Description of the Communication Protocol
Contents
1. Acquisition i E Norma 0x16 is the scaling of the pressure output stored 2 729ms 5 5 00MSa s 3 48 ms Chanel 0x13 and 0x14 contain Pmin here Obar Ec AC I iH 10 0 1 id 0x15 and 0x16 contain Pmax here 3bar The table does not show the last action on the bus 10ms after the OxAC command follows the readout of the 5 data bytes in cluding STATUS pressure and temperature 1 1 LH KO ONH 9 H ee The graph shows a too long conversion time Display Scroll Zoom to 5 IC Lister Selection Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 11 24 It is possible to read out a unique product code the date of calibration and the scaling of the transmitter 5 Optional further Commands 5 1 Memory Map of User Information 16 bit memory cells Ld Den Wn 770 000 Ami 0x12 scaling Year 0 31 2010 Bit11 15 Month 0 15 Bit7 10 Day 0 31 Y bbit M 4bit D 5bit P 2bit Bit2 6 P Mode 0 3 Bit0 1 P 16384 f32 IEEE 754 single LSWord P_49152 132 IEEE 754 single MSWord Pmax bar als 32bit float P_49152 f32 IEEE 754 single LSWord IEEE 754 single respectively float from single precision binary floating point format P Mode 0 3 O PR 1 PA 2 PAA 3 AUX The combination of Cust_IDO and Cust_ID1 makes a 32bit code to recover calibration data at KELLER or to h2. Description of the Communication Protocol for Series 4 LD 9LD OEM pressure transmitter from KELLER Version 2 3 KELLER AG f r Druckmesstechnik Version 2 3 hof 03 Mar 2014 Lie se oo ee ne ee ee ee 3 2 liter gle MEDIE EE EDENDI 3 ME POOU esse 3 22 ANP PSI SONS ee een 4 758 0 e ne ee ee mnt EE E ee 4 24 Bus 6721072 0 a reer EEE rere mere EUR HE EUR rer eee eee CE EEE rence reece eee etree eee ee eee ee ere eee een eer 5 3 DCFG ee ee ee rs 6 gt STARTE NOMEN sad ccna asics ents gun snuesn TOONA AOOO 6 ae ADDRES I ee EEE E E E E E EE EEE E A E E 6 3 9 ACKO T A T II DATA ee a E ae ee ee ee eee eee 7 4 Get Measurement Data niit hie nit iin 8 41 Gerihedigital Valde S nennen ee een 8 4 2 Interpretation of the digital Valle ss deci REN eer er ete rier ee nee ma NM ea een 8 4 3 Variants to detect the End OT Conversion ae ae 10 24 olage Time DIAdraliS eee eae a a a 11 Sy 3Obp bhalflfther Comimallds sosta EA a ee 12 94 Memory Map of User Information ann aan 12 5 2 Recommended Slave Addresses ccceccssssssssssssessssessssesescsecsssecsssaesesaesesausessesecsesaesesausesausesacsessesacsesausesansesaesesaesasensas 14 5 9 hanging he Slave Addresse 15 MB CU Sic Manual nennen rennen 16 6 1 USB C Dongle 16 6 2 PC Application to change the Slave Address sess nnne tn nnn nnn intenta innt 18 L ADENO ome
3. TFC floor T u16 16 24 x 0 05 C 50 C T u16 gt gt 4 24 x 0 05 C 50 C Reduce the 16 bits of the temperature information first to 12bit the last 4 bits are anyway noise floor This way a resolution of 1 20 C is still given Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 8 24 Examples Read Measurement after a request by 0x80 OxAC and waiting for gt 6 5ms ADDR 0x40 Read STATUS Pressure Temperature STATUS 0x40 means no error just powered Pressure Ox4E20 20 000dec for a PR 7LD 1 10bar transmitter p bar 20 000 16384 x 10bar 1bar 32768 1bar 0 213867 bar for a PA 4LD 30bar transmitter p bar 20 000 16384 x 30bar Obar 32768 Obar p bar 20 000 16384 x 30bar 32768 3 31055 bar 4 31055 bar in relation to vacuum for a PAA 9LD 3bar transmitter p bar 20 000 16384 x 3bar Obar 32768 Obar p bar 20 000 16384 x 3bar 32768 0 331055 bar in relation to vacuum Temperature 0x5DD1 24 0173e T C 24 017 384 x 0 003125 C 50 C 23 8531 C incl noise Shift right by 4 24 017 16 1501 T C 1501 24 x 0 05 C 50 C 23 85 C without 4 Bit of noise Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 9 24 4 3 Variants to detect the End Of Conversion Yellow SCL Blue SDA Red EOC Green SUP
4. 3 hof 03 Mar 2014 Page 5 24 3 Data Frame 3 1 START and STOP Condition u e u Every data frame is bordered by a start and a stop condition The START bit S is caused by pulling down SDA while SCL stays high Then SCL has to go low before the first data bit is set SCL is than ready for a positive edge when the data line is valid to trigger the receiver After the last transferred data bit the SCL line goes high and the STOP bit P is sent by releasing SDA while SCL is constantly high 3 2 ADDRessing The first Byte of every data frame contains the slave address and R W bit ADDR R W The 7 bits allow 112 bus nodes 16 of the 128 possible addresses are reserved 0x00 0x07 and 0x78 Ox7F The default slave address of the D Line transmitters is 0x40 D Line transmitters answer only to the address stored in the memory There is no response to the general call address 0x00 Examples ADDR is 0x43 For a data transfer from the master to the slave write the first byte is 0x86 ADDR is 0x47 For a data transfer from the slave to the master read the first byte is Ox8F Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 6 24 After every transferred byte in both directions the receiver of the byte gives feedback with the acknowledge bit 3 3 ACKnowledge The slave should always confirm the bytes by an ACK A If the slave does not respond with a LOW lev
