ML20203K697

Rev O to Radiation Monitoring Sys Protocol Tss

ML20203K697
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Site:	San Onofre
Issue date:	07/07/1995
From:	Edelman M, Lopez S, Purpura G SOUTHERN CALIFORNIA EDISON CO.
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Text

ENCLOSURE 2 RADIATION MONITORING SYSTEM PROTOCOL TECitNICAL SPECIFICATIONS p PDR

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PGD-00082 / REVISION O PGD00082. DOC TABLE OF CONTENTS Page 1.0 Attachment A - lL1GP Document M5866BA, RMS Protocol Technical

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g MGP annmanns RMS Protocol Technk:al Specifications Radiatbn Monitonng System p3 Update Table IndexIDate Modified pages Origin and designation of the Written by modification B + 06/06/95- NAJ All Merhn Gerin Provence changed to MG Instrurnents p15 Exception code clarification p23 pt2 The protocolaccepts 2 stop bits p27 No response time-out is speed dependant Changed crossed cable to straight cable

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$ MGP annuges MS ProtocolTechnient SpecMcations Radiation Monitoring System p4 Table o content

1. I ntrod u ctio n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Purpose.......................................................................................................4 1.2. Scope...........................................................................................................4 1.3. Definitions, Acronyms and Abbreviations ..................................................... 5 1.4. R efe re n ce s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.5. Overview......................................................................................................5

2. Protocol definition . .. . . . . . ... . . . . . . . .. . . . . .. .. . . . ... . . . . . . ... .. . . . .. . . ... . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . .. 6 2.1. I ntrod u ctio n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2. Exchange characterization .... .... . . ............ ..... ............. . ....... ........ .. .. ... ... . .. ..... . 9 2.3. Timing chara cterization ...... .. ..... ....... .... ..... .... . .. . .. .... ... . . . . ....... ... . ..... ....... .. 10 2.3.1. Exchange synchronization: ...................................................... ... 10 2.3.2. Network load analysis ...... ....... .. . . .. .... .. ...... . . ... . .. ...... .. .... .. ...... . ... . ... . 11 2.3.3. Maximum exchange duration ......................................................... 12 2.4. Request and response frame presentation .................................................. 13 2.5. Slave received message control ................................................ .................. 14 2.5.1 Message control process ................ ........ ... .. .. ... . .. ..... .. .. . ....... .........,14 2.5.2. Exception message content ........... .. . .......... .... . ...... .... . .... ... ... ... . .. . .. 15 2.6. Data represe ntation . . . .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . .. . . . . . . .. . .. . . . . 16 2.6.1 Byte (or character) representation ...................................... ........... 16 2.6.2, Word representation ...... ..................... .. .................................. ....... 16

3. Protocol fu nctions .... ... . . . . . . .. .. . . . . . . ..... . .. . .. . . . . . . . . .. . . ... . . . . . . . . . . . . . . . .. . . . . . . .. . ... . . . . . . .. . .. .. . . .. . . .. .. .. 17 3.1. Multiple word reading: function 3 or 4........................................................... 17 3.2. Word writing: function 6.. ...... .............. .... ..... . . .. .... ... ..... .......... ..... ...... . ........... 18 3.3. Diagnosis counter reading: function 8 .......................................................... 19 3.4. Event counter reading: function 11............................................................... 20 3.5. Multiple word writing: function 16 ................................................................. 21

3. C o m m u nication setting s .. .. ... .. ... . . ... . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . . .. . . . .. .. ..... . . . . . . . . . 2 3

4. H ardwa re interface . . .. . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . .. . . . . . . . .. . . . . . . . . . . ... . . . . . . . . .. . . . .. . . . . . . . . . . . . . . . . . . . . . . . . 24 4.1. RS485 M ultidrop interface ..... ......... ...... ........ . ........ ... ...... ...... ....... ...... ......... .. 24 4.2. RS232 point-to-point interface...................................................................... 27 Appendix A: C RC 16 alg o rithm . .. .. . .. . . . . . . . . . .. . . . . .. . .. .. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . .... . . . .. . . 2 9 s

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guannuannMGP Radiation Monitoring System RMS Protocol Technical Specifications p5

1. Introduction l

1.1. Purpose All units of the Radiation Monitoring System integrate digital communication links to be able to communicate between each other. Each unit has its own data stored in a parameter table that is shared between the unit itself and an extemal device (as a master unit, or a computer).

To allow extemal devices to read and/or write into this parameter table, each unit integrates a communication protocol compatible with MODBUS/JBUS.

