User Manual

223 Delmhorst Cylindrical Soil Moisture Block
7.2.1.2 Edlog
The generalized Edlog programming sequence follows:
ACTIVATE MULTIPLEXER/RESET INDEX
For the CR10(X) and CR23X, use Edlog instruction Do (P86) to set
the port high. For the 21X and CR7, use Edlog instruction Set
Port(s) (P20) to set the port high.
BEGIN MEASUREMENT LOOP
Use Edlog instruction Beginning of Loop (P87)
CLOCK PULSE AND DELAY
With the CR23X and CR10(X) the clock line is connected to a
control port. Instruction Do (P86) with the pulse port command
(71 – 78) pulses the clock line high for 10 ms. Instruction Excitation
with Delay (P22) can be added following the Do (P86) to delay an
additional 10 ms.
MEASURE SENSOR AND CALCULATE RESISTANCE
See Section 7.2.2, Excite and Measure the 223, and Section 7.2.3,
Calculate Sensor Resistance.
END MEASUREMENT LOOP
Use Edlog instruction End (P95).
DEACTIVATE MULTIPLEXER
For the CR10(X) and CR23X, use Edlog instruction Do (P86) to set
the port low. For the 21X and CR7, use Edlog instruction Set Port(s)
(P20) to set the port low.
7.2.2 Excite and Measure the 223
The sensor is excited and measured using the BrHalf instruction in CRBasic or
Instruction 5 (AC Half Bridge) in Edlog. Recommended excitation voltages
and input ranges are given in TABLE 7-2. TABLE 7-2 shows the excitation
and voltage ranges used with our dataloggers.
TABLE 7-2. Excitation and Voltage Ranges
Datalogger mV Excitation Full Scale Range
CR800/CR850 250 ±250 mV
CR1000 250 ±250 mV
CR3000 200 ±200 mV
CR5000 200 ±200 mV
21X 500 ±500 mV
CR7 500 ±500 mV
CR10(X) 250 ±250 mV
CR23X 200 ±200 mV
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