5. 400 kbit s Fast Mode Plus 1 Mbit s High Speed Mode 3 4 Mbit s It is recommended to start with a low speed e g 50kHz get the whole thing working and then increase the bit rate if needed The maximal possible speed depends also on the cable length capacity and the pull up resistors Because the I2C interface is a synchronous serial bus the bit rate doesn t have to be stable The master defines the timing That makes bit banging easy if there is no dedicated hardware integrated in the master controller Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 4 24 2 4 Bus Capability E SigCond igCond h h 1 ker e VSS The bus capability is given by the physical electrical and the data link protocol bus layer On the electrical layer are only active LOW signal levels allowed This avoids short circuit currents caused by a collision of a HIGH and a LOW level and makes clock stretching possible On the protocol layer addressing is needed Therefore every slave on the same bus has to respond on a different address The address is stored in the memory of the transmitter The additional EOC lines undrawn which signalise the End Of Conversion can not be coupled together without an AND gate But there are solutions without using the EOC line or all the EOC lines can be routed independently to a parallel port of the mas ter microcontroller Communication Protocol 4 LD 9 LD Version 2
6. DelaylOTCYx 125 IZC read xByte ADDR 3 tci U32 25S5Cget lL izes Pmax cast floatingpoint ff O 4dus x 10 x lz5 O Sms ff O dus x 10 x lz5 O Sms Cast twotimesU1l C t U32 2SSCget Z 11 SFr 7 request new conversion Sfr Af Ll2C write lLByte ADDR Oxal j return Ox31 Yee ee wait for new conversion result Sr DelaylOOTCYx 250 X OQ dus x 100 x 250 l ms f f read the results our Sfr ifiI2C read xEyteiAbDER S return 0r91 fff Interpret integer values yrl al status Zl pressure SS get U Ole 2S5cget Z i 16 Z 5Cget 4 i F32 FE I tf UlsE 2SSCget l 3 lt 8 tt 016 2Z8S8Cqet 3 11248 al temperature al pressure al pressure l156224i1 iPmax Pmin 227525TPmin Zl temperature f t Ulei4l temperature gt 4 24 0_ 05 50 return 255Cerror end of US get PnT GPIO US ADDERE Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Ut US2 izSS5Cget z2 31 z16 iri O32 zSSCget z s216 Ve Le ff ff p Uls5 ff T U16 US Jr p bar ff TI E Page 23 24 7 2 Application Notes Coming as soon as possible 7 3 Protocol Changes e Document Version 2 0 7 December 2012 Many chapters with basic information to the I2C interface added the Version 1 0 was a preliminary version with only KELLER specific descriptions Changed the default Slave Address from 0x00 to 0x40 e Document
7. Version 2 1 15 February 2013 Changed the Conversion Time from 10ms to 4ms New Graphics to show the faster sampling and the lower shorter cur rent consumption e Document Version 2 2 05 November 2013 Mainly the chapter K 404 User Manual added Further slight revisions for a better understanding but no technical changes e Document Version 2 3 03 March 2014 Changed the Conversion Time from 4ms to 6 5ms 6 5m is the worst case including variation over the whole temperature range of 40 110 C and all manufacturing tolerances 7 4 Firmware Versions The Firmware is fixed in the Silicon ROM Version and can t be changed by KELLER A few settings and the content definition of the Customer Memory are the only free parameters but there are no plans to change anything Version Date of Major Changes Year Week Production 36Cl1CH since Base Version with temperature PGA settings for 40 110 C 12 29 2012 36Cl1CK since Base Version with temperature PGA settings for 40 110 C 14 13 April 2014 and temperature sensor settings for lower pressure dependency 7 5 Support We are pleased to offer you support in implementing the protocol Use our free PC software D Line Address Manager in combi nation with the K 404 USB to I2C Dongle for a first communication with the transmitter and for the configuration of non default Slave Addresses Please visit our website http www keller druck com to check updates and furth
