Analog Voltage Input Signal Conditioners, Narrow Bandwidth LDM422
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Industrial Data Communication Products > Description The LDM422 is a compact RS-232 to RS-422 converter which features acomplete electrical isolation barrier and heavy duty electrical surge protectors.These devices feature a rugged aluminum enclosure small enough to mount onthe back panel of typical computer equipment, saving valuable desk and floor space. Isolation is provided by optical couplers and a DC-to-DC converter.The RS-232 connection is through male or female EIA 25-pin connectors. TheRS422 connections are made through convenient solderless screw terminals.The LDM422 series is designed for full duplex operation over two-wire pairs.Outputs are tri-state, allowing multidropping of up to 32 units. Hardwarehandshake is available over two separate wire pairs. Data rates are 75 to 19,200 bits per second. Six diagnostic LED indicators are provided (see Figure 1) forinstallation guidance and system troubleshooting. The RS-232 interface sup-ports Request To Send, Clear To Send, Data Set Ready, Received Line Signal Detect, and Data Terminal Ready. A convenient null modem switch is providedfor the data lines. The RS-422 interface supports Request To Send and ClearTo Send on separate wire pairs. The LDM422 may be used to convert two sets of send and receive channels by using RTS and CTS circuits as the second datachannels. Data rates are the same. The units use 12VAC from a wall-mountedtransformer or 12VDC to pins 9 (+) and 10 (і) of the RS-232 connector. Features ?Complete Isolation with Optical Couplers andPower DC-to-DC Converter?Industrial Surge Protection Devices?Six LED Diagnostic Indicators?DC to 19,200bps at 6000 Feet (1800m),9600bps at 3 Miles (5km)?Request-To-Send, Clear-To-Send Handshake?Tri-state Outputs for Multidrop Applications?Selection of Connectors?Wide Operating Temperature Range ?Solderless Screw Terminal Field Connections?CE Compliant Figure 1: LDM422 Block Diagram

Bit Rate (bps)0-19.2kbps vs Distance19.2k9.6k4.8k2.4k1.2k-0Distance(miles) 1.143.04.05.07.0 Distance(km) 1.84.86.48.111.3Maximum Multidrop Units32. Reduced distances may be required when asmany as 32 units are multidropped. Norestrictions apply for distances of 1 mile (1.7 km) or less.Common Mode IsolationSurge: 750VContinuous: 500VDifferential Mode Surge Protection(AC input) (9 devices)ANSI/IEEE C37.90.1(all RS-422 inputs and outputs)ModesAsynchronous 4-wire duplex, 2-wire half-duplex,2-wire simplexChannel Lines > Pin 1CASEGroundPin 112VACPin 2TD[3]Transmit DataPin 2PWR RTN Pin...