Omega Products LDM422 User Manual

J-13

⻬ Complete Isolation

with Optical Couplers
and Power DC-to-DC
Converter

⻬ Industrial Surge

Protection Devices

⻬ Six LED Diagnostic

Indicators

⻬ DC to 19,200 Baud at

6000 Feet (1800M), 9600
Baud at 3 Miles (5KM)

⻬ Request-to-Send, Clear-

to-Send Handshake

⻬ Tri-State Outputs for

Multidrop Applications

⻬ Selection of Connectors
⻬ Wide Operation

Temperature Range

⻬ Solderless Screw

Terminal Field
Connections

LDM422 Series

Fully Isolated Limited Distance Modem,
RS-232/422 Converter

The LDM422 is a com pact RS-232
to RS-422 con verter which fea tures
a complete elec tri cal isolation
barrier and heavy duty electrical
surge protectors. These de vices
feature a rug ged aluminum
en clo sure small enough to mount on
the back panel of typical com puter
equipment, sav ing valuable desk
and floor space.

Specifications

Model LDM422

Baud Rate Range 0 – 19.2K
Baud Rate 19.2K 9.6K 4.8K 2.4K 1.2K – 0

Distance (miles) 1.14 3 4 5 7
Distance (km) 1.8 5 6.7 8.3 11.7

Maximum Multidrop 32. Reduced distances may be required when as

many as 32 units are multidropped. No restrictions
apply for distances of 1 mile (1.7 km) or less.

Common Mode Surge: 750V
Isolation Continuous: 500V

Differential Mode (AC input)
Surge Protection ANSI/IEEE C37.90.1-1989
(9 devices) (all RS-422 inputs and outputs)

Channel Lines

(1)

TD, RD, RTS, CTS

Control Lines

(1)

RTS, CTS, DTR, DSR, RLSD

Modes Asynchronous 4-wire duplex, 2-wire half-duplex,

2-wire simplex

Isolation is provided by optical
couplers and a DC-to-DC converter.
The RS-232 con nec tion is through
male or fe male EIA 25-pin con nec ­tors. The RS422 con nec tions are
made through con ve nient solderless
screw terminals.

The LDM422 series is designed for
full du plex op era tion over two-wire
pairs. Out puts are tri-state, al low ing
multidropping of up to 32 units.

Hard ware hand shake is avail able
over two separate wire pairs. Data
rates are 75 to 19,200 baud.
Six di ag nos tic LED indicators are
provided for in stal la tion guidance
and system trou bleshoot ing. The
RS-232 interface sup ports Request
To Send, Clear To Send, Data Set
Ready, Received Line Signal

Detect, and Data Ter mi nal Ready.
A convenient null modem switch is

Notes: (1) TD = Transmit Data, RD = Receive Data, RTS = Request To Send, CTS = Clear
To Send. DTR = Data Terminal Ready, DSR = Data Set Ready, RLSD = Received Line
Signal Detect.

$

246

Basic Unit

Extended Warranty

Program

SM

SERIAL I/O

J-14

J

789101112

A

TD

RD

B

RTN

A'
B'

RTN

Field Connector

1.28 (32.5)

0.13 ±0.01 (3.3 ±0.25)

RS-232 Connector

Connector C/L

0.51 ±0.01

(13.0 ±0.25)

0

0

0

0.26 (6.6)

0.21 ±0.01 (5.3 ±0.25)

0.120 (3.1) Dia (1 Place)

0.315
(8.0)

0.531
(13.5)

Connector

Flange Detail

12VAC

1.65 (41.9)

0.175 ±0.010
(4.4 ±0.25)

2.10 (53.3)

1.852 (47.0)

RTS

CTS

PWR RTN

A

B
A'
B'

1.01 (25.7)

5.25 (133.3)

5.28 (141.7)

Dimensions: Inches (mm)

C/L = Center Line

6.42 (163.1)

123456

Notes: (2) 120VAC and 220VAC power transformers are available. (3) Ground-benign
environmental conditions (no salt atmosphere, <50°C ambient temperature).

Model LDM422

Null Modem Switch 1 (Reverses RS-232 pins 2 and 3)
RS-422 Output Drive 20mA min/output
RS-422 Input Impedance 6kΩ min/input
Power:

AC operation

(2)

12VAC, ±10%, 10W screw terms 1 & 2

DC operation +11.5VDC to +17.0VDC @ 400mA on pin 9

-11.5VDC to -17.0VDC @ 400mA on pin 10

Operating Environment 0°C to 70°C 0 to 95% relative humidity, noncondensing

Dimensions 6.6" x 2.1" x 1.28" (167.6 x 53.3 x 32.5 mm)

Weight 7 oz (200 g) max
AC Transformer 11.0 oz (311.8 g) max

MTBF

(3)

>100,000 hrs

To Order

(Specify Model Number)

Model No. Price RS232 Connector Power Source

LDM422-P $267 25 Pin male Host-powered

LDM422-S 246 25 Pin female Host-powered
LDM422-PT 267 25 Pin male Transformer
LDM422-ST 267 25 Pin female Transformer

Includes operator’s manual. Transformer powered units also include 120 Vac wall mount
transformer. OMEGACARESMextended warranty is available for models shown on this page.
Ask your sales representative for full details when placing order.

Ordering Example: LDM422-ST converter, OMEGACARESM1year warranty for LDM422-ST
(adds 1 year to standard 1 year warranty), $267 + 26 = $293.

pro vid ed for the data lines. The
RS-422 interface sup ports Request
To Send and Clear To 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
data channels.

Data rates are the same. The units
use 12VAC from a wall-mounted
transformer or ±12VDC to pins 9 (+)
and 10 (–) of the RS-232 connector.
The LDM422 conforms to EIA RS­232 and RS-422 speci fi ca tions.
Data Terminal Ready must be
asserted by the host RS-232 port
before the LDM422 can transmit
data. When Data Terminal Ready
is not asserted all outputs of the
LDM422 are high impedance,
allowing up to 32 LDM422 units
to be multidropped on a common
com mu ni ca tions cable. See Figure
on page 2 for details.

Request To Send and Clear To
Send are carried through the
RS-422 port as two separate wire
pairs. These may be used for full
duplex flow control.

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