155 detected - Check EC155 connections to EC100 is displayed if diag_irga = −1 (all diagnostic bits are set). This usually means the EC155 sensor head is not connected to the EC100. If bit 9 of diag_irga is set, this indicates the EC155 has been powered down.
Appendix A. CPEC200 Diagnostics • This usually means the CSAT3A sensor head is not connected to the EC100. ERROR: Sonic problem - Check diag_sonic is displayed when a bit is set in diag_sonic. This usually means the sonic path is blocked. If there is no obvious reason for the problem, such as water on the face of a transducer, contact Campbell Scientific for assistance. pump_status Public variable pump_status gives the status of the pump and is based on the state of several variables.
Appendix A. CPEC200 Diagnostics If the program is configured to use the valve module (constant VALVE_MODULE = True), but the valves are not being used (valve_number = 0), there are several possible values for valve_status that relate to the temperature of the valve module. valve_status also depends on the temperature of the optional scrub module if it is installed. See notes on bits 2 and 1 for more information on valve module and scrub module temperature control.
Appendix A. CPEC200 Diagnostics • • • pressure sensor is used to infer flow, and Section 6.3.2, Full Manual Control of Zero and Span, for more detailed information about how the pressure offset is measured. ERROR: Valve flow is NAN is displayed if press_offset is not zero and valve_flow = NAN (see the note above for the case when press_offset = 0). This indicates a problem with the valve flow measurement. See notes on bit 3 for details.
Appendix A. CPEC200 Diagnostics notes on bit 8 and on irga_status, which may give additional information about the IRGA problem. pump_flow_OK Boolean variable pump_flow_OK = True if the pump flow (pump_flow) is within 10% of the setpoint PUMP_SETPT. It is set to False if it is outside this range. The PUMP_SETPT check is performed continuously and pump_flow_OK is set accordingly.
Appendix A. CPEC200 Diagnostics scrub_tmpr_OK Boolean variable scrub_tmpr_OK is defined only if the CPEC program is configured to use a scrub module. See Appendix G, CPEC200 Scrub Module Installation, Operation and Maintenance, for details. If scrub_tmpr_OK = True, the scrub module temperature (scrub_tmpr) is within its operating range (5°C to 50°C). It is set to False if it is outside this range. This check is performed continuously and Boolean variable scrub_tmprOK is set accordingly.
Appendix A. CPEC200 Diagnostics TABLE A-1.
Appendix A. CPEC200 Diagnostics The purpose of the deadband (the gap between the shutdown voltage and the turn-on voltage) is to protect the CPEC200 from repeated power cycles when the battery voltage is very near the shutdown limit. There are two possible values for cpec_status when BattVolt_OK = False. If the battery voltage is below the shutdown limit, cpec_status will report ERROR: Battery voltage is too low. In this case, the battery must be recharged before the CPEC200 will resume normal operation.
Appendix A. CPEC200 Diagnostics 3. If diag_irga is a number greater than zero, this indicates the EC100 has detected a problem. Troubleshoot per the EC155 CO2 and H2O Closed-Path Gas Analyzer Manual. If diag_irga is zero, this means the EC100 has detected no errors with the EC155. However, the EC100 does not check for low signal levels. Check the values of CO2_signal and H2O_signal. These variables give a relative signal level at the EC155 detector. These variables should be approximately 1.
Appendix A. CPEC200 Diagnostics respond by increasing pump_control. This should increase the speed of the pump and allow pump_flow to rise to the setpoint. Conversely, if the flow is above the setpoint the CPEC200 will adjust pump_control downward until the flow matches the setpoint. If pump_control = 0, this indicates the CPEC200 has turned the pump off.
Appendix A. CPEC200 Diagnostics time during the averaging period. A value of 0 indicates a pump temperature problem during the entire time. To continue troubleshooting a problem with the pump temperature, check the measured pump temperature, pump_tmpr. If it is NAN, this indicates a problem with the temperature measurement. Make sure the pump module cable is connected to the “Pump Module” connector on the bottom of the CPEC200 system enclosure. Next, compare pump_tmpr to the operating range (0°C to 55°C).
Appendix A. CPEC200 Diagnostics Conversely, processing tasks that affect real-time control functions may be adversely affected if there are processing delays. The control algorithms that adjust the pumping speed and valve flow are processing tasks. If the datalogger processing is delayed these algorithms will use “old” measurements. This will cause the pump speed or valve flow to be poorly controlled.