The purpose of this document is to describe this protocol as used in RMS. A unit that wants to be connected to the Merlin Gerin Radiation Monitoring System, using embedded protocol, shall comply with these specifications.

Additional documents will be written for optional communication protocols that may be implemented on extension boards.

1.2. Scope This technical specification concems the whole Radiation Monitoring System project since each unit manages an embedded protocol compatible with MODBUS.

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I glMGP enannan Radiation Monitoring System RMS Protocol Technical Specircations p '6 1.3. Definitions, Acronyms and Abbreviations ANSI American National Standards Institute CM Measurement board CRC Cyclic Redundancy Code lEEE Institute of Electn' cal and Electronics Engineers LAN Local Area Network LDU LocalDisplay Unit LPU LocalProcessing Unit LSB Least Significant bit.

MASS Maintenance And Setup Software MSB Most Significant Bit NU Not Used PC PersonalComputer(IBM compatible)

RDU Remote Display Unit RMS Radiation Monitoring System SCADA Scan, Control, Alarm and Data Acquisition computers 1.4. References (1) ANSillEEE Std 729-1983 IEEE Standard Glossary of Software Engineering Terminology.

(2) MGP-SOAP - 45203 RMS Software Quality Assurance Plan (3) MGP-SDP - 45202 RMS Software Development Plan (4) MGP-GRS - 45254 RMS General Requirements Specification (5) MGP-SSRS - 45179 System Software Requirements Specification (6) MGP-LPU-SRS - 45180 Common LPU Software Requirements Specification (7) MGP-DU-SRS - 45182 DU Software Requirements Spc:ification 1.5. Overview This document describes the embedded communication interface for the RMS project. It does not concem communication board options.

We will first present the protocol principle, then describe implemented function in detail, and give information about communication lines supported by this protocol.

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i glMGP annunnes Radiation Monitoring System RMS Protocol Technical Specifications p7

2. Protocol definition 2.1. Introduction All the RMS devices have several digital communication links. The communication.

protocolis MODBUS/JBUS.

The protocol has to be compatible with JBUS (as defined by APRIL) and with MODBUS (as defined by MODICON).

MODBUS protocol allows communications between a master station and up to 255 slave stations, using point-to-point or multidrop connections. There is only one station, the master, that is allowed to start an exchange. Each station must have a specific address on the network (slave identification).

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gdinanuurunMGP Radiation Monitoring System RMS Protocol Technical Specircations p8 Each slave unit has an internal memory, called network parameter table, that is shared by the processing unit, and by the network driver, l '

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The protocol includes the following communication functions:

Function Description number 3,4 Read N words from the slave memory.

6 Write 1 word in the slave memory.

16 Write N words in the slave memory.

8 Communication diagnosis function (code 10 to 18).

11 Event counter reading.

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3lannuenMGP Radiation Monitoring System RMS Protocol Technical Specifications p9 It accepts the writing diffusion capability: Possibility to write the same data to all the slaves at one time by using the address 0. There is, in this case, no response from slaves.

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i 3 MGP penunens RMS Protocol Technbal Specifcations Radiation Monitoring System p 10 2.2. Exchange characterization An exchange is composed of two inessages:

. A request from the master

. A response from the slave Each message has the same frame (4 types of data):

slave ID Function Data area CRC 16 (control) 1 byte 1 byte 2 bytes

1. Slave ID (1 byte)

This slave number identifies the destination (1 to 255). If the number is zero, the request concems all slaves, there is no response.

2. Function code (1 byte)

To select the command (reading, writing...) and to check if response is correct.

3. Data area in bytes)

This information area contains function related parameters: word address, word value, number of words.

4. Control word (2 bytes)

Used to detect transmission errors. See annex 1 for CRC 16 calculation.

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3 MGP agnmaan Radiation Monnoring System RMS Protocol Technical Specifcations p 11 2.3. Timing characterization 2.3.1. Exchange synchronization:

. If a character is received after a silence of more than 3 charac'ers, it is cons!dered as a frame start.

There must be a silence on the line of minimum 3 characters between two frames.

Each unit when receiving a message has to:

1. Read the query message.

2, Ensure that the request is addressed to the unit.

3. Check the message integrity (CRC 16).

4. Check if the request is valid (good function number...).

5. Execute the action associated with the request.

6. Elaborate an answer.

7. Send the answer.

Everything has to be done within 30 ms to minimize the response time.

