CS547A-L Water Conductivity and Temperature Probe
Corrosion Resistant
Epoxy housing is durable and easy to clean
weather applications supported water applications supported energy applications supported gas flux and turbulence applications supported infrastructure applications supported soil applications supported


The CS547A probe monitors the electrical conductivity (EC) and temperature of water. EC is measured with three cylindrical stainless-steel electrodes mounted in an epoxy housing. The electrode configuration eliminates ground loop problems associated with sensors in electrical contact with earth ground. The electrodes are ac coupled, and a bipolar excitation is applied. This reduces electrochemical reactions, minimizes corrosion, and extends the probe’s life. Temperature is sensed with a thermistor.

The CS547A is shipped with a cell constant calibrated in a 0.01 molal KCl solution at 25°C. The solution has an EC of 1.408 mS cm-1.

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Benefits and Features

  • Compatible with most Campbell Scientific data loggers
  • Easy to clean
  • Corrosion resistant
  • Rounded ends facilitate installation and removal
  • Compatible with AM16/32-series multiplexers allowing measurement of multiple sensors
  • Weighted option available for stand-alone submersion



Conductivity Measurement Range ~0.005 to 7 mS/cm
Temperature Measurement Range 0° to 50°C
Conductivity Accuracy
  • The EC accuracy is in a KCl and Na2SO4, NaHCO3, and NaCl Standard Solutions @ 25°C.
  • ±5% of reading (for 0.44 to 7.0 mS cm-1 range)
Temperature Polynomial Linearization Error Typically < 0.1°C (over 0° to 48°C)
Thermistor Interchangeability Typically < 0.2°C (over 0° to 50°C)
Wetted Materials Epoxy housing, 316 stainless-steel rings, polyurethane cable
pH Operating Range Solution pH of less than 3.0 or greater than 9.0 may damage the stainless-steel housing.
Operating Temperature Range 0° to 50°C
Depth Rating 305 m (1000 ft) maximum
Dimensions 8.9 x 2.54 x 1.9 cm (3.5 x 1 x 0.75 in)
  • 45 g (2 oz)
  • 120 g (4.2 oz) with 1.22 m (4 ft) cable
Weighted Cable Weight 80 g (2.8 oz)


Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.

Data Loggers

Compatible Note
21X (retired)
CR10 (retired)
CR1000 (retired)
CR10X (retired)
CR200X (retired)
CR206X (retired)
CR23X (retired)
CR295X (retired)
CR500 (retired) The CR500 cannot measure more than one CS547A probe because it does not provide enough excitation channels to measure more probes.
CR5000 (retired)
CR510 (retired) The CR510 cannot measure more than one CS547A probe because it does not provide enough excitation channels to measure more probes.
CR9000 (retired)
CR9000X (retired)

Additional Compatibility Information

The minimum pipe ID that the CS547A-L fits is 2.79 cm (1.1 in.).

Data Logger Considerations

The A547 Interface is required for connecting the probe to the data logger. This interface contains the blocking capacitors and bridge completion resistors necessary for the conductivity measurement.

A 3-ft cable is shipped with the sensor to connect the A547 to the data logger terminals. The CS547A requires one differential analog input, one single-ended analog input, and two excitation channels. One excitation channel must be capable of delivering ac excitation, so the BDR301 or BDR320 are NOT compatible.

Using Multiple CS547A Conductivity Probes

Special considerations apply when two or more CS547A probes will be measured by a single data logger.

A CR510 cannot be used to measure two probes because it does not provide sufficient (three) excitation channels.

Although it is acceptable for the two thermistors to share an excitation channel, each conductivity measurement requires a dedicated excitation channel. If excitation for the conductivity measurement were to be shared from a common excitation channel, both solutions would become polarized and once excitation was removed, some charge could be transferred from one solution to the other making the measurements interdependent on one another. If more than two CS547A probes are to be measured, then an AM16/32-series multiplexer is required.


If more than two CS547A probes are to be measured, then an AM16/32-series multiplexer is required. In this scenario, each probe is wired to the multiplexer and one A547 interface is wired between the multiplexer and the data logger. If the system were maximized, up to sixteen CS547As could be connected to the multiplexer. However, because the A547 becomes a part of the measurement circuit for all connections to the multiplexer, only CS547A probes could be connected to the multiplexer (i.e., it is not possible to mix other sensor types with the CS547As attached to the multiplexer).

FAQs for

Number of FAQs related to CS547A-L: 18

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  1. Yes. Each CS547A-L is shipped with pn 77854-inch Nylon brush.

  2. The readings will be accurate for the sample of water inside the cavity, but that may or may not be indicative of the overall conductivity of the well. Flowing water allows a more representative measurement over time.

  3. One A547 interface is needed for each CS547A-L, unless a multiplexer is used. A multiplexer is capable of switching up to 16 CS547A-L sensors through one A547 interface.

  4. Position the CS547A-L so that it is protected during high flow but remains submerged at base flow.  Orient the measurement cavity parallel to the water flow.

  5. Exciting the CS547A-L with an electrical charge to make a measurement causes ionization. The ionization correction code corrects for this disruption.

  6. Two CS547A-L sensors can be wired directly to one CR1000. One A547 interface is needed for each sensor, unless a multiplexer is used. A multiplexer switches all sensors through one A547 interface. 

    The CS547A instruction manual offers this warning: "Wire the conductivity excitation and temperature excitation lines in different excitation ports or measurement errors will occur. If multiple CS547A/A547s are wired to one data logger, each conductivity excitation must use a separate excitation port. However, you can wire multiple temperature excitation lines into the same excitation port."

  7. The CS547A-L has a built-in thermistor that is used for this purpose.

  8. The units of conductivity are mS/cm or millisiemens per cm.

  9. If the measurement cavity is kept clean, ephemeral conditions should not affect the reading.

  10. An analog voltage signal of no more than 2500 mVdc.