$
205
Basic Unit
⻬ DC to 57,600 Baud
⻬ Complete Isolation
with Optical Couplers
and Power DC-to-DC
Converter
⻬ Data Terminal Ready,
Carrier Detect
Handshake Without
Extra Wires
⻬ Surge Protectors
⻬ Four LED Diagnostic
Indicators
⻬ Operation to 3 Miles
(5 KM) at 9600 Baud,
1 Mile (1.7 KM) at 19,200,
0.5 Miles (0.8 KM) at
57,600
⻬ Four-Wire Full Duplex,
Two-Wire Simplex
⻬ Self-Powered or
Host-Powered
⻬ Selection of Connectors
⻬ Wide Operating
Temperature Range:
0 to 70°C
The LDM70 Series of products is
designed to allow video display
terminals (VDTs) and other RS-232
devi ces to be connected over
distances sufficient to cover any
industrial or institutional complex of
build ings. These modems feature a
rugged aluminum en clo sure small
enough to mount on the back panel
of VDT units, saving valuable desk
and floor space.
The LDM70 Series is designed for
full duplex, asyn chro nous operation
over two DC-continuity, non-load ed,
twisted-wire pairs. Through special
high-speed op ti cal ly coupled
circuits, they may com mu ni cate at
data rates up to 57,600 baud.
A handshake operation is
implemented over the same
two-wire pairs. A self-powered
model and a host-powered model
are avail able. The self-powered unit
uses 12 Vac from a wall-mounted
trans form er, while the host-powered
unit takes ±DC power from pins
9 and 10 of the RS-232 connector.
The modem circuits—and,
consequently, the host device—are
protected from electrical tran sients
due to lightning strikes or operation
of heavy in dus tri al equipment.
Each de vice features a convenient
Data-Communication Equipment
(DCE) to Data-Terminal Equipment
(DTE) switch which reverses pins
2 and 3 of the RS-232 connector.
J-11
LDM70 Series Fully Isolated Limited Distance Modem
12VAC
AC GND
+
-
+
-
+
-
+
-
6' min.
(1.8)
RD
TD
12VAC
AC GND
RD
TD
Wall Transformer
(included with
PT, ST, PJT,
SJT models)
Up to 12 miles
(20 km)
Dimensions Shown in Inches (mm)
Extended Warranty
Program
SM
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: LDM70-ST converter,
OMEGACARE
SM
1 year warranty for LDM70-ST
(adds 1 year to standard 1 year warranty) $226 + 25 = $251.
Model LDM70
Baud Rate Range 0 – 57.6K
Baud Rate 57.6K 38.4K 19.2K 9.6K 4.8K 2.4K 1.2K – 0
Distance (miles) 0.5 0.75 1.0 3 5 8 12
Distance (km) 0.8 1.25 1.7 5 8.3 13.3 20
Common Mode Isolation 1500V Surge, 1000 Vrms Continuous
Differential Mode
Surge Protection
(3 devices) ANSI/IEEE C37.90.1-1989
Channel Lines
(1)
TD, RD
Control Lines
(1)
DTR, RLSD
Modes Asynchronous 4-wire duplex, 2-wire simplex
Power:
AC operation
(
2)
12VAC at 120mA
DC operation ±9VDC to ±15VDC, 45mA
Operating Environment 0 to 70°C, 0 to 95% relative humidity, noncondensing
Dimensions 5.7 x 2.1 x 1" (144.8 x 53.3 x 25.4 mm)
Weight 156 g (5.5 oz) max
AC Transformer 311.8 g (11.0 oz) max
MTBF
(3)
>100,000 hrs
To Order
(Specify Model Number)
Model RS232 Field Power
Number Price Connector Connector Source
LDM70-P $205 25 Pin male Screw termination Host-powered
LDM70-S 205 25 Pin female Screw termination Host-powered
LDM70-PT 226 25 Pin male Screw termination Transformer
LDM70-ST 226 25 Pin female Screw termination Transformer
J
RD+ 2
RD- 3
TD+ 4
TD- 5
Modular Phone
Jack Option
Field Connector
RS-232 Connector
Connector C/L
1.852 (47.0)
2.1 (53.3)
Screw Terms
1.65 (41.9)
12
VAC
AC
GND
RD+
RDTD+
TD-
1
2
000.315
(8.0)
0.531
(13.5)
0.120 (3.0) Dia
5.35
(135.9)
1.0 (25.4)
0.13 ±0.01 (3.3 ±0.25)
0.25 (6.4)
0.50 ±0.01 C/L
(12.7 ±0.25)
0.175 ±0.01
(4.4 ±0.25)
0.19 ±0.01
(4.8 ±0.25)
Dimensions: Inches (mm)
C/L = Center Line
Connector
Flange Detail
0.72
(18.3)
3
4
5
6
Notes: (1) TD = Transmit Data, RD = Receive Data, DTR = Data Terminal Ready, RLSD =
Received Line Signal Detect. (2) 120 Vac and 220 Vac power transformers are available. (3)
Ground-benign environmental conditions (no salt atmosphere, <50°C ambient temperature).