To detect the end of frame, the unit measures the time between every character we receive: If there is a silence of more than 3 characters, we consider that the message is ready. Here is the table of end of frame time-out according to the transmission speed.

Speed (BPS) 9600 19200 28800 38400 57600 115200 Time-out (ms) 4 3 3 3 3 3 For the diffusion command, we have to wait 50 ms before sending another message.

This delay allows the slave unit to end its frame treatment without being disturbing by a new frame.

1. Note. The minimum speed on the network is 9600 baud (for minimum communication efficiency), the speed by default is 19200 (acceptable on every unit or computer). The maximum speed on the line,115 kBauds (RS485 specification) is not acceptable on every unit because it depends on the capability the unit has to process communication frames. On RMS, LDU and DU units are limited to 57600 baud.

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l 34 avnuanesMGP Radiation Monitoring System RMS Protocol Technical Spedications p 12 2.3.2. Network load analysis Response analysis and next exchange

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MGP annunnes RMS Protocol Technical Specifcations Radiation Monitodng System p 13 2.3.3. Maximum exchange duration if previous conditions are respected, here is the slowest exchange: write 123 words at 9600 baud, Request frame length = 9+246=255 Response frame length = 8 At 9600 baud we consider that it takes 1ms to transmit one character.

Exchange duration =

255 (request) + 30 (treatment) + 8 (response) + 30 (treatment) = 330 ms The command time-out, maximum duration between the end of request transmission, and the beginning of the response reception, has to be in all case higher than the maximum exchange duration, i

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2.4. Request and response frame presentation Request aseodated data word addrus, word venues.

word number 1 byte 1 byte 2 bytes A A A r v 3 ,, r- 3 Functon Request:

($$) Data Control wo'd y

TNs code to select eveilebte commends When eleve r Mleives tie, it checks ins word and accepts or refuses the message The proSIhas 6 functions:

Function 3 and 4: Multiple word reading

-Function 6: Word writing Function 8: Communication diagnosis

- Function i1: Event counter reading Function 16: Multiple word writing 4,

Reed word values written word values Number of words

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g,lMGPannunum Radiation Monitoring System RMS Protocol Technical Specifations p 15 2.5. Slave received message control 2.5.1 Message control process When the master sends a request with following information:

. slave number (identification),

. function code,

. function parameters.

It calculates and sends the control word (CRC 16).

When a slave receives the request message, it stores it in memory, calculates the CRC 16 and compares it to the received control word. ,

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if received message is not correct (CRC 16s ars not equal) the slave does not respond.

If received message is correct, but the slave cannot treat it (bad address, data...), it sends back an exception message.

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3 MGP annumeng RMS Protocol Technical Specifcations Radiation Monitoring System p i6 2.5.2. Exception message content Exception code

1. Unknown function code (or bad diagnosis counter designation)

2. Bad address (>5000 on a writing request)

3. Bad data (bad number of words to read)

Received function 4. Unit not ready code wm nest 8. Writting failure (unused)

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1 Controlword L A A A >

Y Y Y Y 1 byte 1 byte i byte 2 bytes

& Example: Try to send an unknown function (# 9)

Request 1 9 0 0 0 0 CRC 16

Response

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gkannueensMGP Radiation Monitoring System RMS Protocol Technical Specifications p 17 2.6. Data representation The protocol manipulates 8 bit characters (coding from 0 to 255) on the line, but information that is to be sent or received is 16 bit word size.

2.6.1. Byte (or character) representation MSB LSB bR bR bR bR bR bR bR bR 7 6 5 4 3 2 1 0 B bits 2.6.2. Word representation MSB Most signircant Byte Least signmcant 6,t* LSB A A e v ,

bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 W J W

The mor,t significant byte is sent first on the line, then the least significant byte.

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3. Protocol functions 3.1. Multiple word reading: function 3 or 4 The number of words to read must be lower or equal to 125.

. Function 3: Read intemalwords.

. Function 4: Read extemalinput words, in fact, these two functions are Completely similar. It is then possible to use either one without any Change. There are both implemented for MODBUS/JBUS Compatibility purpose.

Request:

Slave ID 3 or 4 First word address Number of words CRC 16 L A A A A >

1 yte 1 yte 2 es 2 es 2hs

Response

N of Slave ID 3 or 4 ., F rst word value .. Last word value CRC 16 1[yte 1 e 1 byte ,, 2 bhes  ::[ytes 2 bhes t

h Example: Read words 805 to 80A from slave #2 Request 2 3 0805 6 CRC 16

Response

2 3 oC xxxx " ~ ~ ~ 1.' ' " ' YYYY CRC 16 Word 8 5 value word 80A value

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RMS Protoco! Technical Specifcations p 19 _

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! 3.2, Word writing: function 6 This is the faster way to write one ward into slave memory. To write two or more adjacent words, it is better to use the function 16.

