Campbell Manufacturing LIQUID LEVEL DB1 Manual De Usuario

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DB1 Liquid Level Measurement Sensor 
fluctuates between 5 and 15 ft (2.2 and 6.5 psi), set the pressure regulator 
above 7 psi (read 10 psi) to ensure adequate pressure. 
Open the nitrogen bottle valve, set the pressure regulator, and adjust the 
nitrogen flow by adjusting the two needle valves.  The suggested bubble rate is 
1 to 3 bubbles/seconds.  The nitrogen gas bottle, regulator, and tubing 
(Campbell P/N 7567) are available from any welding supply store.  Use 
common sense when installing pressure lines, checking for leaks, moisture, 
kinks, etc. in the lines. 
The DB1 does not have a mechanism to stop the flow of gas through the two 
submerged tubes so gas will be flowing constantly.  This is very effective in 
reducing the growth of biomass in the tubes, which could otherwise reduce or 
block the flow of gas.  If you wish to conserve gas, you can install a 12 Vdc 
solenoid valve between the gas bottle and the DB1 manifold and use the 
SW12V port on the datalogger to open the valve just prior to a measurement.  
This will result in slower consumption of nitrogen but may result in biomass 
build-up in the mouth of the tubes. 
4.  Wiring 
Wiring connections for the CR800, CR850, CR1000, and CR10(X) 
dataloggers are shown in Figure 3.  The channel numbering in the wiring 
diagram matches the channel usage in the program examples.  The pressure 
transducer within the DB1 has four conductors (white, green, red, black).  The 
white lead connects to the high side and the green lead connects the low side of 
any analog channel (e.g. 1H and 1L).  The red lead connects to any excitation 
channel and the black lead connects to any analog ground channel. 
The three relay cable assemblies have three conductors for each valve.  The 
green wires connect to control ports C1 (Valve #1), C2 (Valve #2), and C3 
(Valve #3) as used in the program example that follow.  The red wires connect 
to 12 volts, and the black wires connect to ground.  The cable assemblies have 
been provided with extra lead length to enable the user to cut the cables to 
length to accommodate different size enclosures.