General serial communications

The data logger supports two-way serial communications. These communications ports can be used with smart sensors that deliver measurement data through serial-data protocols, or with devices such as modems, that communicate using serial data protocols.

ClosedCRBasic Campbell Scientific's BASIC-like programming language that supports analog and digital measurements, data processing and analysis routines, hardware control, and many communications protocols. instructions for general serial communications include:

  • SerialOpen()
  • SerialClose()
  • SerialIn()
  • SerialInRecord()
  • SerialInBlock()
  • SerialInChk()
  • SerialOut()
  • SerialOutBlock()
  • SerialBrk()
  • SerialFlush()

See the CRBasic Editor help for detailed instruction information and program examples: https://help.campbellsci.com/crbasic/cr300/ .

To communicate over a serial port, it is important to be familiar with the protocol used by the device with which you will be communicating. Refer to the manual of the sensor or device to find its protocol and then select the appropriate options for each CRBasic parameter. See the application note Interfacing Serial Sensors with Campbell Scientific Dataloggers for more programming details and examples.

NOTE:

Though COM1 (C1/C2) uses RS-232 logic levels, it is limited to 0 V (logic high) and 5 V (logic low) output. This may make COM1 incompatible with some serial devices.

COM1 is not capable of TTL logic levels and so is not compatible with TTL-to-RS-232 converters for the purpose of presenting a true RS-232 interface.

COM1 also has a low input resistance that may make it incompatible with some serial devices with the addition of in-line resistance.