Request:

Steve lo 6 Word address Word value CRC 16 L A A- A A_. >

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Response

Steve to 6 Word address Word value CRC 16

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1- byte 1 byte 2 bytes 2 bytes 2 bytes Response is the request echo signaling that the word has been correctly written into slave memory.

1. Note: If slave ID is 00, all slaves execute the command without sending back any response.

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Response

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'MGP t aparang Radiatkus Monitodng System RM3 Protocol Technical Specmcations p 20 3.3. Diagnosis counter reading: function 8 Each slave manages some' diagnosis' or event counters. There are nine counters per slave. Each counter is a 16 bit word. These counters are updated when a frame is received and processed by the unit (the message is addressed to the unit) and if this is not counter reading requests (function 8 and 11).

Request / Response: -

-J Slave ID 8 Sub-function code Data CRC 16 L A A- A A >

1 byte 1 byte 2 bytes 2 es 2 es Command Sub- Data function code Diagnosis countertwset 10 0000

,- Read totalnumber of:

. Received frames without CRC error 11 XXXX

. Received frames with CRC error 12 XXXX On request frame,

. Exception responses 13 XXXX XXXX is set to 0000,

. Frames addressed to the unit (except 14 XXXX on response, XXXX i

broadcast) contains specified

. Received broadcasted requests 15 XXXX counter value

. Not used but implemented for compatibility 16 0000 (always set to 0000)

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. Unit not ready responses (unused) 17 0000

. Character not processed (unused) 18 0000

'& Example: Read number of frames received with CRC error from slave #9 Request 9 8 12 0000 CRO16

Response

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3 MGP annuums Radiation Monitoring System RMS Protocol Technical Specifications p 21 3.4. Event counter reading: function 11 Each unit (slave or master) has an event counter that is incremented each time it receives and processes correctly a mesaage (except for specific functions that read diagnosis counters: function 8 and 11).

A diffusion command also makes the counter running. If a slave sends an exception command, counter ,s not incremented.

t This counter allows, from the master, to know if the slave correctly processed the command (event counter incremented), or if the slave did not interpret the command (event counter unchanged).

By reading these different variables, it is possible to get a protocol diagnosis between master and slave.

. If master counter equal slave counter, command sent by the master has been correctly processed.

. If master counter equal slave counter plus one, commarid sent by the master has not been executed.

Request:

Slave ID 11 CRC 16 L A A >

1 byte 1he 2[ytes

Response

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Slave ID 11 0 CRC 16 L A A- _A A >

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S\\annonesMGP Radiation Monitoring System RMS Protocol Technical Spedrcations p 22 3.5. Multiple word writing: function 16 This function is useful to write complete data structures to slave memories, it is possible to write up to 123 words (246 bytes) at once.

1 byte Request:

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Number of Number of slave t 16 words to write bytes Words to write CRC 16 (1 <= X <= 123) (N)

A 2 L A J 1 byte 1 byte 2 bytes 2 bytes N bytes 2 bytes 2 <= N <= 246 Sw First word to Last word to write write Y Y 2 bytes 2 bytes

Response

slave ID 16 First written word sodress Number of written words CRC 16 L A A A A J Y Y Y Y Y 1 byte 1 byte 2 bytet* 2 bytes 2 bytes

1. Note: If slave ID is 00, all slaves execute the command without sending back any response.

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g MGP annnang Radiation Monitoring System RMS Protocol Technical Specifications p 23 h Example: Write following data at 800 in slave #1 (800) = 10 (801) = 100 (802) = 1000 (803) = 10000 R0 quest 1 16 800 4 8 10 100 1000 10000 CRC 16

Response

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RMS Protocol Technical Specifcations p 24 3, Communication settings The transmission speed y default is 38400 BPS.

The character format is:

1 start bit 8 data 'ait No pa,ity 1 or 2 stop bit The transmission speed is setup by software and must include the following speeds:

9600,19200,28900,38400 and 57600 BPS.

This protocol is half-duplex, and does not need any hardware or software control (CTR/RTS, XONIXOFF). This is a binary protocol that uses the full 8 bit character size (256 different possible states for one character). This is therefore not possible to communicate in ASCll mod t. .

