The MD485 is an intelligent RS-485 interface that permits a PC to address and communicate with one or more data loggers over a distance of up to 1200 m. This interface also supports data-logger-to-data-logger communication, callback from a remote data logger, PC-to-printer communications, and digital camera-to-data-logger connections.Read More
The MD485 includes three ports (RS-232, CS I/O, RS-485) for connecting a PC, a data logger, or another MD485. Any two ports can be used at a time.
The MD485 can be configured to provide transparent communications, MD9 emulation, and PakBus networking. Although the MD485 can emulate an MD9, the MD485 can not be added to an existing MD9 network. PakBus networking requires the data loggers to use the PakBus communications protocol. PC400 or LoggerNet software is used to initiate and control the communications link.
The MD485 is shipped with the 10873 cable and SC12 cable for connecting it to a PC or data logger. Point-to-point and point-to-multipoint networks use the following equipment:
AC power is typically used at the computer site; a pn 15966 wall charger is required. At the field site, the MD485 is powered by the data logger through its CS I/O port. If the MD485 is connected to the data logger’s RS-232 port instead of the CS I/O port, or if the data logger was purchased before 12/97, a pn 14291 Field Power Cable is required. Phone-to-MD485 and spread spectrum radio-to-MD485 networks also require a power supply with a null modem port . An A100 adapter used with a PS150 or PS200 power supply provides this capability. The PS150 or PS200 is recharged via a wall charger or a solar panel.
|Baud Rates||1200, 9600, 19.2k, 38.4k, 57.6k, 115.2k bps|
|Voltage||12 Vdc (from data logger or pn 15966 wall charger)|
|Surge||Complies with IEC61000-4-5, test level 3 (±2 kV, 2 Ω coupling impedance)|
|Maximum Cable Length||1,219 m (4,000 ft)|
|Dimensions||15.88 x 6.35 x 1.91 cm (6.25 x 2.5 x 0.75 in.)|
|Weight||127.6 g (4.5 oz)|
|Standby Mode||1.2 mA|
|Communicating||2 to 7 mA|
|Standby Mode||14.4 mW|
|Communicating||24 to 84 mW|
|Air Discharge||Complies with IEC61000-4-2, test level 4 (±15 kV)|
|Contact Discharge||Complies with IEC61000-4-2, test level 4 (±8 kV)|
Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.
|CR300||Use a 18663 null modem cable.|
|CR6||The CR6 has integrated RS-485.|
A desiccated, non-condensing environment is required. The MD485 includes built-in keyhole flanges for mounting to the backplate of a Campbell Scientific enclosure.
The MD485 can be combined with our AVW200-series Vibrating-Wire Interfaces, CC640 Digital Camera, Ethernet links, phone modems (including cellular), and spread spectrum radios. Field site equipment should be housed in an environmental enclosure. Information about configuring the other devices is provided in the user manuals.
AC power is typically used at the computer site; a pn 15966 wall charger is required. At the field site, the MD485 is powered by the data logger through its CS I/O port. If the MD485 is connected to the data logger’s RS-232 port instead of the CS I/O port, or if the data logger was purchased before 12/97, a pn 14291 Field Power Cable is required. Phone-to-MD485 and spread spectrum radio-to-MD485 networks also require a power supply with a null modem port. An A100 adapter used with a PS150 or PS200 power supply provides this capability. The PS150 or PS200 is recharged via a wall charger or a solar panel.
Current MD485 operating system. Requires the Device Configuration Utility.
A software utility used to download operating systems and set up Campbell Scientific hardware. Also will update PakBus Graph and the Network Planner if they have been installed previously by another Campbell Scientific software package.
Supported Operating Systems:
Windows 10, 8.1, 8, and 7 (Both 32 and 64 bit)
Number of FAQs related to MD485: 13
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No. Isolation circuitry is not always needed, and it presents a significant increase in power consumption for battery-operated stations. For situations where external isolation modules are required, external isolation modules can be added between stations.
No. The MD485 is configured to be a serial converter between two of the interfaces. The MD485 serves to convert CS I/O to RS-485, RS-232 to RS-485, or CS I/O to RS-232.
No. The RS-485 data transceivers used in the MD485 feature fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted. Because of this, biasing resistors are not needed. The transceivers also feature reduced slew-rate drivers that minimize electromagnetic interference (EMI) and reduce reflections. Because of this, termination resistors do not need to be used for most applications.
RS-485 networks should follow a bus topology whenever possible (devices daisy-chained in a linear fashion). The total amount of cable used in a single network should not exceed 1,200 m. An RS-485 repeater or a data logger with multiple MD485 devices can be used to extend the length of a network or to create more complex network topologies.
256 MD485 devices can exist on a single bus. The MD485 presents ⅛ of a unit load (electrical impedance load) to the network. An RS-485 network should not exceed 32 unit loads: 256 ∙ ⅛ = 32.
Absolutely. The RS-485 interface of the MD485 meets the EIA/TIA-485 standards for half-duplex communications. Campbell Scientific customers have used the MD485 in conjunction with many other off-the-shelf RS-485 interfaces.
Typically, only one MD485 is connected to a data logger. Sometimes two are connected to create different network segments. Technically, however, one MD485 can be connected to each data logger serial port, and up to five MD485 devices can be connected to a single data logger CS I/O port.
No. The device can also be connected directly to other devices such as a computer, radio, cellular modem, serial server, or other vendor RTU. When it is not connected to a data logger, the MD485 is most commonly used to create a multidrop network behind another communications peripheral or off a computer’s serial port.
Transparent Communications should be used for all non-PakBus communications. It passes data from one interface to another without regard to the underlying protocol.
PakBus Networking implements a collision avoidance technique based on knowledge of the PakBus protocol. This mode should be used for PakBus communications.
The MD485 is compatible with nearly any serial line communications protocol. Most notably, the MD485 is regularly used for PakBus, Modbus RTU, Modbus ASCII, and DNP3.