Campbell Scientific CPEC200 Closed-Path Eddy-Covariance System - Manual (Page 100)

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.
Scrub Pump Temperature
The temperature of the scrub pump is reported in public variable scrub_tmpr.
The operating range of the pump is 5°C to 50°C. If the pump temperature is
outside this range, the CPEC200 will disable the pump. The pump module has
a heater (drawing 8W while operating) that turns on if the pump temperature
falls below 7°C. If the CPEC200 is started at cold temperature, it may take up
to 20 minutes to warm the pump module (from –30°C to 5°C). When it
reaches 7°C the heater will cycle on/off as needed to maintain this temperature.
The pump module has a fan (drawing 0.7W while operating) that turns on if the
pump temperature rises above 45°C. The fan will stay on until the pump
temperature falls below 40°C.
G.2 Scrub Module Specifications
Operating temperature: − 30 to 50°C
Power consumption i
Quiescent: 0 W
With pump on: 2 W
With heater on: 8 W
With fan on: 0.7 W
G.3 Installation
There are numerous mounting options for the scrub module including tripod
(mast or leg), tower, or pole. Enclosure mounts are specified when ordering
the CPEC200 Scrub Module and mounting the module is accomplished in the
same way as mounting other CPEC200 enclosures as described in Section 5.1,
Mounting.
Connect the scrub module cable to the CPEC200 system enclosure, receptacle
marked Scrub Module. Remove the Swagelok ® plugs from the inlet and
outlet and store them in the mesh pocket in the door. Install the Swagelok ® nut
with screen on the Ambient Air inlet. Connect a 1/4-in OD tube from scrub
module to valve module on the Zero inlet. Remove the desiccant pack from its
plastic bag and place the pack in the mesh pocket.
i The typical average power consumption is generally negligible in a CPEC200 system
because it is used for a short time each day.
G-2