Campbell Scientific CPEC200 Closed-Path Eddy-Covariance System - Manual (Page 65)

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). The pump
will be disabled if the pump is too cold. The pump module has a heater that
turns on if pump_tmpr falls below 2°C. If the pump temperature is too low,
check the operation of the heater which is controlled by public variable
pump_heat_ON. 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. See Appendix D, Control Bits. This
value is saved only if saving all diagnostics. Its corresponding variable,
pump_heat_Avg, is saved in the averaged output tables (Flux and
Zero_Span). If the heater is on and the pump is too cold, check the ambient
temperature. The CPEC200 is rated for temperatures from −30°C to 50°C. If
the system is started in cold weather after being turned off for several hours, it
may take up to 50 minutes to warm up to operating temperature.
The pump will also be disabled if the pump is too warm (above 55°C). The
pump module has a fan that turns on if pump_tmpr rises above 50°C. The fan
will stay on until the pump temperature falls below 45°C. If the pump
temperature is too high, check the operation of the fan which is controlled by
public variable, pump_fan_ON. 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. See Appendix D, Control Bits. This
value is saved only if saving all diagnostics. Its corresponding variable
pump_fan_Avg is saved in the averaged output tables (Flux and Zero_Span).
If the fan is on and the pump temperature is too high, check the ambient
temperature. The CPEC200 is rated for ambient temperatures from –30°C to
50°C.
Bit 4: Pipeline Buffer Depth
If the remainder of diag_cpec (after subtracting the numeric value for higher
bits that are set) is greater than 7, this means that bit 4 of diag_cpec is set. To
decode other diagnostic bits, subtract 8 from diag_cpec and compare the
remainder to the bit values below.
The CPEC200 CRBasic program runs in pipeline mode. This allows
processing tasks to fall behind, but ensures that measurements always happen
at the proper time. Generally, it is acceptable for processing tasks to fall
behind occasionally, unless they include real-time control functions. For
example, pipeline mode allows the flux calculations, which occur at the end of
each half-hour averaging period, to take more time than is available in a single
measurement scan interval. Processing instructions may be delayed by a few
scans until the extra processing is completed. In this case, the actual
measurements occur on time and are saved in a buffer until they can be
processed. See the CR3000 Micrologger Operator’s Manual for more
information on pipeline mode.
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