Specifications
For installation and trouble shooting,
each unit has di ag nos tic
Light-Emitting Diodes (LEDs) on the
transmit and receive lines. In
addition, LEDs indicate valid carrier
detect and data terminal ready.
The RS-232 connector may be
ordered as a male or female 25-pin
connector. Field connection is made
through a modern, solderless,
screw-termination as sem bly.
Alternatively, a con ve nient four-wire
mod u lar phone jack is available.
Interface
LDM70 conforms to EIA RS-232
and CCITT V.24 spec i fi ca tions.
Pins 4 and 5 are internally
connected. Pin 6, Data Set Ready
(DSR), is internally tied to the valid
state through a resistor. Data
Terminal Ready (DTR), pin 20, must
be asserted by the host equipment
before LDM70 can transmit data.
When DTR is asserted, the LDM70
at the other end of the com mu ni cations cable will assert Receive
Line Signal Detect (RLSD), pin 8, to
its host equipment. This is used by
host equipment to coordinate data
ex chang es. If a DTR signal is not
available from the host equipment,
an open circuit on pin 20 will be
equivalent to assertion, allowing
operation without hand shake. Pin 7
is signal ground. Pins 2 and 3 are
switch-reversible.
Isolation
The LDM70 is unique compared to
other popular limited-distance
modems in that it completely
isolates the host equip ment from the
field wiring through the use of
optical couplers and a DC-to-DC
converter. Units that use only optical
couplers break ground loops but
circuit power is still taken from an
unisolated source, and/or host
circuit ground is still connected to
one field wire pair. Thus, even
though the ground loop between the
two pieces of host equipment has
been broken, induced transient
currents will still flow from the field
wiring through the ground circuits of
the host equipment. This can cause
faulty operation of the host
equipment, or even damage in
extreme cases. To prevent this, the
LDM70 models have a transformercou pled DC-to-DC converter which
pow ers the field circuits, with no
path for induced transients to flow
into host equipment. This isolation
barrier is rated to 1000 Vrms.
Continuous operation at high
voltages is not recommended for
safety reasons.
J-12
AVAILABLE FOR FAST DELIVERY!
One Omega Drive | Stamford, CT 06907 | 1-888-TC-OMEGA (1-888-826-6342) | info@omega.com
EPG05
www.omega.com
UNITED KINGDOM
www. omega.co.uk
Manchester, England
0800-488-488
UNITED STATES
www.omega.com
1-800-TC-OMEGA
Stamford, CT.
CANADA
www.omega.ca
Laval(Quebec)
1-800-TC-OMEGA
GERMANY
www.omega.de
Deckenpfronn, Germany
0800-8266342
Karviná, Czech Republic
FRANCE
www.omega.fr
Guyancourt, France
088-466-342
CZECH REPUBLIC
www.omegaeng.cz
596-311-899
BENELUX
www.omega.nl
Amstelveen, NL
0800-099-33-44
More than 100,000 Products Available!
Temperature
Calibrators, Connectors, General Test and Measurement
Instruments, Glass Bulb Thermometers, Handheld Instruments
for Temperature Measurement, Ice Point References,
Indicating Labels, Crayons, Cements and Lacquers, Infrared
Temperature Measurement Instruments, Recorders Relative
Humidity Measurement Instruments, RTD Probes, Elements
and Assemblies, Temperature & Process Meters, Timers and
Counters, Temperature and Process Controllers and Power
Switching Devices, Thermistor Elements, Probes and
Assemblies,Thermocouples Thermowells and Head and Well
Assemblies, Transmitters, Wire
Flow and Level
Air Velocity Indicators, Doppler Flowmeters, Level
Measurement, Magnetic Flowmeters, Mass Flowmeters,
Pitot Tubes, Pumps, Rotameters, Turbine and Paddle Wheel
Flowmeters, Ultrasonic Flowmeters, Valves, Variable Area
Flowmeters, Vortex Shedding Flowmeters
pH and Conductivity
Conductivity Instrumentation, Dissolved Oxygen
Instrumentation, Environmental Instrumentation, pH
Electrodes and Instruments, Water and Soil Analysis
Instrumentation
Data Acquisition
Auto-Dialers and Alarm Monitoring Systems,
Communication Products and Converters, Data
Acquisition and Analysis Software, Data Loggers
Plug-in Cards, Signal Conditioners, USB, RS232, RS485
and Parallel Port Data Acquisition Systems, Wireless
Transmitters and Receivers
Pressure, Strain and Force
Displacement Transducers, Dynamic Measurement
Force Sensors, Instrumentation for Pressure and Strain
Measurements, Load Cells, Pressure Gauges, Pressure
Reference Section, Pressure Switches, Pressure Transducers,
Proximity Transducers, Regulators,
Strain Gages, Torque Transducers, Valves
Heaters
Band Heaters, Cartridge Heaters, Circulation Heaters,
Comfort Heaters, Controllers, Meters and Switching
Devices, Flexible Heaters, General Test and Measurement
Instruments, Heater Hook-up Wire, Heating Cable
Systems, Immersion Heaters, Process Air and Duct,
Heaters, Radiant Heaters, Strip Heaters, Tubular Heaters
click here to go to the omega.com home page
Loading...