Communications ports

The data logger is equipped with ports that allow communications with other devices and networks, such as:

Campbell Scientific data logger communications ports include:

USB device port

The USB device port supports communicating with a computer through Closeddata 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. or through virtual Ethernet (ClosedRNDIS Remote Network Driver Interface Specification - a Microsoft protocol that provides a virtual Ethernet link via USB.), and provides 5 VDC power to the data logger (powering through the USB port has limitations - details are available in the specifications). The data logger USB device port does not support USB flash or thumb drives. Although the USB connection supplies 5 V power, a 12 VDC battery will be needed for field deployment.

Ethernet port

The RJ45 10/100 Ethernet port is used for IP communications.

C and U terminals for communications

C and U terminals are configurable for the following communications types:

  • SDI-12
  • RS-232
  • RS-422
  • RS-485
  • TTL (0 to 5 V)
  • LVTTL (0 to 3.3 V)
  • SDM

Some communications types require more than one terminal, and some are only available on specific terminals. See Communications specifications for more information.

SDI-12 ports

ClosedSDI-12 Serial Data Interface at 1200 baud. Communications protocol for transferring data between the data logger and SDI-12 compatible smart sensors. is a 1200 baud protocol that supports many smart sensors. C1, C3, U1, U3, U5, U7, U9, and U11 can each be configured as SDI-12 ports. Maximum cable lengths depend on the number of sensors connected, the type of cable used, and the environment of the application. Refer to the sensor manual for guidance.

For more information, see SDI-12 communications.

RS-232, RS-422, RS-485, TTL, and LVTTL ports

RS-232, RS-422, RS-485, TTL, and LVTTL communications are typically used for the following:

  • Reading sensors with serial output
  • Creating a multi-drop network
  • Communications with other data loggers or devices over long cables

Configure C or U terminals as serial ports using ClosedDevice Configuration Utility Software tool used to set up data loggers and peripherals, and to configure PakBus settings before those devices are deployed in the field and/or added to networks. Also called DevConfig. or by using the SerialOpen() CRBasic instruction. C and U terminals are configured in pairs for TTL and LVTTL communications, and C terminals are configured in pairs for RS-232 or half-duplex RS-422 and RS-485. All four C terminals are required for full-duplex RS-422. See also Communications protocols.

NOTE:

RS-232 ports are not isolated.

SDM ports

SDM is a protocol proprietary to Campbell Scientific that supports several Campbell Scientific digital sensor and communications input and output expansion peripherals and select smart sensors. It uses a common bus and addresses each node. CRBasic SDM device and sensor instructions configure terminals C1, C2, and C3 together to create an SDM port. Alternatively, terminals U1, U2, and U3; U5, U6, and U7; or U9, U10, and U11 can be configured together to be used as SDM ports by using the SDMBeginPort() instruction.

See also Communications specifications.

CS I/O port

One nine-pin port, labeled CS I/O, is available for communicating with a computer through Campbell Scientific communications interfaces, modems, and peripherals. Campbell Scientific recommends keeping CS I/O cables short (maximum of a few feet). See also Communications specifications.

CS I/O pinout
Pin
number		 Function Input (I)
Output (O)		 Description
1 5 VDC O 5 VDC: sources 5 VDC, used to power peripherals.
2 SG   Signal ground: provides a power return for pin 1 (5V), and is used as a reference for voltage levels.
3 RING I Ring: raised by a peripheral to put the CR6 in the telecom mode.
4 RXD I Receive data: serial data transmitted by a peripheral are received on pin 4.
5 ME O Modem enable: raised when the CR6 determines that a modem raised the ring line.
6 SDE O Synchronous device enable: addresses synchronous devices (SD); used as an enable line for printers.
7 CLK/HS I/O Clock/handshake: with the SDE and TXD lines addresses and transfers data to SDs. When not used as a clock, pin 7 can be used as a handshake line; during printer output, high enables, low disables.
8 12 VDC   Nominal 12 VDC power. Same power as 12V and SW12 terminals.
9 TXD O Transmit data: transmits serial data from the data logger to peripherals on pin 9; logic-low marking (0V), logic-high spacing (5V), standard-asynchronous ASCII: eight data bits, no parity, one start bit, one stop bit. User selectable baud rates: 300, 1200, 2400, 4800, 9600, 19200, 38400, 115200.

RS-232/CPI port

The data logger includes one RJ45 module jack labeled ClosedRS-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./CPI. ClosedCPI CPI is a proprietary interface for communications between Campbell Scientific data loggers and Campbell Scientific CDM peripheral devices. It consists of a physical layer definition and a data protocol. is a proprietary interface for communications between Campbell Scientific data loggers and Campbell Scientific CDM peripheral devices and smart sensors. It consists of a physical layer definition and a data protocol. CDM devices are similar to Campbell Scientific ClosedSDM Synchronous Device for Measurement. A processor-based peripheral device or sensor that communicates with the data logger via hardwire over a short distance using a protocol proprietary to Campbell Scientific. devices in concept, but the CPI bus enables higher data-throughput rates and use of longer cables. CDM devices require more power to operate in general than do SDM devices. CPI ports also enable networking between compatible Campbell Scientific data loggers. Consult the manuals for CDM modules for more information.

NOTE:

RS-232/CPI port is not isolated.

CPI port power levels are controlled automatically by the CR6:

  • Off: Not used.
  • High power: Fully active.
  • Low-power standby: Used whenever possible.
  • Low-power bus: Sets bus and modules to low power.

When used with a Campbell Scientific RJ45-to-DB9 converter cable, the RS-232/CPI port can be used as an RS-232 port. It defaults to 115200 bps (in autobaud mode), 8 data bits, no parity, and 1 stop bit. Use Device Configuration Utility or the SerialOpen() CRBasic instruction to change these options.

RS-232/CPI pinout
Pin number Description
1 RS-232: Transmit (Tx)
2 RS-232: Receive (Rx)
3 100 Ω Res Ground
4 CPI: Data
5 CPI: Data
6 100 Ω Res Ground
7 RS-232 CTS CPI: Sync
8 RS-232 DTR CPI: Sync
9 Not Used