Appendix A. CPEC200 Diagnostics If the value of valve_flow = NAN, this indicates a problem with the valve flow measurement. The valve flow is inferred from the pressure drop in the sample cell as described in Section 4.2.3, Valve Module. Check the value of valveControl. This variable determines the size of the opening of a proportional control valve, from 0 (fully closed) to 1.0 (fully open). This proportional control valve can be described as an electrically operated needle valve.
Appendix A. CPEC200 Diagnostics generator and the Valve Module inlet. Make sure there is no tee in this connection (see Section 5.2.2, Zero/Span). Finally, check the flow setting of the dewpoint generator. 3. If the Zero Air valve (1) is selected and a scrub module is used, the flow is controlled by the scrub module. The scrub module has a pump to push the zero air through the valve module to the IRGA. The CPEC200 fully opens the flow control valve by setting valveControl = 1.
Appendix A. CPEC200 Diagnostics table ts_data, the state of fans and heaters is encoded into variable ControlBits to conserve memory space. See Appendix D, Control Bits. This value is saved only if saving all diagnostics. Its corresponding variable valve_heat_Avg is saved in the averaged output tables (Flux and Zero_Span). If the heater is on and the valve module is too cold, check the ambient temperature. The CPEC200 is rated for temperatures from −30°C to 50°C.
Appendix A. CPEC200 Diagnostics Next, compare scrub_tmpr it to the operating range (5°C to 50°C). The scrub module will be disabled if it is too cold. The scrub module has a heater that turns on if scrub_tmpr falls below 7°C. If the scrub module temperature is too low, check the operation of the heater which is controlled by public variable scrub_heat_ON.
Appendix B. Public Variables Some of the variables in the CPEC200’s CRBasic program are included in the Public table. These public variables may be displayed or edited with a keyboard display or PC. Other program variables are hidden from the user to reduce clutter in the Public table. Many of these public variables are saved in the output tables. Some of the public variables allow the user to set the operation of the system or to give diagnostic information.
Appendix B. Public Variables TABLE B-1.
Appendix B. Public Variables TABLE B-1.
Appendix B. Public Variables TABLE B-1.
Appendix B. Public Variables TABLE B-1.
Appendix B.
Appendix C. Output Variables The CPEC200 program stores data in several output tables. Details are given for each table. ts_data The primary output table is ts_data table which gives time-series data. This table stores each sample of the raw CPEC200 data (ten records per sec). The CPEC200 program stores this table in multiple files on the memory card, with a new file started each day at midnight. The size of these daily files depends on the compile flags.
Appendix C. Output Variables TABLE C-1.
Appendix C. Output Variables The next eleven values (wind_speed through flux samples) give several values associated with the online fluxes. The number of samples included in these calculations (flux_samples) includes only those samples for which all of the data (sonic, irga, and pump) are OK. The next twenty-two values (Ts_stdev through Tc_Uz_cov) are the covariance matrices of the various flux components.
Appendix C. Output Variables TABLE C-2.
Appendix C. Output Variables TABLE C-2.
Appendix C. Output Variables at seven records per sequence, and sequences run every hour). The CPU has storage allocated for 500 records (3 days). The zero_span table is defined only if VALVE_MODULE = True. As a result, only the last five values, associated with the scrub module, are optional depending on the SCRUB_MODULE compile switch. The value of the compile switches as shown in TABLE C-3 depends on the constants as described in Section 5.4.2, Compile Switches.
Appendix C. Output Variables TABLE C-3.
Appendix C.
Appendix C. Output Variables Compile Switches. The code shown in the table can be either V, S, or a combination of two of the codes. V is defined if VALVE_MODULE = True S is defined if SCRUB_MODULE = True and VALVE_MODULE = True TABLE C-4.
Appendix C. Output Variables TABLE C-4.
Appendix C. Output Variables TABLE C-5.
Appendix C.
Appendix D. Control Bits For diagnosing a problem using data saved in the output table, ts_data, the state of fans and heaters is encoded into variable ControlBits to conserve memory space. A user unfamiliar with converting a decimal number to binary may find it convenient to use a decimal-to-binary converter that can be found on the Internet. Alternately, follow the step-by-step troubleshooting instructions as a guide through the conversion process.
