USER MANUAL RTcom–Universal, Global, Europa and Outback Radio Modems Distributor: Wessex Power Technology Ltd 189 Ashley Road, Parkstone Poole, Dorset, BH14 9DL Tel: +44 (0)1202 723000 Fax: +44 (0)1202 723400 Email: wpt@wessexpower.co.uk www.wessexpower.co.
CONTENTS INTRODUCTION Selecting the frequency of operation 4 R.
INTRODUCTION The RTcom range of radio modem is intended as a direct replacement for cables over short, medium and long distance serial data links. They are suitable for point-to-point, master to slave or scanning telemetry links, where the modem is either used on its own or in conjunction with existing cables. The modems also operate transparent to many industry standard network protocols, such as MODBUS and EIBA Bus and can be used with many manufacturers PLC communication protocols.
Frequency of operation : Often, there is not a choice over operating frequency. In most countries, frequency allocations are very Limited. By way of example, in Europe there is only 433-435MHz UHF or 868-870MHz SHF, while the UK and many others offer extra VHF, UHF and SHF allocations. However, other frequencies may be used subject to local government licence.
Un-Licenced Operation : In many countries, it is quite legal to operate systems without the need for operating licences. These countries include the United Kingdom, Australia, New Zealand, Korea, South Africa, Scandinavia, and the majority of Europe.
INSTALLATION Power Supplies : As with any radio communications system, the RTcom modem should be connected to a clean and stable supply. Switch mode power supplies are rich in RF harmonics and should not be used. Please note that in many cases, a CE sticker on a power supply is insufficient protection against potentially damaging harmonics. The reality is that the EMC pass limits are set at only -57dBm (31uV), whereas a radio is quite capable of operation down to and beyond -115dBm (0.5uV).
Antenna Feeders : The basic rule of thumb is the greater the length of cable, the greater the loss. Always attempt to keep cable runs to a minimum and whenever possible, use the lowest loss cable available. Both cables and terminations should always be of 50 Ohm impedance. Cable bends should not be too tight i.e. the radius of the bend should be greater than 10 x the diameter of the cable. It is important to remember that coaxial cables have losses proportional to their length and quality.
Antenna Installation : The type and location of the antenna used can have a profound effect on your overall system performance and its legality. In point to point links, it is good practice to make efficient use of the radio spectrum by selecting an antenna that will project the RF energy into the direction of desired operation and similarly at the receiver to collect transmissions only from the location of the transmitter.
Antenna Options : Antenna types fall to a number of categories. For the majority of applications, the choice lies between portable, fixed, omni-directional and those with gain and directional properties. True omni-directional antenna in reality do not exist, i.e. those with equal gain in all directions. However, the nearest practical equivalent is the 1/2 or 1/4 wave dipole. The 1/4 wave dipole is by far the most popular of all antennas and is found in use on most portable apparatus.
GENERAL ARRANGEMENT Guide to your RTcomTM - Global and Universal (Global Illustrated) Carrier Detect LED (Global Only) Channel selection switch (Global Only, See Table) Reset Button Mode Switch for RS232/ RS485 Modes Status LED’s Mode Switch for Data Rate and data format 12-24V dc supply (12V only for MAX) RS232 interface RS422 & RS485 Interface
Guide to your RTcom - Outback Configuration Mode Switch Links to select 2-4 wire RS485 Solar/ 12-24V dc supply RS422 & RS485 RS232 interface Interface
CONNECTIONS Data and Power : Data connections should always be made using screened cable. This will ensure maximum rejection of interference from outside interfering sources. Always use a common ground point. The RTcom Global, Europa and Outback modems support RS232, RS422 and RS485 communications, both 2 and 4 wire. The RS232 port should be used for short cable runs of up to 10m and the RS422 and RS485 can be used for extended distances.
Data and Power cont'd : Pin number 1 Designation WRT Modem DCD 2 RX (data) 3 TX (data) 4 RTS 5 6 7 8 9 10 11 12 13 GND B = RX (-) A = RX (+) +Vs N/C GND Z = TX (-) Y = TX (+) +Vs 14 15 GND +Vs Notes Optional not normally needed RS232 input data to modem RS232 output data from modem Optional not normally needed Ground RS485 / RS422 “ Supply 7.5 to 15V dc No Connection Ground RS485/RS422 “ Optional supply connection Optional Optional supply connection Tab.
