C-1
Wireless Transceiver with
Modbus Interface
The OMWT-XREC-MOD Wireless Transceiver uses
an embedded 100-milliwatt frequency hopping
wireless modem that provides communication
between a local RS-485 network and a remote
network of RS-485 connected devices. The OMWT-
XREC-MOD will automatically sense the direction of
data flow and switch the RS-485 and radio devices
accordingly. The OMWT-XREC-MOD can be placed
in a network of RS-485 devices and appear as a
slave repeater of remote RS-485 devices or it can be
placed in a network of one or many RS-485 slaves
and act as the RS-485 repeater of a remote master.
The radio operates within the 900 MHz ISM Band
under Part 15 of the FCC Rules and regulations.
The OMWT-XREC-MOD operates at 19200 Baud
at either odd parity or no parity. Dip switches select
parity and one of 7 radio networks. Radios operating
together must have the same radio network address
(1-7 set by switches labeled A0-A2). Select a different
radio network address to prevent interference from
nearby networks that are not sharing information.
The default radio network for roof-top applications is
5. The user may choose another network address
(1-7) if desired. While all radios in a network must
have the same network address they do not have to
have the same parity; the parity is local to the RS-485
serial port on the OMWT-XREC-MOD only. Parity
information is not transmitted or received.
Radio network selection 0 (A0, A1, A2 all set to 0)
selects a special network setup. When network
address setting 0 is selected the pre-programmed
radio network parameters are used; these parameters
are user and application specific and must be set at
the factory for specific applications.
The OMWT-XREC-MOD can also be used as a
general purpose RS-485 half duplex radio interface
operating at 19200 baud at either odd or no parity
(dip switch selectable).
The OMWT-XREC-MOD is supplied standard with
a 1/2 wave monopole antenna. For longer distance
outdoor use, optional Omni-Directional and YAGI
directional line-of-site antennas are available.
Specifications
Frequency Range: 902 to 928 MHz,
unlicensed ISM Band
Type: Frequency hopping spread spectrum
transceiver
Frequency Control: Direct FM
Transport Protocol: Transparent networking
Network Topology: Multi-drop
Channel Capacity: Hops through 25 channels,
up to 65,000 NetIDs
OMWT-XREC-MOD
Starts at
$
400
⻬ RS-485 Master/Slave
Auto-Sensing Radio
Interface
⻬ Receives Data from
OMWT-REP-900
Wireless Repeater
⻬ Provides Remote
Capability to RS-485
Modbus Networks
⻬ Built-in 900 MHz
Frequency Hopping
Radio for Long-Range
Wireless Interface
⻬ Multiple Radios Allow
Many Remote RS-485
Networks to Coexist
Logically
OMWT-XREC-MOD, $400,
shown smaller
than actual size.
C-2
C
Each wireless transceiver includes
1
⁄
2
wave antenna and 110 Vac adaptor.
* Additional antennas are availalble. Contact the Data Acquisition Engineering Department.
Ordering Example: OMWT-XREC-MOD wireless transceiver with Modbus interface, $400.
To Order
(Specify Model Number)
Model No. Price Description
OMWT-XREC-MOD $400 Wireless transceiver with Modbus interface
OMWT-OMNI-900-20 330 900 MHz omni-directional antenna
with 6 m (20') cable*
OMWT-YAGI-900-20 330 900 MHz YAGI antenna with 6.1 m (20') cable*
AVAILABLE FOR FAST DELIVERY!
Serial Data Interface:
Asynchronous (RS-232) CMOS
(TTL) signals, 5V, 3.3V tolerant
I/O Data Rate: 9600 baud
Channel Data Rate:
10K bps at 9600 baud
Transmit Power Output: 100mW
Rx Sensitivity: -110 or -107
respectively
Transceiver Range Indoor (with
Standard 1/2 Wave Monopole
Antenna): 180 to 450 m
(600 to 1500'), 900 MHz;
Transceiver Range Outdoor
(With Optional Omni-Directional
Antenna):
Up to 7 mi (11 km), 900 MHz
Transceiver Range Outdoor
(with Optional YAGI Antenna):
Up to 20 mi (32 km), 900 MHz
Interference Rejection:
70 dB at pager and cellular
phone frequencies
Power: 5 Vdc ±0.3V, 170 mA
nominal transmitting, 50 mA
nominal receiving
Operating Temperature:
0 to 70°C (32 to 158°F)
Storage Temperature:
0 to 70°C (32 to 158°F)
Operating Humidity:
10 to 90% RH non-condensing
Dimensions
(Without Antenna):
70 x 127 x 35 mm D
(2.75 x 5.00 x 1.375")
Weight: 142 g (5 oz)
OMWT Series Wireless Transmitters with Modbus Receiver
High Power 900 MHz System with Modbus Receiver
OMWT Series
Wireless Transmitter
OMWT Series
Wireless Transmitter
OMWT Series
Wireless Transmitter
OMWT-REP-900
Repeater, $455
OMWT-XREC-MOD
Modbus Receiver
PC Running User’s
Custom SCADA Software
OMWT Series wireless transmitters can send data to a computer running third
party SCADA software up to 20 miles away using the OMWT-REP-900 repeater
and OMWT-XREC-MOD modbus transceiver.
*Indoors (with 1/2 wave antenna, conditions allowing): up to 1500 ft (900 MHz)
Outdoors (with Omni-directional antenna, conditions allowing):
up to 7 mi (900 MHz)
Outdoors (with YAGI antenna, conditions allowing): up to 20 mi (900 MHz)
serial cable
As many as 100 transmitters can be used