Campbell Scientific MD485 RS-485 Multidrop Interface - Manual (Page 7)

MD485 RS-485 Multidrop Interface
1. Introduction
The MD485 is an intelligent RS-485 interface. It is configurable to use any
two of its three interface ports (RS-485, RS-232 and CS I/O) at a time.
The MD485 device's primary function is to provide a connection to an RS-485
network (using CS I/O or RS-232). It can also be used to provide an RS-232
connection to a datalogger's CS I/O port (SDC or ME).
MD485s may be networked thereby permitting a computer to address and
communicate with multiple dataloggers. There are two RS-485 terminals to
allow for easy networking. Both are connected to the same port internally, so
either may be used for an RS-485 connection. For networking, one may be
used for input and the other for output. Total cable length may be up to 4000
feet.
With the communication link initiated and controlled by a PC using Campbell
Scientific's LoggerNet or similar software, the operation of the MD485 in the
system is transparent to the user.
2. Specifications
TABLE 1. Specifications
Size: 6.25 x 2.5 x .75 in. (15.88 x 6.35 x 1.91 cm)
Weight: 4.5 oz. (127.6 g)
Accessories: RS-232 cable, SC12 cable, 3-pin Terminal Block (2)
Voltage: 12 Volts from datalogger or Transformer (#15966)
Current:
Standby
1.2 mA
Communicating 2-7 mA
Power:
Standby
14.4 mW
Communicating 24-84 mW
ESD:
Air Discharge Complies with IEC61000-4-2, test level 4 (±15 kV)
Contact Discharge Complies with IEC61000-4-2, test level 4 (±8 kV)
Surge: Complies with IEC61000-4-5, test level 3 (±2 kV, 2 ohms coupling
impedance)
Temperature range: -25 to +50oC
Baud rates: 115.2K, 57.6K, 38.4K, 19.2K, 9600, 1200
Communication cable: CABLE2TP-L two-twisted-pair cable
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