Appendix D. Control Bits If ControlBits is greater than 255, this indicates bit 9 of ControlBits is set. This means the sample pump heater is on. To decode other temperature control bits, subtract 256 from ControlBits and compare the remainder to the bit values below. If ControlBits is greater than 127, this indicates bit 8 of ControlBits is set. This means the valve module fan is on. To decode other temperature control bits, subtract 128 from ControlBits and compare the remainder to the bit values below.
Appendix E. Using Swagelok® Fittings This appendix gives a few tips on using Swagelok® tube fittings. For more information, consult your local Swagelok® dealer or visit their web site at www.swagelok.com. General Notes: • Do not use fitting components from other manufacturers – they are not interchangeable with Swagelok® fittings. • Do not attempt to use metric fittings. Six mm is very close to 1/4 in, but they are not interchangeable.
Appendix E. Using Swagelok® Fittings First-time assembly, metal tubing: Extra care is needed to avoid overtightening brass fittings when used with metal tubing. These notes apply to reducers and port connectors as well as metal tubing. NOTE No insert is required with metal tubing. 1. Do not remove the nuts and ferrules from the fitting. Simply insert the tube into the assembled fitting until it bottoms out. 2. Rotate the nut finger tight. 3.
Appendix E. Using Swagelok® Fittings Tubing inserts Inserts are recommended for use in plastic tubing. These inserts become permanently attached to the tubing at the first assembly, so spare inserts may be needed for replacing the ends of tubing. FIGURE E-1. Swagelok® insert TABLE E-2. Dimensions and part numbers for Swagelok® inserts Tubing OD (in) Tubing ID (in) Swagelok® pn CSI pn 1/4 1/8 B-405-2 15834 1/4 0.
Appendix E. Using Swagelok® Fittings Plugs Swagelok® plugs are used to plug a fitting when its tube is disconnected. It is strongly recommended to plug all fittings to keep them clean. Spare plugs may be needed if they become lost or damaged. FIGURE E-3. Swagelok® plug TABLE E-4.
Appendix F. Installing the AC/DC Power Adapter Kit The AC/DC Power Adapter Kit is configurable within the CPEC200 system enclosure to allow the CPEC200 to be powered from AC mains power. A peripheral mounting kit (pn 16987) is necessary to install the AC/DC adapter into the CPEC200 system enclosure. The mounting kit includes a bracket, a Velcro® strap, and the necessary nuts and screws. The following steps describe the mounting procedure. 1.
Appendix F. Installing the AC/DC Power Adapter Kit FIGURE F-2. Power supply in mounting bracket 4. Tighten the Velcro® strap to secure the power supply to the mounting bracket (FIGURE F-3). FIGURE F-3. Secured power supply in mounting bracket 5. NOTE F-2 Connect the pigtail connector to the DIN rail connectors as shown in (FIGURE F-4). The wire with the white strip is +12 V.
Appendix F. Installing the AC/DC Power Adapter Kit FIGURE F-4. Connections for the power supply in CPEC200 enclosure 6. NOTE If the AC/DC adapter kit was ordered with a detachable power cord, remove the enclosure feedthrough cap, insert the end of the power cord, and plug it into the AC/DC adapter. If a long AC power cord is required, have a certified electrician connect the field-wireable plug that is supplied with the kit, to a user-supplied cord. 7.
Appendix F.
Appendix G. CPEC200 Scrub Module Installation, Operation and Maintenance The CPEC200 Scrub Module provides a stream of air that has been scrubbed of CO2 and H2O and is used for zeroing the EC155. The module is housed in a fiberglass enclosure that can generally be mounted to the same structure as the CPEC200 system enclosure. The enclosure is shown in FIGURE G-1, and the specifications can be found in Appendix G.2, Scrub Module Specifications. FIGURE G-1. CPEC200 scrub module G.
Appendix G. CPEC200 Scrub Module Installation, Operation and Maintenance Pump Control The pump is turned on automatically when the Zero Air valve is selected. The pump has a maximum flow rate of approximately 2.0 LPM and a maximum pressure rise of approximately 90 kPa. Scrub Pump Outlet Pressure The measured outlet pressure of the pump is reported in public variable scrub_press. This pressure will normally be 3 to 20 kPa when it is running.
Appendix G. CPEC200 Scrub Module Installation, Operation and Maintenance Edit the CPEC200 CRBasic program to set constant SCRUB_MODULE = True and recompile. The CPEC200 program will add the appropriate variables. It will control the temperature of the scrub module whenever it controls the temperature of the valve module. It will turn on the scrub module pump whenever the Zero Air valve is selected.
