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ATiM

ATiM. Spécialiste en étude et développement de produits de radiocommunication www.atim.com. ARM-SE «  A dvanced R adio M odem S erial & E thernet ». Agenda. Morning : Theory - Operating Principles Radio Notions Serial Links Notions Network Notions ARM-SE Description

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  1. ATiM Spécialiste en étude et développement de produits de radiocommunication www.atim.com

  2. ATIM: le spécialiste de la radiocommunication ARM-SE « Advanced Radio Modem Serial & Ethernet »

  3. Agenda ATIM: le spécialiste de la radiocommunication • Morning: • Theory - Operating Principles • Radio Notions • Serial Links Notions • Network Notions • ARM-SE • Description • Operating Modes • Radio Settings • Extras • Afternoon: • Workshop

  4. Theory – Operating Principles ATIM: le spécialiste de la radiocommunication Radio Notions

  5. Transmitter Receiver RF Basics ATIM: le spécialiste de la radiocommunication • Basic Communication System • Transmitter and Receiver

  6. Transmitter Antenna 1 Receiver RF Basics ATIM: le spécialiste de la radiocommunication Basic Radio Communication System • Transmitter and Receiver • Transmitting Antenna

  7. Transmitter Antenna 1 Antenna 2 Receiver RF Basics ATIM: le spécialiste de la radiocommunication Basic Radio Communication System • Transmitter and Receiver • Transmitting Antenna • Receiving Antenna

  8. Transmitter Antenna 1 Antenna 2 Receiver RF Basics Environment ATIM: le spécialiste de la radiocommunication Basic Communication System • Transmitter and Receiver • Transmitting Antenna • Receiving Antenna • Environment

  9. Transmitter Transmitter Antenna 1 Antenna 1 Antenna 2 Antenna 2 Receiver Receiver RF Basics Environment Environment ATIM: le spécialiste de la radiocommunication Basic Communication System

  10. RF Basics ATIM: le spécialiste de la radiocommunication

  11. Transmitter Antenna 1 Antenna 2 Receiver RF Basics ATIM: le spécialiste de la radiocommunication Maximizing Range

  12. Increase Power Antenna 1 Antenna 2 Receiver RF Essentials ATIM: le spécialiste de la radiocommunication Maximizing Range • Increase Transmitter (TX) Power • Government Regulated • Low-powered Applications

  13. Increase Power Increase Gain Increase Gain Improve RX Sensitivity RF Essentials ATIM: le spécialiste de la radiocommunication Maximizing Range • Increase Transmitter (TX) Power • Increase Receiver (RX) Sensitivity • Specified in dBm (more of this later)

  14. RF Essentials • Transmitting Antenna • Focused energy • Receiver Antenna • Focused energy ATIM: le spécialiste de la radiocommunication Maximizing Range • Increase Transmitter (TX) Power • Increase Receiver (RX) Sensitivity • Increase Antenna Gain • More gain equates with more focusing of energy • Antenna cables should be as short as possible

  15. Increase Power Increase Gain Increase Gain Improve RX Sensitivity RF Essentials Clear the Environment ATIM: le spécialiste de la radiocommunication • Maximizing Range • Increase Transmitter (TX) Power • Improve Receiver (RX) Sensitivity • Increase Antenna Gain • Clear the Environment of obstructions • Visual (Linear) line-of-sight vs. RF (Radio) line-of-sight

  16. Fresnel Zone RF Essentials ATIM: le spécialiste de la radiocommunication • Fresnel Zone • Football-shaped path

  17. l n d d r = 1 2 n + d d Site A 1 2 3rd* 2nd* 1st* d1 Site B d2 RF Essentials Radius of nth Fresnel Zone given by: * Fresnel Zones Fresnel Zone diameter depends upon Wavelength, and Distances from the sites along axis For minimum Diffraction Loss, clearance of at least 0.6F1+ 3m is required

  18. RF Essentials ATIM: le spécialiste de la radiocommunication • Fresnel Zone • Football-shaped path • Acceptable = 60% of Zone 1 + 3 meters • Raise antennas to help clear the zone

  19. RF Essentials ATIM: le spécialiste de la radiocommunication Fresnel Zone Diameters

  20. RF Terminology ATIM: le spécialiste de la radiocommunication RF starts with AC (Alternating current) The antenna converts radio frequency electrical energy fed to it (via the transmission line) to an electromagnetic wave propagated into space.

  21. RF Terminology Wavelength = 3 x 108 868MHz -> 34.5 cm f (frequency in Hz) ATIM: le spécialiste de la radiocommunication Wavelength is the distance between identical points in the adjacent cycles of a waveform. In wireless systems, this length is usually specified in meters, centimeters, or millimeters The size of the wavelength varies depending on the frequency of the signal. Generally speaking, the higher the frequency the smaller the wavelength.