8. additional wire per transmitter is aan needed It is not possible to connect all the EOC VX agas Wires commonly like SCL and SDA of the bus sys r tem B Cursors m Mode Source 45 Cursors Units X1 280 000000us Y1 56 77500V Manual EOC BN X2 y 1X2 3 760000000ms Y2 6 775000 DSO X 30144 MY52011071 Fri Feb 15 11 00 06 2013 gs NUNG 1 100v 2 100v 3 100V 4 1 00V 0 0s 1 0003 Stop 1 33V To save me without the additional EOC wire IS pos 2 Agilent sible by reading out the status of the pressure trans Acquisition mitter There is no request needed just a simple Normal 50 0MSa s readout command for the first byte that contains the a u e TIENDA DC BW 10 0 1 3 800000000ms n MIU nates Busy will be 1 d th LE TAX on itn erde he TT m EIN RD a E to 0 Then the new data is ready to read out by ad loaded ditional Clocks for the pressure and temperature o B00 podeedeodooda bytes or a new readout command to shift out the Mode Source 49 Cursors Units X1 280 000000us Y1 5 77500V Manual aon mid nam yz e77zs0v_ Whole 5 byte data frame Cursors This variant effects the highest power consumption because the Master controller is nonstop busy and also the pull up resistors are en
9. the slave follows immediately to the EOC line or to poll the STATUS byte negative edge of the 8th clock impulse two times visible DSO 30144 MYS201 1071 Fri Jul 20 08 40 25 2012 DS0 30144 MY52011071 Fri Jul 20 08 43 56 2012 50 005 Stop t d 2 00V 1 an 2 200V 3 4 200V 11 848 100 03 Stop 200 2 200W 3 si m E sie Agil t Annan ognan 1 ater o l 8 Acquisition er JL era 1 006Sa s FR Channels E arii 1 B j T 10 0 1 Li 10 0 1 IC 10 0 1 em pep 10 0 1 DRA n AALA AD AI D Mu l M 114 500000us T TIT TI TLI s 8 7336kHz 1 O0 tf llildll gl 3 55000V pt if bum More detailed view of the readout frame EOC is back to 3 6V re a Host e The slave ACK occurs as normal immediately after the neg No acknowledge NACK from the master after reading out the edge of the 8 clock impulse The ACK from the master occurs 5th data byte The Missing Ack that is recorded in the tables is with a little delay but this is allowed because the master gener not a mistake it s a must ates the 9 clock impulse by itself at the right time DSO X 30144 MYS2011071 Fri Jul 20 08 45 13 2012 pow 2 20w 4 20 os 2 sop 2 2m On the left side are 4 read cycles on the memory visible before Ack et E 5 Agilent the request OXAC command occurs In the memory cells 0x13 jus
10. the wires or a flexible printed circuit FPC depending on the cross section because the cur rent consumption is very low Sleep Mode typ 100nA Active Mode typ 1 5mA during conversion in less than 6 5ms typ 5ms Be careful with cabling over more than a few centimetres The I2C Bus is not a fieldbus and only EMC safe if the interconnections are short or screened by the surrounding housing of the whole application or a suitable cable Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 3 24 2 2 Pull up Resistors VDD SUP SCL SDA Pf l1 HiZ HiZ HiZ HiZ IN IN IN IN u u EN Pull up resistors are needed at SDA and SCL 1 10kOhm are recommended In order to optimise the data rate or low power consumption other resistance values are possible The EOC Pin supplies an active high level in idle state and an active low level during conversion The SCL and the SDA lines are open drain driven The wired AND circuits avoid level collisions Additional series resistors placed directly at the bus members leads to even more security An electric HIGH level stands for 1 a LOW level for 0 gt positive Logic Please be careful with non open drain hardware like general purpose lOs and tri state tricks 2 3 Bit Rate The D Line transmitters work over a wide range of data transfer speeds All four modes are supported because the maximum clock frequency is 3 4MHz Standard Mode 100 kbit s Fast Mode
