Campbell Scientific CPEC200 Closed-Path Eddy-Covariance System - Manual (Page 63)

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 CO
2
and H
2
O
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 1.0 for
clean windows. As the windows become dirty, these signals will drop. If
either of these signals is below 0.80, irga_OK will be set to False and the
EC155 source and detector windows should be cleaned per the EC155 CO
2
and
H
2
O Closed-Path Gas Analyzer Manual.
Bit 7: Sonic Anemometer
If the remainder of diag_cpec (after subtracting the numeric value for higher
bits that are set) is greater than 63, this means that bit 7 of diag_cpec is set. To
decode other diagnostic bits, subtract 64 from diag_cpec and compare the
remainder to the bit values below.
Bit 7 of diag_cpec is equivalent to sonic_OK = False. It indicates there is a
problem with the sonic anemometer. Troubleshoot as follows:
1. Check the value of diag_sonic. If it is NAN, this indicates the
CR3000 is not receiving data from the EC100. Check the SDM cable
connection and make sure power is supplied to the EC100.
2. If diag_sonic is −1, this indicates the EC100 does not recognize that a
CSAT3A sonic head is connected. Make sure the CSAT3A cable is
connected to the EC100. (Remove power from the EC100 before
connecting or disconnecting the CSAT3A).
3. If diag_sonic is a number greater than zero, check that the sonic path
is not blocked. If no obvious reason for the problem (such as water on
the face of a transducer) can be found, contact Campbell Scientific for
assistance.
Bit 6: Pump Flow
If the remainder of diag_cpec (after subtracting the numeric value for higher
bits that are set) is greater than 31, this means that bit 6 of diag_cpec is set. To
decode other diagnostic bits, subtract 32 from diag_cpec and compare the
remainder to the bit values below.
Bit 6 of diag_cpec indicates the pump flow is not at the setpoint. To confirm
the problem, verify that public variable pump_flow_OK = False. This
variable is set to true if the value of pump_flow matches PUMP_SETPT
within 10%. It is set to false if it is outside this range. If the pump is turned off
this check is still performed, but is not relevant. ( pump_flow_OK = False, but
bit 6 diag_cpec will not be set.)
If the value of pump_flow = NAN, this indicates a problem with the pump
speed measurement. Contact Campbell Scientific for assistance.
If the flow is not at the setpoint, check the value of pump_control. This
variable controls the speed of the pump, from 0.0 (off) to 1.0 (full speed). In
normal operation, when the flow falls below the setpoint, the CPEC200 will
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