Dataloggers, which may also be referred to as Measurement and Control Units (Systems) or Microloggers, are the heart of a data acquisition system. They measure sensors at a specific scan rate, process data, store the data, and initiate telecommunication. Our dataloggers also have control capabilities allowing them to respond to specific site conditions by opening flood gates, turning fans off/on, etc.
Most third-party modems require a null modem cable, SC105, SC110 cable, or SC932A to interface with a datalogger. Many modems manufactured by Campbell Scientific can connect directly to a datalogger’s CS I/O port using an SC12 or serial cable.
The number of sensors that can be measured is determined by the sensor(s) and the datalogger(s). See the operator's manual for the sensor to determine the channels each sensor uses. The number of analog channels, pulse counting channels, switched excitation channels, digital ports, and continuous analog ports provided by each datalogger can be found in the small datalogger comparison chart and the large datalogger comparison chart.
The official definition of SDI-12 is Serial Data Interface at 1200 baud. Having stated that, SDI-12 is a protocol that was developed within the water resources field to make it easier to determine if a sensor and a datalogger were compatible. Instead of having to work through the specifications of the datalogger and the sensor for output, input, excitation, wiring, power, programming, etc., all SDI-12 sensors would have just three wires—a serial data line, a ground line, and a 12 V power line.
Review the tutorial “Updating a Datalogger Operating System.”
Communication through the datalogger’s CS I/O port requires an interface that converts the computer’s RS-232 voltage levels to the CMOS levels of the datalogger. Typically, that interface is an SC32B. The SC32B connects to the datalogger’s CS I/O port via an SC12 or serial cable and connects to a computer’s 9-pin serial port via a serial cable. When the computer does not have a serial port, a 9-pin serial-to-USB cable, such as pn 17394, can be used with the SC32B. Alternatively, instead of the SC32B, use the SC-USB.
The CR510, CR500, CR10X, CR23X, CR800, CR850, CR3000, and CR1000 can be used for Modbus applications.
The CR510, CR500, and CR10X require a special operating system. Purchase an operating system with the Modbus protocol, and download it to the datalogger using CSOS downloading software or the DevConfig Utility.
Modbus protocol is standard in the CR23X, CR800, CR850, CR3000, and CR1000.
Yes. The datalogger can control power to external devices under program control. For more information, see the “Decisions, Decisions, Decisions…” article.
To turn a generator on and off, a solid state relay with a load capacity that matches or exceeds the power of the generator is needed. The relay is controlled by one of the control ports on the datalogger.
The CR1000, CR800, CR850, and CR3000 can accept PakBus connections from multiple terminals simultaneously, provided that all of the connecting nodes have unique PakBus addresses.
Campbell Scientific dataloggers do not directly support BACnet, but an industrial protocol converter can be used to add a datalogger to a new or existing BACnet network. The protocol converter sits between the datalogger and the network, and it converts BACnet requests to a protocol supported by the datalogger, such as Modbus, DNP3, SNMP, or others.
For more information about BACnet, see the “BACnet to Modbus/Modbus to BACnet Protocol Conversion” application note.
Campbell Scientific dataloggers do not directly support Profibus, but an industrial protocol converter can be used to add a datalogger to a new or existing Profibus network. The protocol converter sits between the datalogger and the network, and it converts Profibus requests to a protocol supported by the datalogger, such as Modbus, DNP3, SNMP, or others.
Campbell Scientific dataloggers do not directly support LonWorks, but an industrial protocol converter can be used to add a datalogger to a new or existing LonWorks network. The protocol converter sits between the datalogger and the network, and it converts LonWorks requests to a protocol supported by the datalogger, such as Modbus, DNP3, SNMP, or others.
Yes. All Campbell Scientific dataloggers currently have nonvolatile memory. Nonvolatile memory was added to the CR10X in 1996. All datalogger models introduced since then have included nonvolatile memory.
Nonvolatile memory is reliant on the 3 V lithium battery inside the datalogger. As long as this internal battery has a charge above 3 V, no data should be lost if the datalogger loses power.
Yes. Campbell Scientific offers a variety of telecommunications options, including Wi-Fi, spread-spectrum radio modems, licensed radio-frequency modems, cellular modems, satellite transmitters (send data only), wired Ethernet, land-line phone modems, and other direct connection methods.
Yes. A datalogger can address up to 15 SDM addresses (0 through 14). (SDM address 15 is reserved for the SDM Group Trigger Command.) Remember that SDM is a serial communications protocol; as more devices are added to the SDM bus, it takes more program execution time to transmit the data.
Yes, but there is the potential for explosive hydrogen gas from a rechargeable battery to build up inside the airtight, waterproof enclosure. Care should be exercised in choosing a power supply for applications where the enclosure must be waterproof. Contact Campbell Scientific’s technical support for more information.
Possibly. If a voltage greater than 16 Vdc is applied to the wiring panel, it could damage the input and result in inaccurate measurements.
Additionally, in some cases the sensors can be damaged if they are wired to the wrong channels. If a sensor, wired into an analog input channel, has an output of more than 5 Vdc, measurements on adjacent analog input channels may be upset. For example, the maximum full-scale range on the CR5000 is ± 5Vdc.
Yes. We have developed programs for controlling devices and collecting data remotely. Program examples and datalogger wiring are provided in the 10164-L instruction manual. Contact an application engineer at Campbell Scientific for more information.
The memory in the data cache is considered ring memory. This means that after the data cache fills up, new records begin overwriting the oldest records.
Resources and Links
About Dataloggers and Data Acquisition Systems
Campbell Scientific dataloggers are at the center of our rugged, reliable data acquisition systems. Our dataloggers share similar measurement and programming capabilities; selection of the appropriate datalogger depends mainly on the type, number, precision, and speed of measurements required.
Multiplexers and SDM devices may be added to augment measurement and control capabilities that include:
- - Measuring most sensors
- - Providing nonvolatile data storage and on-board battery-backed clock (excludes CR7)
- - On-board data processing
- - Initiating measurement and control functions based on time or event
- - Controlling external devices such as pumps, motors, alarms, freezers, valves, etc.
- - Using our PC support software or keyboard/display to program
- - Operating independently of ac power, computers, and human interaction
- - Consuming minimal power from a 12 Vdc source
- - Interfacing with on-site and telecommunication devices such as telephone modems (including cellular and voice-synthesized), short haul modems, radio transceivers, satellite transmitters, and ethernet interfaces
- - Operating temperature range of -25° to 50ºC (Optional extended ranges are available.)
Note: many companies use the term "data logger" instead of "datalogger". For us, the terms are synonomous. Since dataloggers make up our core product offering, we say and write the term hundreds of times daily, and it's just natural for us to put "data" and "logger" together to form a single word.