RS-232 Port

RS-232 Recommended Standard 232. A loose standard defining how two computing devices can communicate with each other. The implementation of RS-232 in Campbell Scientific data loggers to computer communications is quite rigid, but transparent to most users. Features in the data logger that implement RS-232 communications with smart sensors are flexible. represents a loose standard defining how two computing devices can communicate with each other. For instruction on setting up RS-232 communications with a computer, see USB or RS-232 communications.

One nine-pin DCE Data Communications Equipment. While the term has much wider meaning, in the limited context of practical use with the data logger, it denotes the pin configuration, gender, and function of an RS-232 port. The RS-232 port on the data logger is DCE. Interfacing a DCE device to a DCE device requires a null-modem cable. port, labeled RS-232, normally is used to communicate with a computer running data logger support software LoggerNet, RTDAQ, and PC400 - these Campbell Scientific software applications include at least the following functions: data logger communications, downloading programs, clock setting, and retrieval of measurement data., to connect a modem, or to read a smart sensor. The RS‑232 port functions as either a DCE Data Communications Equipment. While the term has much wider meaning, in the limited context of practical use with the data logger, it denotes the pin configuration, gender, and function of an RS-232 port. The RS-232 port on the data logger is DCE. Interfacing a DCE device to a DCE device requires a null-modem cable. or DTE Data Terminal Equipment. While the term has much wider meaning, in the limited context of practical use with the data logger, it denotes the pin configuration, gender, and function of an RS-232 port. The RS-232 port on the data logger is DCE. Attachment of a null-modem cable to a DCE device effectively converts it to a DTE device. device. The most common use of the RS-232 port is as a connection to a computer DTE device (using a standard DB9-to-DB9 cable). Pins 1, 4, 6, and 9 function differently than a standard DCE device to accommodate a connection to a modem or other DCE device via a null modem cable. For the RS-232 port to function as a DTE device, a null modem adapter is required.

RS-232 communications normally operate well up to a transmission cable capacitance of 2500 picofarads, or approximately 50 feet of commonly available serial cable.

RS-232 Power States

Under normal operation, the RS-232 port is powered down waiting for input. Upon receiving input, there is a 40-second software timeout before shutting down. The 40-second timeout is generally circumvented when communicating with data logger support software LoggerNet, RTDAQ, and PC400 - these Campbell Scientific software applications include at least the following functions: data logger communications, downloading programs, clock setting, and retrieval of measurement data. because it sends information as part of the protocol that lets the data logger know it can shut down the port.

When in sleep mode, hardware is configured to detect activity and wake up. Sleep mode may lose the first character of the incoming data stream. PakBus ® A proprietary communications protocol developed by Campbell Scientific to facilitate communications between Campbell Scientific devices. Similar in concept to IP (Internet Protocol), PakBus is a packet-switched network protocol with routing capabilities. A registered trademark of Campbell Scientific, Inc. takes this into consideration in the "ring packets" that are preceded with extra sync bytes at the start of the packet. SerialOpen() leaves the interface powered-up, so no incoming bytes are lost. See the CRBasic Editor help for detailed instruction information and program examples: https://help.campbellsci.com/crbasic/cr350/ .

When the data logger has data to send via RS-232, if the data is not a response to a received packet, such as sending a beacon, it will power up the interface, send the data, and return to sleep mode without a 40 second timeout.