Campbell Scientific CS470/CS471 Compact Bubbler System - Manual (Page 26)

CS470/CS471 Compact Bubbler System
• Use low capacitance, low resistance, screened cable (as fitted by Campbell
Scientific) to reach distances of several hundred meters.
• Ensure that the power ground cable has low resistance and is connected to
the same ground reference as the datalogger control ports.
• Be aware that “daisy-chaining” sensors reduces the maximum cable length
roughly in proportion to the number of sensors connected in parallel.
8.4 Measuring Multiple SDI-12 Sensors
Up to ten CS470/CS471 sensors or other SDI-12 sensors can be connected to a
single datalogger control port. Each SDI-12 device must have a unique SDI-12
address of 0 and 9, A to Z, or a to z. See Appendix D, SDI-12 Sensor Support,
for more information.
9. Maintenance
Never open the CS470/CS471 housing! There are no adjustments or control
elements inside the housing!
The CS470/CS471 itself is maintenance free. The manufacturer recommends
checking the measuring tube and bubble chamber at regular intervals and
cleaning as required. For every visit, you should do the following:
• Collect data.
• Visually inspect wiring and physical conditions.
• Check battery condition (inspect physical appearance and use a keyboard
display or laptop to view the battery voltage).
• Check all sensor readings; adjust level offsets if necessary.
• Check recent data.
• Check the bubble chamber quarterly for sand buildup and weed
infiltration. For light sand buildup, clean the bubble chamber using the
purge function, and for heavier buildup or weed infiltration, clean the
bubble chamber carefully manually (do not change the position of the
bubble chamber).
• Activate the purge function by pressing the membrane button. Pump and
check whether air bubbles rise out of the bubble chamber. If not, check
whether the bubble chamber is blocked, and/or whether the measuring tube
is leaking or blocked.
After 15 years of operation, test the measuring tube for tightness/pressure
resistance; repeat this test roughly every two years thereafter.
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