SCADA Telecommunications Data Integrity. Michael L. Watson Rapid Technologies Intl, Ltd. Michael L. Watson. B.S.E.E. Texas ASU 20+ Years Industry experience Teaching AGA Measurement, Communications, and Microsoft Windows courses since 1998 Full partner Rapid Technology Intl
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Michael L. Watson • B.S.E.E. Texas ASU • 20+ Years Industry experience • Teaching AGA Measurement, Communications, and Microsoft Windows courses since 1998 • Full partner Rapid Technology Intl • Currently consulting in 5 Countries • Committee service for GPA, ANB, ONIP
Definitions • 1. Telephone (Dialup/Lease), Cellular, Radio,Microwave Physical mediums for data transmission. • 2. Radio The wireless transmission through space of electromagnetic waves in the approximate frequency range from 10 kilohertz to 300,000 megahertz. • 3. Modem A device for transmitting usually digital data over telephone wires by modulating the data into an audio signal to send it and demodulating an audio signal into data to receive it. • 4. Protocols A standard procedure for regulating data transmission between computers.
Telemetry Methods • Conventional Radio • Trunking Radio • SpreadSpectrum Radio • Motorola DataTAC • Serial Cable • Dial Up • Serial Multi-Drop • Leased-Line • Internet IP • Ethernet TCP/IP, UDP/IP • TCP Pooling • TCP Listen • Terminal Server (TCP/IP, UDP/IP) • Satellite • VSAT • PSTN • CDPD • CDMA • GPRS
Definitions • Baud rate Pronounced bawd, the number of signaling elements that occur each second. The term is named after J.M.E. Baudot, the inventor of the Baudot telegraph code. Actually BPS. For a more true indication of baud rate, the rule of thumb is to divide bps by 10 • Parity The quality of being either odd or even. The fact that all numbers have a parity is commonly used in data communications to ensure the validity of data. This is called parity checking. • CRC Cyclic Redundancy Check, another common technique for detecting data transmission errors.Data is checked against a known fomula. • Checksum A simple error-detection scheme in which each transmitted message is accompanied by a numerical value based on the number of set bits in the message.
9600,8,N,1What does it mean ? • Baud rate 1200, 2400, 4800, 9600, 19200,…115200 • Word bits 7 or 8 • Parity Even, Odd, None • Stop bits 0, 1, or 2
Bits and Bytes • Bit = 0 or 1 (One of only two values) • Byte = 8 bits (Max. number = 255) • Character = Any 8 bit or 1 byte value • Word = 8 bit CPU = 8 bit word 16 bit CPU = 16 bit word • Float = Can be 16 bit (1 byte) or 32 bit (2 byte) Normally 32 bit int. = HB/LB HW/LW • Rev. Float = Can be 16 bit or 32 bit Normally 32 bit int. = HB/LB LW/HW
Byte and word ordering • Each 16-bit register - two 8-bit bytes • High byte/Low byte • Low byte/High byte • Each 32-bit number - two 16-bit registers (called words) • High word/Low word • Low word/High word
Byte and word ordering • 32-bit integer (4 bytes - 2 words) • decimal 2,309,737,967 • hex 89 AB CD EF • binary 10001001 10101011 11001101 11101111 - Most significant comes first - High byte/Low byte - High word/Low word - Big Endian (big end first)
Byte and word ordering • 32-bit integer (4 bytes - 2 words) • decimal 2,309,737,967 • hex EF CD AB 89 • binary 11101111 11001101 10101011 10001001 - Most significant comes last - Low byte/High byte - Low word/High word - Little Endian (little end first)
Big-Endian and Little-Endian • Terms derived from the Lilliputians of Gulliver's Travels • their major political issue was whether soft-boiled eggs should be opened on the big end or the little end. • Likewise, the big-/little-endian computer debate has much more to do with political issues than technological merits.
Common Big Endian file formats • Motorola • Adobe Photoshop -- Big Endian • IMG (GEM Raster) -- Big Endian • JPEG -- Big Endian • MacPaint -- Big Endian • SGI (Silicon Graphics) -- Big Endian • Sun Raster -- Big Endian • WPG (WordPerfect Graphics Metafile) -- Big Endian (on a PC!) • TIFF --Both, Endian identifier encoded into file • DXF (AutoCad) --Variable
Common Little Endian file formats • Intel • BMP (Windows and OS/2 Bitmaps) -- Little Endian • GIF -- Little Endian • FLI (Autodesk Animator) -- Little Endian • PCX (PC Paintbrush) -- Little Endian • QTM (Quicktime Movies) -- Little Endian (on a Mac!) • Microsoft RTF (Rich Text Format) -- Little Endian • TGA (Targa) -- Little Endian • Microsoft RIFF (.WAV & .AVI) -- Both • XWD (X Window Dump) -- Both, Endian identifier encoded into file
Protocol Defined • A standard procedure for regulating data transmission between computers. • An agreed-upon format for transmitting data between two devices. The protocol determines the following: • the type of error checking to be used • data compression method, if any • how the sending device will indicate that it has finished sending a message • how the receiving device will indicate that it has received a message • There are a variety of standard protocols from which programmers can choose. Each has particular advantages and disadvantages; for example, some are simpler than others, some are more reliable, and some are faster. • From a user's point of view, the only interesting aspect about protocols is that your computer or device must support the right ones if you want to communicate with other computers. • The protocol can be implemented either in hardware or in software.