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Radiation Monnoring System RMS Protocol Technical Specifications p 25

4. Hardware interface The physicalinterface has to conform with the RS485 or RS232C nonti,

• 4.1. RS485 Multidrop Ir a' rface l

The resident communication interface meets the RS 485 standard, The RS-485 standard accommodates the requirements on a balanced transmission line used in party-line circuit configuration. It permito Multidrop applications where multiple drivers and receivers share the same line in data transmission.

The transmission line which is intended to be 1200 twisted pair is terminated at both ends The drivers and receivers can be distributed between the temilnation resistors.

120 OHMS g ] 120 OHMS 680 OHMS A, 680 OHMS /b /6 XX V XX XX V V Master Slave Steve Transceiver Transceiver Transcoever The communication will operate properly in the presence of reasonable ground drops, withstand line contention situations and carry 32 drivers and receivers on the line, W C 7,.G ' 7 4 %7.f' f,. 7 0 "." ~ 5 1 ~ s.. 45866 BA

SLMGP,,lmanuarans Radiation Monitoring System RMS Protocol Technical Specirications p 26 Because this is a bus type network, there are some topology constraints to respect.

Here are some good and bad configurations:

1 Bus topology with right distances (good configuration)

, 1000 .

metres Terrninator Terminator 6,. 9.

2

• y ,

{v Master Slave 1 Slave 2

2. Distances are not respected, this had configuration looks Ilke a star topology.

. 1000 .

ermiAstor metres

Slave 1 Master

ll  : Slave 2 Terminator LT Tb"m%"1707M",.OJE~m.,-som, 45866 BA

_ _ -- --- u

l 3bannuanesMGP Radiation Monitoring System RMS Protocol Technical Specifications p 27

3. Bus topology with right distances, but too many slaves (maximum of 32 stations on the same wire) 1000 metres Terminator Terminator A

h yA il .

n A v v v 3 Master,/' Slave 1 Slave 2 "-

Slave %Qiave 34 '

Y

[ h

& This is not possible to put more than one master on the same network 1000 metres Terminator Terminator a n -

A 1.

r_ v 3 Y

Master 17 '10 faster 2 SlaveDQve 2 J

h"CEb" ~w 1""M 1 7 0 7non / O ~n.nm 70 ~6 ono.s-. 45866 BA

JykMGP anmneun .,

Radiation Moni.n ing System RMS Pgtocol Technical Specifications p 28 4.2. RS232 point to point interface Serial Cable to connect a PC with_a D.U_125 to 9) l l

Computer Cable Display Unit 7..........., a......................................., e..........,

l DB25 Male l ! D825 Female DB9 Mak l '. DD9 Female l l

. 1 l..l 1 1 ll l

i l 14  ! 14 Trn Trn 2 ll

{ f; prn X Rrn . 3  !

l ll  ; l l ll 8 l l l l -

ll l l

l

.-- l, .l l l ll '

l ',

l ll l l l l l! .

l l l l ll ll l l 2s l l 2s l l l l

13 .l .l ts l, ,l l DB9 EIA Description DIN DB23 pins designation Designation pins 1 DCD Data Carrier Detect M5 8 2 RD Transmitted Daia D1 .

3 3 TD Received Data D2 2 4 DTR Data Terminal Rea'dy _

S1.2 20 GND 5 Signal Ground E2 7 6 DSR Data set Ready M1 6 7 RTS Request To Send S2 4 8 CTS Clear To Send M2 5 9 Rl Ring Indicator M3 22 1

h*A"""""M'O " "" M'O',~.',"L*",.*.,'0~.3 1 % e !45866 BA l

1

$,IMGP nmanans Radiation Monitoring System RMS Protocol Tednical Specifications p 29 Appendix A: CRC 16 algorithm BEGIN v

ir CRC 10 = FFFFh 1r CRC 10 = BYTE sor CRC 16 ir na0 1r RQht shMt CRC 10 la lheft a Carry CRCf C f 6 zor Yes4 2-n o rht e No Yes. , Next byte No _

/ Endof frame t Yes n = Data number of bytes EIvo POLY 16- 1010 0000 0000 0001 = A00th #

e Note: For CRC 16 word, the first byte that is sent is the least significant one,

& Example: Write 810h at 1000h in slave 1 Request frame O1h 06h 00h 10h 10h 00h 87h AFh L A A A J he der Ad ss Va$ue CR 16 3.* C L i b " = = M 1 7 O E 4".8EO..  % 45866 BA 7 ,

,d

2m .- - _ _ _ _ _ - . _ _ . . _