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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.  Rather than

duplicate the CRC and risk increasing the overall bit error rate the RTcom protocol leaves your protocol 100% intact

and does not add any further error checking and subsequent time delay to your messages

.

LED's

Status LED's are provided to aid use. On the Global, Universal and Max, the top, green LED indicates

power and the CPU status. If all is well this LED will blink at a regular interval.

The centre amber LED is for received data communications (message received or sent to the data

terminal) by cable.

The bottom red LED indicates the transmission of data.

All LED's Blink

If all LED's should blink together this indicates a data configuration error. This is normally caused by the

data rate, parity etc being incorrect at the transmitting end. The data configuration error mode is

normally triggered by the occurrence of a framing error.

Manual intervention, i.e. changing the dip switches and/or the data terminal will be required.  Note both

ends of the link must share the same configuration.

Only after pressing and releasing the reset button will the configuration become effective.

Summary of Contents for Radio Modems

Page 1: ...User Manual RTcom Universal Global Max and Outback Radio Modems Copyright Radio Tech Limited 1998 2000...

Page 2: ...RTcom Global and Universal 11 RTcom Outback 12 RTcom Max 12 CONNECTIONS Data and Power 13 CONFIGURATION Operating Modes Table for the RTcom range 14 Data format mode switch 15 Interface mode switch 15...

Page 3: ...al Global Europa Outback and Max are numerous These include reduced installation cost the ability to cross awkward terrain cross third parties lands cross rivers and operate from moving objects Polled...

Page 4: ...countries such as the United States also permit unlicensed transmissions under FCC Part 15 but both the power and duty cycle limits imposed make modem operation impractical for reliable operation over...

Page 5: ...nna size dipole 43cm 17cm 17cm 8cm 8cm Potential users in adjacent channels Message pagers Radio Microphones Radio Amateur on 433MHz Radio Amateurs on 433MHz Message Pages on 458MHz and TETRA on 410 4...

Page 6: ...rom its own power supply Hence as a rule of thumb we only recommend the use of linear power supplies Similarly where supply interruption is to be protected against we recommend the use of float charge...

Page 7: ...to a minimum and whenever possible uses the lowest loss cable available Both cables and terminations should always be 50 Ohm impedance Cable bends should no be too tight i e the radius of the bend sho...

Page 8: ...ower supplies The best form of protection is to use a surge arrestor The arrestor is connected in series with the antenna and the modem and is intended to safely limit the induced voltage However a su...

Page 9: ...i antenna vertically polarised In polled systems where there is a central base station the base station will need an omni directional antenna However the outstations may still employ a directional ant...

Page 10: ...w and the dipole can become cumbersome and a compressed dipole helical antenna has to be used Whatever antenna types you choose please ensure that its impedance is 50 Ohms name Gain and Directional Pr...

Page 11: ...12 24V dc supply RS422 RS485 Interface RS232 interface Links to select 2 4 wire RS485 Mode Switch for Data Rate and data format Channel selection switch Global Only See Table Mode Switch for RS232 RS4...

Page 12: ...Max Please take care when opening cover Optional Location for Battery Solar 12 24V dc supply RS422 RS485 Interface RS232 interface Links to select 2 4 wire RS485 Configuration Mode Switch Radio Modul...

Page 13: ...sion All units support 7 and 8 bit ASCII even an odd parity and 1 or 2 stop bits Terminal Number Designation WRT Modem Notes 1 24V dc supply 2 GND Ground 3 12V dc supply 4 GND Ground 5 DTR Optional no...

Page 14: ...er to ensure that the connections are correctly terminated Normally cables with an impedance 100 Ohms should be used and terminating resistors 120R bwtween A B and Z Y may aslo be required CONFIGURATI...

Page 15: ...n RS485 RS422 4 On RS232 Interface Mode switch SW2 Note The Europa is fully electronically programmable Europa users should consult the programming toll on the disk provided with the modem Mode SW1 1...

Page 16: ...s Status LED s are provided to aid use On the Global Universal and Max the top green LED indicates power and the CPU status If all is well this LED will blink at a regular interval The centre amber LE...

Page 17: ...correct communication errors From experience the latency delay caused by error correction techniques is prohibitive for the majority of applications Further the use of a transmit buffer imposes a fin...

Page 18: ...t as they give you control over the priorities We are able to write customer specific programmes and or assist you own software engineers EMC CONFORMATY Finished products placed on the market with the...

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