Campbell Scientific CPEC200 Closed-Path Eddy-Covariance System - Manual (Page 46)

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).
Public variable valve_status gives information on the temperature of the valve
module and scrub module, if used. If temperature control is disabled
( valveTctl_ON = False), valve_status will report Valves are in standby mode
(temperature control is disabled). If temperature control is enabled
( valveTctl_ON = True), valve_status will report Valves are ready if the valve
module and scrub module are within their operating temperatures. Otherwise,
it will report whether the valve module or scrub module temperature is either
too high or too low.
6.3.1.2 Starting the sequence
When the valve module and scrub module, if used, reach their operating
temperature range, and valve_status reports Valves are ready, you may start
the zero/span sequence. If either module is outside of its operating range when
you attempt to initiate the sequence, the sequence will not start, and an error
message will be written to the message_log table and displayed in public
variable latest_note.
To manually start the automatic zero/span sequence, set STARTsequence =
True. This will cause the zero/span sequence to run (see Section 6.2,
Automatic Zero and Span, for details on setting up the sequence). The
keyboard display has a menu to make this easy if there is onsite access to the
datalogger. Navigate the menus as follows:
Manual Zero/Span → Run Zero/Span Seq
The zero/span sequence can also be initiated by simply setting the public
variable STARTsequence directly. At the conclusion of a manually initiated
zero/span sequence, the CPEC200 will automatically resume EC mode. It will
automatically disable temperature control of the valve module and scrub
module.
Running the zero/span sequence manually will write results to the Zero_Span
table, just as if the sequence was run automatically by the system. This record
of the zero/span process is another advantage of using the sequence instead of
full manual control.
6.3.1.3 Stopping the sequence
Normally the zero/span sequence will run to completion, and the CPEC200
will automatically disable valve temperature control and return to EC mode.
To manually stop the sequence while it is running, turn the pump on by setting
pump_ON = True. This will stop the sequence, turn the valves off, disable
valve temperature control, turn the pump on, and return to EC mode.
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