CONFIGURATION Operating Modes : Depending upon the model of the modem you will be able to select one of the communication configurations listed below :- VHF : MPT1328 RTcom-Outback 1200-2400bps 7 & 8 bit ASCII Even & odd parity 1 or 2 stop bits UHF : MPT1329 RTcom-Outback 1200-4800bps 7 & 8 bit ASCII Even & odd parity 1 or 2 stop bits UHF: MPT1329 RTcom-Global 2400-9600bps 7 & 8 bit ASCII 7 & 8 bit ASCII 1 or 2 stop bits Tab.
Data Rate : Mode SW1,1 OFF ON OFF ON Mode SW1,2 OFF OFF ON ON Data RateUniversal 2 9600 bps 19200 bps 38400 bps 57600 bps Date RateGlobal 2400 bps 4800 bps 9600 bps 9600 bps Data Rate - Global 1200 1200 bps 2400 bps 4800 bps 4800 bps Tab. 7 : Date Rate setting table subject to version constraints listed above.
Test modes : Test modes are provided to assist installation. Whenever test mode is selected the modem will produce a test transmission to aid both antenna alignment and propagation tests. Mode SW1, 7 OFF OFF ON ON Mode SW1, 8 OFF ON OFF ON RTcom Universal No test mode TESTMODE 1 TESTMODE 2 TEST MODE 1 RTcom Global No test mode TESTMODE 1 TEST MODE 3 TEST MODE 1 RTcom Global 1200 (special) No test mode TESTMODE 1 TEST MODE 2 TEST MODE 1 Tab.
OPERATION The RTcom™ protocol permits 100% transparent operation and direct cable emulation. Simply what goes in comes out! R.F packet framing, code balancing, encryption and preambles etc are taken care of automatically within the modem. Standard industrial communications protocols such as MODBUS include a secure CRC 16 or 32 error check code on data transfers and will probably already be in use over your link, particularly if you are linking PLC’s.
COMMISSIONING The data rate, parity and number of data bits are set using the dual in line switch located above. If a scanner is available the chosen channels and the adjacent channels should be scanned for activity. With frequency agile products such as the -Global, a free channel should be selected as far away as possible form the channel/s in use. The antenna should be positioned and one modem connected and set to test mode. The scanner should be used to measure the received signal strength.
EMC CONFORMITY Finished products placed on the market within the EU must be EMC Type examined. Where applicable, the RTcom-Modems have been Type examined in their own right or contain a Type Examined radio transceiver module. Where applicable a Type Examination / EMC Declaration of conformity will be attached to this manual. Copyright Radio –Tech Limited 1998 – 2002 All information is given in good faith. Equipment should not be used where failure could result in loss of life or damage to the environment.
Specification – General European 433.xxx MHz (ETS 300 220) Model (ROM 3802-0083 and ROM 5501_01) CHANNEL CENTRE FREQUENCY (MHz) S1/1 S1/2 S1/3 S1/4 S1/5 S1/6 433.075 433.100 433.125 433.150 433.175 433.200 433.225 433.550 433.275 433.300 433.325 433.350 433.375 433.400 433.425 433.450 433.475 433.500 433.525 433.550 433.575 433.600 433.625 433.650 433.675 433.700 433.725 433.750 433.775 433.800 433.825 433.850 434.000 434.025 434.050 434.075 434.100 434.125 434.150 434.175 434.200 434.225 434.
PROM Specification – UK 458.xxx MHz (MPT1329) Model (ROM 3802-0084 Issue 1 for DTR 100) CHANNEL CENTRE FREQUENCY (MHz) S1/1 S1/2 S1/3 S1/4 S1/5 S1/6 458.700 458.775 458.750 458.775 458.525 458.550 458.575 458.600 458.625 458.650 458.675 458.700 458.725 458.750 458.775 458.525 458.550 458.575 458.600 458.625 458.650 458.675 458.700 458.725 458.750 458.775 458.525 458.575 458.625 458.675 458.725 458.775 458.750 458.725 458.700 458.675 458.650 458.625 458.600 458.575 458.550 458.525 458.550 458.