  22. RF Terminology ATIM: le spécialiste de la radiocommunication • Frequency • Measured in Hz (Hertz) • With appropriate multiplier • kHz – Kilohertz (Thousands of Hertz) • MHz – Megahertz (Millions of Hertz) • GHz – Gigahertz (Billions of Hertz) • Frequency Classification • VLF – Very Low Frequency 10-30kHz • LF – Low Frequency 30-300kHz • MF – Medium Frequency 300-3000kHz • HF – High Frequency 3-30MHz • VHF – Very High Frequency 30-300MHz • UHF – Ultra High Frequency 300-3000MHz • SHF – Super High Frequency 3-30GHz • EHF – Extremely High Frequency 30-300GHz

  23. RF Terminology ATIM: le spécialiste de la radiocommunication • Tx is short for “Transmit” • All radios have a certain level or Tx power that the radio generates at the RF interface. This power is calculated as the amount of energy given across a defined bandwidth and is usually measured in one of two units: • dBm – a relative power level referencing 1 milliwatt • W – a linear power level referencing Watts dBm = 10 x log[Power in Watts / 0.001W] W = 0.001 x 10[Power in dBm / 10 dBm]

  24. RF Terminology ATIM: le spécialiste de la radiocommunication Rx is short for “Receive” All radios also have a certain ‘point of no return’, where if they receive a signal less than the stated Rx Sensitivity, the radio will not be able to ‘see’ the data. This is also stated in dBm or W.

  25. RF Terminology ATIM: le spécialiste de la radiocommunication • In a wireless system, antennas are used to convert electrical waves into electromagnetic waves. The amount of energy the antenna can ‘boost’ the sent and received signal by is referred to as the antennas Gain. • Antenna gain is measured in: • dBi: relative to an isotropic radiator • dBd: relative to a dipole radiator 0 dBd = 2.15 dBi

  26. RF Terminology ATIM: le spécialiste de la radiocommunication • Omni-Directional • Shorter Distances • Greater Coverage • Directional • Greater Distances • Area coverage sacrificed

  27. Antenna Gain • Antenna Gain • (dBi) • (dBi) • A • B • Path Loss (dB) • Field Factor (dB) • Connector • Connector • Losses • Losses • (dB) • Cable Losses • Cable Losses • (dB) • (dB) • (dB) • Tx Output (dBm) • Tx Output (dBm) • Received Signal Level • (dBm) = Tx Output (dBm) - Path • Loss(dB) - Field Factor (dB) + Total Antenna Gains (dB) - Total • Cable Losses (dB) - Total Connector Losses (dB) RF Calculations ATIM: le spécialiste de la radiocommunication Link Budget Calculations

  28. TRANSMISSION POWER ATTENUATION BY AIR RECEIVER SENSITIVITY 4800 Bauds 5 mW 7 dBm 0,5km -81 dBm -112 dBm 9600 Bauds 25 mW 14 dBm 1km -91 dBm -110 dBm 19200 Bauds 500 mW 27 dBm 2 km -97 dBm -107 dBm 3 km -101 dBm 38400 Bauds -104 dBm Table 3 4 km -103 dBm 76800 Bauds -101 dBm 5 km -105 dBm Table 5 6 km -107dBm 7 km -108 dBm Table 4 RF Calculations ATIM: le spécialiste de la radiocommunication ARM-SE Example

  29. RF Regulations ATIM: le spécialiste de la radiocommunication • Regulatory Bodies • FCC (United States) • IC (Canada) • ETSI (Europe, some APAC) • C-Tick (Australia) • Telec (Japan) • Anatel (Brazil)

  30. RF Regulations ATIM: le spécialiste de la radiocommunication

  31. RF Modulation Data Carrier Modulated Signal ATIM: le spécialiste de la radiocommunication • Modulate • Insert data signal into a carrier wave. • Digital data. 0 or 1 • RF Modulation • Transmitting a signal within a carrier frequency by blending an alternating frequency or amplitude onto the carrier wave

  32. Theory – Operating Principles ATIM: le spécialiste de la radiocommunication Serial Link Notions

  33. Serial Links - RS-232 ATIM: le spécialiste de la radiocommunication Architecturally RS-232 is a bi-directional point to point link. RS-232 is a popular communications interface for connecting modems and data acquisition devices (i.e. GPS receivers, electronic balances, data loggers, ...) to computers. RS-232 can be plugged straight into the computer’s serial port (know as COM or Comm port).

  34. Serial Links - RS-232 ATIM: le spécialiste de la radiocommunication Two independent channels are established for two-way (full-duplex) communications. RS-232 can also carry additional signals used for flow control (RTS, CTS) and modem control (DCD, DTR, DSR, RI).

  35. Serial Links - RS-232 ATIM: le spécialiste de la radiocommunication • Unbalanced Line Drivers • Each signal appears on the interface connector as a voltage with reference to a signal ground. • The “idle” state (MARK) has the signal level negative with respect to common whereas the active state (SPACE) has the signal level positive respest to the same reference.