Appendix G. CPEC200 Scrub Module Installation, Operation and Maintenance NOTE Disconnecting this tube ensures the bottles are not pressurized when the cover is removed. The scrub module has been designed to require this tube to be disconnected before removing the cover as a safety precaution. 4. Loosen the four thumbscrews (shown in FIGURE G-2) and remove the cover plate to gain access to the bottles (FIGURE G-3). Note that the thumb screws are captive; they remain attached to the cover plate.
Appendix G. CPEC200 Scrub Module Installation, Operation and Maintenance FIGURE G-4. Empty bottle showing the top (on the right with spring) and bottom (left) caps 10. Remove the spent molecular sieve in accordance to local ordinances and the manufacturer’s Material Data Safety Sheet. 11. Refill the bottle with new molecular sieve and replace the top cap (the cap with the spring). 12. Replace freshly filled bottle in the open position on the right side of the enclosure. 13.
Appendix G.
Appendix H. CPEC200 Pump Replacement H.1 Introduction A properly maintained CPEC200 system will exceed the lifetime of the system’s pump. This section provides step-by-step instructions for the user to replace the system pump (pn 26402), rather than needing to return the pump enclosure to Campbell for replacement. H.2 Removal To remove a CPEC200 pump, carry out the following steps: 1. NOTE Place the pump module on a horizontal surface.
Appendix H. CPEC200 Pump Replacement FIGURE H-2. Upright filter unit in enclosure 4. With the filter assembly removed from the CPEC200 pump module enclosure, remove the six #4 screws (FIGURE H-3) from the pump assembly. If these screws become lost or damaged, replace them with pn 488. FIGURE H-3. Location of #4 screws of pump assembly 5. H-2 Once the screws are removed, fold back the pump assembly from the shell bottom as shown in FIGURE H-4.
Appendix H. CPEC200 Pump Replacement FIGURE H-4. Exposed CPEC200 pump assembly 6. Remove pump connector from the pump electronics (FIGURE H-5). FIGURE H-5. Location of pump connector in CPEC200 pump electronics 7. Gently lift the pump assembly from foam, leaving the tubes attached. Turn it over and remove the two self-tapping #6 screws that attach the pump to the metal box, as shown in FIGURE H-6. If these screws become lost or damaged, replace them with pn 13535.
Appendix H. CPEC200 Pump Replacement FIGURE H-6. Self-tapping screws attaching pump to metal box 8. Cut the blue (inlet) and red (outlet) tubing on each side of the pump behind the barbed connector as shown in FIGURE H-7. FIGURE H-7. Location of cuts to remove pump assembly from tubing 9. Remove the pump from the assembly. H.3 Installation To reinstall a CPEC200 pump, carry out the following steps: 1.
Appendix H. CPEC200 Pump Replacement FIGURE H-8. Inlet and outlet tubing reconnected to pump FIGURE H-9. Pump side with inlet and outlet tubing connected 2. NOTE Reattach the pump to metal box with two self-tapping #6 screws on the back of the pump module electronics plate (FIGURE H-6). Be careful not to pinch the fan wires under the pump and do not overtighten screws. 3. Reattach the pump connector to the pump electronics (FIGURE H-5). 4.
Appendix H. CPEC200 Pump Replacement FIGURE H-10. Proper positioning of CPEC200 in shell cover NOTE 5. Hold the pump assembly securely to the shell cover while replacing the shell cover to the shell bottom. Make sure the fan does not slide back out of its hole in the foam. Fasten the shell cover in place with the six #4 screws (see FIGURE H-3). 6. Reconnect the tubing to the inlet and outlet of the filter assembly (see step 2 of removal and refer to FIGURE H-3).
Campbell Scientific Companies Campbell Scientific, Inc. (CSI) 815 West 1800 North Logan, Utah 84321 UNITED STATES www.campbellsci.com • info@campbellsci.com Campbell Scientific Centro Caribe S.A. (CSCC) 300 N Cementerio, Edificio Breller Santo Domingo, Heredia 40305 COSTA RICA www.campbellsci.cc • info@campbellsci.cc Campbell Scientific Africa Pty. Ltd. (CSAf) PO Box 2450 Somerset West 7129 SOUTH AFRICA www.csafrica.co.za • cleroux@csafrica.co.za Campbell Scientific Ltd.
