Campbell Scientific CVS4200 / BVS4300 Stationary Samplers - Manual (Page 16)

CVS4200 / BVS4300 Stationary Samplers
Operating temperature for CVS4200 indoor samplers is 10º to 50ºC (50º to
122ºF), adaptable down to 0ºC (32ºF) upon request. The operating temperature
for BVS4300 outdoor samplers with heater and insulation is –40º to 50ºC (–40º
to 122ºF). Without insulation and heater, the BVS4300 operating temperature
is 0º to 50ºC (32º to 122ºF).
Samples can be triggered by a variety of means. The internal clock on the
controller can be set to sample based on time/day (for example, sample every
hour). There are also a variety of external inputs that can be connected to
control sampling. Pulse count is useful for sampling after a certain number of
pulses have been reached (for example, using a rain gauge to trigger sampling).
The 4-20mA option is useful for flow-based sampling (for example, using a
flow meter to trigger sampling after a certain volume of water has passed by).
External contact is used to control the sampler from another datalogger, and is
useful when full external control is desired. Level control is the option to
choose when the application has starts and stops (for example, using a float
switch to trigger sampling when water is present, then stop sampling when the
water drops below the set level).
When sampling is initiated, liquid travels through the intake tube into the
metering chamber. The amount of water taken is set mechanically using the
liquid sensing rod and the volume control tube, which means sample accuracy
is precise every time, usually within ±2% or ±2 ml.
Once the pre-set amount has been reached, all excess liquid is purged from the
system, and the sample is dropped into a container. Sample containers range
from 500 ml (500 cc or 2 cups) wedges in discrete systems, up to 20 liters (5
gallons) containers for composite systems.
Intake tube is offered in either 9.5 mm (3/8 in) ID or 15.9 mm (5/8 in) ID.
Transport velocity varies depending on height and distance being sampled. For
most situations the sampler pulls at over 1.5 m s
–1 (5 ft s –1 ). For an in-depth
speed chart, refer to Section 6.5, Sample Transport Velocity.
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