l
Using low capacitance, low resistance, screened cable
l
Ensuring that the power ground cable has low resistance and is connected to the same
ground reference as the data logger control or U terminals
8.3 Power conservation
The CS225 draws less than 1 mA of current per sensor between polling sessions from its 12 V
supply. In many applications, this is minimal compared to overall system power use, so the sensor
can be permanently powered to avoid the warm-up period.
In low power applications, you can switch the power on a minimum of 10 s (allowing for the
warm-up period) before polling the CS225. This switching can be achieved in different ways
depending on the type and model of your data logger. If available, the switched 12 V output of
the data logger can be used.
8. Maintenance, calibration, and
troubleshooting
The CS225 probe requires no maintenance nor calibration. The following are symptoms and
possible corrections.
Symptom: –9999 or NAN for temperature
1. Verify the green wire is connected to the control terminal specified by the SDI-12
measurement instruction.
2. Verify the red power wire is connected to a 12V terminal; check the voltage with a digital
volt meter. If a switched 12V terminal is used, temporarily connect the red wire to a 12V
terminal (non-switched) for test purposes.
Symptom: Sensor won’t respond to command
1. Expected address not used or has been changed.
a. Confirm all addresses in use with the
aI!
command to determine the individual
addresses of each temperature sensor.
CS225 Temperature String
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