  36. Serial Links - RS-232 ATIM: le spécialiste de la radiocommunication • How fast can RS-232 be? • The maximum speed, according to the standard, is 20kbit/s.However, modern equipment can operate much faster than this. • The length of the cable also plays a part in maximum speed.The longer the cable the slower the speed at which you can obtain accurate results.A large wire capacitance and inductance limits the maximum length of the cable and/or the maximum speed; Moreover higher is the capacitance of the cable higer is the interference between two adjacent signal wire.15m @ max baudrate is commonly quoted as the maximum distance.

  37. + 25 - 25 Serial Links - RS-232 • Stop bits = 1 (or 2) • Parity = NONE (or EVEN or ODD) ATIM: le spécialiste de la radiocommunication • SW Settings • One byte of async data has: • Start Bit = 1 (always) • Data Bits = 8 (or 7)

  38. Serial Links - RS-485 ATIM: le spécialiste de la radiocommunication • What is RS-485? • RS-485 is a EIA standard interface which is very common in the data acquisition world • RS-485 provides balanced transmission line which also can be shared in Multidrop mode. • It allows high data rates communications over long distances in real world environments. • How fast can RS-485 be? • RS-485 was designed for greater distance and higher baudrates than RS-232. • According to the standard, 100kbit/s is the maximum speed and distance up to 4000 feet (1200 meters) can be achieved.

  39. Serial Links - RS-485 ATIM: le spécialiste de la radiocommunication • Balanced Line Drivers • Voltage produced by the driver appears across a pair of signal wires that transmit only one signal. Both wires are driven opposite. • RS-485 driver has always the “Enable” direction control signal. • Differential system provides noise immunity, because much of the common mode signal can be rejected by the receiver. So ground shifts and induced noise signals can be nullified.

  40. SLAVE-1 MASTER SLAVE-2 SLAVE-3 Serial Links - RS-485 • The standard specifies up to 32 drivers and 32 receivers can share a multidrop network • Terminator resistors avoid reflected signal ATIM: le spécialiste de la radiocommunication • RS-485 Network • RS-485 provides Half-Duplex, Multidrop communications over a single twisted pair cable.

  41. TX485+ TX485- TX ENABLE RX TX ENABLE RX RX485+ RX485- 485GND Other device Serial Links - RS-485 ATIM: le spécialiste de la radiocommunication • RS-485 Full-duplex • Potentially RS-485 interface can also use 4-wires to comunicate in multidrop mode but...

  42. Serial Links ATIM: le spécialiste de la radiocommunication • RS-232 vs RS-485 • The architectural difference between RS-232 and RS-485 is that 232 is a bi-directional point to point link, whereas 485 is a single channel bus. • Electrically, each 232 signal uses a single wire with symmetric voltages about a common ground wire. 485 uses two wires to carry the single signal differentially. • The big difference to the software is that only one device on a 485 bus can transmit at a time, whilst there is not similar limitation on RS232 because is a peer-to-peer link .

  43. Theory – Operating Principles ATIM: le spécialiste de la radiocommunication Network Notions

  44. Network Notions ATIM: le spécialiste de la radiocommunication Internet is a global system of interconnected computer networks that use the standard Internet Protocol Suite (TCP/IP)

  45. Network Notions Different network types interconnected. = don’tdepend of lowlevellayers. ATIM: le spécialiste de la radiocommunication TCP/IP stack is base in the OSI model

  46. Network Notions – TCP/IP Client <->Master Server <-> Slave Successive encapsulation of datas from application to physical network access. ClientServer ATIM: le spécialiste de la radiocommunication Encapsulation:

  47. Network Notions – TCP/IP ATIM: le spécialiste de la radiocommunication • PhysicalAddressing: • NIC (Network Interface Controller)= address of lowlevellayers • Each NIC has a MAC address (6 bytes) • AddressResolution: • The communication between 2 equipmentsstarts by a MAC resolutionaddress. • Example: arp = MAC resolutionfrom an IP address • Needs a frame « all access » for queryeveryone and wait for reply • Frame « all access» has @MAC dest « Broadcast » (FF-FF-FF-FF-FF-FF)

  48. Network Notions – TCP/IP PHY: Radio, Cable, Optical fibers MAC: (CSMA/CD, CSMA/CA, Token ring, RTS/CTS etc...) CSMA /CD Token Ring Wireless ATIM: le spécialiste de la radiocommunication Physical & standard layers:

  49. Management of the lowlayers By ARM-SE: ATIM: le spécialiste de la radiocommunication

  50. Network Notions Applications managed by ARM-SE server: HTTP: embedded web pages ModBusTCP Server: decapsulateModBus RTU message Bootloader: Firmware upgrade service Destination MAC addressesfiltering (to reduce the wireless Ethernet trafic) ExceptBroadcastaddressing ! ATIM: le spécialiste de la radiocommunication

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