Numeric Data Types BOOLEAN 1 bit 0 or 1 INTEGER 16 bits HB LB (-32768 to 32767) UINTEGER 16 bits HB LB (0 to 65535) LONG1 32 bits HB LB / HW LW (-2.1 to 2.1 billion) LONG2 32 bits HB LB / LW HW (-2.1 to 2.1 billion) ULONG1 32 bits HB LB / HW LW (0 to 4.2 billion) ULONG2 32 bits HB LB / LW HW (0 to 4.2 billion) FLOAT1 32 bits HB LB / HW LW - IEEE Floating point FLOAT2 32 bits HB LB / LW HW - IEEE Floating point - reverse float
Data Types - ASCII Strings Each character is one 8-bit byte Two characters per register Name size attributes STRING4 32 bits String of 4 chars (2 registers) STRING8 64 bits String of 8 chars (4 registers) STRING12 96 bits String of 12 chars (6 registers) STRING16 128 bits String of 16 chars (8 registers) STRING124 992 bits String of 124 chars (62 registers) STRING128 1024 bits String of 128 chars (64 registers)
Time and Date Types Name size attributes CCYY 16 bits Year as two 8-bit integers MMDD 16 bits Date as two 8-bit integers HHMM 16 bits Time as two 8-bit integers YEAR 16 bits Year as one 16-bit integer MONTH 16 bits Month as one 16-bit integer (1-12) DAY 16 bits Day as one 16-bit integer (1-31) HOUR 16 bits Hour as one 16-bit integer (0-23) MINUTE 16 bits Minute as one 16-bit integer (0-59) SECOND 16 bits Second as one 16-bit integer (0-59)
Time and Date Types Name size -type description DAY1970 32 bit int HW LW Days since Jan 1, 1970 DAY1970_R 32 bit int LW HW Days since Jan 1, 1970 MSECMID 32 bit int HW LW Milliseconds since midnight MSECMID_R 32 bit int LW HW Milliseconds since midnight TIME1970 32-bit Float HW LW Days since Jan 1, 1970 TIME1970_R 32-bit Float LW HW Days since Jan 1, 1970 - decimal is time of day ± 1.4 minutes TIME1900 32-bit Float HW LW Days since Jan 1, 1900 TIME1900_R 32-bit Float LW HW Days since Jan 1, 1900 - decimal is time of day ± 5.6 minutes
Enron MODBUS History Modbus Reply: 01 03 14 04DBBC00 47EAF800 43C8EEAD | | | | | | | | | | | 1st item logged (401.86) | | | | Record Time 32-bit Float | | | Record Date 32-bit float | | data bytes to follow (14 hex = 20 decimal) | function code (03 = read holding registers) Modbus address 4400436B 4287FFFF 221C | | | | | CRC | 3rd item logged (68.00) 2nd Item logged (513.05)
DCS, SCADA, MMI, HMIWhat does it all mean? • DCS Direct Control System (Full Control of a system) • SCADA Supervisory Control And Data Acquisition (Supv. Control of a system) • MMI Man Machine Interface • HMI Human Machine Interface A machine interface is just the layer that separates the user (human) from the machine (Computer). Man vs. Human is simply a political issue.
PC HMI COM1 EFM Historical Database RS232 COM2 RS232 RADIO EFM RADIO EFM RS232 EFM RS485/23 2 EFM RS485
PC Host Program Historic al Data Te xt Impor ter COM1 EFM File s AES Historical Database RS232 Ser ver Rea l T ime Data COM2 DDE HMI Soft ware RADIO RS232 or Excel EFM RADIO EFM RS232 EFM RS485/23 2 EFM RS485
PC HMI Proprietary Converter Historic al Data Te xt Impor ter COM1 EFM File s Historical AUTOSOL Database RS232 Ser ver Rea l T ime Flow-Cal Data (Enron Mod) COM2 DDE Edit Soft ware RS232 Fiber Con Historical Database EFM Fiber Con EFM RS485 EFM RS485/23 2 EFM RS232
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