Campbell CPEC300, Руководство по эксплуатации продукта

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CPEC300/306/310 Closed-Path Eddy-Covariance Systems
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4.11.4 CPEC300-Series Pump Module
The pump module for the CPEC300-series systems, pulls air through the
system and exhausts it through the Exhaust fitting on the bottom of the
enclosure. It uses a small double-head diaphragm pump with a brushless DC
motor. This pump includes a speed control input and a tachometer to measure
the actual pumping speed. It is mounted in an insulated, temperature-controlled
box located inside the weather-tight fiberglass enclosure. The pump module
includes a large filter cartridge to dampen the pressure fluctuations from the
pump and to protect the pump from particulates or debris.
If the pump fails, a replacement pump is available (see Section 4.10 ,
Replacement Parts
(p. 17)
). See Appendix L ,
CPEC300 Series Pump
Replacement
(p. L-1)
, for instructions on replacing the pump. The filter cartridge
in the pump module is unlikely to clog over the lifetime of any CPEC300-series
system.
The following sections describe operating parameters of the pump.
Pump Speed:
The pump tachometer is measured, converted to volumetric flow
rate, and reported in public variable pump_flow_raw . A CPEC300-series
system will set the value of public variable pump_flow_duty_cycle to a value
between 0 (off) and 1 (full speed) to adjust the pump’s speed as needed to
match pump_flow_raw to the setpoint flow pump_flow_set_pt .
Pump_flow_set_pt is a system configuration variable.
Pump Inlet Pressure: The measured inlet pressure of the pump is reported in
public variable pump_press . This pressure will normally be slightly lower
(~1 kPa) than the EC155 sample cell pressure due to the pressure drop in the
pump tube.
Pump Temperature: The temperature of the pump module is reported in
public variable pump_tmpr . The operating range of the pump is 0 to 55 °C. If
the pump temperature is outside this range, the CPEC300-series system will
disable the pump. The pump module has a heater (drawing 8 W while
operational) that turns on if the pump temperature falls below 2 °C. If the
CPEC300-series system is started at cold temperature, it may take up to 50
minutes to warm the pump module (from –30 to 0 °C). When it reaches 2 °C
the heater will cycle on/off as needed to maintain this temperature.
The pump module has a fan (drawing 0.7 W while operational) that turns on if
the pump temperature rises above 45 °C. The fan will stay on until the pump
temperature falls below 40 °C.
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.