11. to use KELLER s USB to I2C converter and the related PC Software 6 K 404 User Manual 6 1 USB to I2C Dongle The K 404 T is equipped with a plug to connect directly to the 5pol TO header The 9LD on the TO plug is not part of the converter The cable on the I2C side is less than 30cm one foot long For EMC reason please extend the connection on the USB side if needed The K 404 converter is short circuit protected The EOC Pin is not connected and SDA and SCL are pulled up to the 3 3V supply by internal resistors Please be careful by connection an oscilloscope with relation to earth because there is no galvanic isolation built in the converter Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 16 24 Connect the dongle first to the computer and wait until the operating system has installed the driver before you start the related application This runs automatically You will find the converter than under Control Panel Devices and Printers as IO Warrior56 IO Warrior56 Modell IO Warrior56 i Kategorie Eingabegerat It is a standard Human Interface Device therefore you don t have to install a specific driver TUI RN Allgemein Hardware li IO Wamior56 Gerateinformationen Hersteller Nicht verf gbar Modell IO Warrior56 Modellnummer Nicht verf gbar Kategorien Eingabegerat Beschreibung Nicht verf gbar Gerateaufgaben Klicken Sie unter Ger te und
12. 0 00 15 000 23 08 2013 12 28 21 The important information and the key function Change Device Address are displayed on the left skyscraper frame the rest of the surface is bonus material Please select as first step your language in the pull down menu Options under Settings Options The application remains your Style Language and Logfile selection Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 18 24 The D Line Address Manager does scan the I2C bus by checking the response acknowledge to every possible Slave Address from 0x00 to Ox7F After finding a working transmitter the User Information see chapter 5 1 is read out and displayed in de coded form The most important information is the pressure range to new the scaling of the 32768 output range Main functions Device Information Pressure bar Temperature C Scaling 0 000 3 000 PAA PR Vented Gauge Zero Atm PA Sealed Gauge Zero 1bar PAA Absolute Vacuum i At the same time the actual measurement results are E shown in the Monitor frame converted to bar and C Unique ID FOO222E0 1P0005 Device Status Normal Mode Slave Address Pfu 16 T u16 26906 24741 The unsigned 16 bit values who are really transferred on the bus are also always refreshed New Slave Address Number of Re Addressing left Do you wish to continue with assigning new slave address 0
13. Bit Rate 75kHz DSO X 30144 MY52011071 Fri Feb 15 10 57 09 2013 amp een OH So 133 The simplest way to detect the end of a conversion tote or 2 Agilent EOC is to wait until the new data is definitely ready Acquisition to read out Being on the safe side the conversion I 1 0 NN A I d NN ON MN 30 0MSa s and the conditioning of the Er and tempera illc EEE EN r Uem ture value is completed after 6 5ms vo While the gt 6 5ms of waiting the Master controller uw can be in sleep mode or doing some other tasks like Cursors hemmen requesting other pressure transmitters on the bus to 1 AX NN make a new conversion Ayla 0 0v The graph shows a too short conversion time Cursors _ Mode Source Cursors Units X1 280 000000us 1 6 77500 Manual EOC A X2 v J x2 5 280000000ms 2 6 77500V DS0 X 30144 MY52011071 Fri Feb 15 10 54 07 2013 E 100V 2 100V 3 100V 4 100V D 100 Cga 1 133V The handshake solution done by the additional Agilent EOC wire is very elegant and is suitable to save Acquisition time and power The Master controller can be in Normal 25 0MSa s sleep mode and will be awoken by an external inter Channels rupt on the positive slope of the EOC pin Polling the ee DG BW 10 0 1 wsw 1001 level of the EOC wire is also possible DC BW 10 0 1 jew 0 For this solution an
14. Drucker mit der rechten Maustaste auf das Symbol f r das Gerat um Aufgaben f r dieses Gerat anzuzeigen Communication Protocol 4 LD 9 LD Hardware au IO Wamior56 Ger tefunktionen Name Typ 3 HID konformes Ger t Eingabeger te Human Interface Devices 5 HID konformes Ger t Eingabeger te Human Interface Devices 3 USB Eingabegerat Eingabeger te Human Interface Devices 3 USB Eingabegerat Eingabeger te Human Interface Devices USB Verbundger amp USB Controller Geratefunktionszusammenfassung Hersteller Standard USB Hostcontroller Ort Pfad 0 Port_ 0002 Hub_ 0005 Geratestatus Das Gerat funktioniert einwandfrei Version 2 3 hof 03 Mar 2014 Page 17 24 6 2 PC Application to change the Slave Address First install the latest D Line Address Manager application on your computer You find it on the software CD coming with the K 404 converter or it can be downloaded free of charge at www keller druck com The D Line Address Manager is a one button application It s important to connect the USB to I2C converter first to the PC and start the application afterwards It begins autonomous to scan the I2C bus and shows the values of the found D Line trans mitter without any click Hot plugging of the transmitter is possible E KELLER D Line IIC Slave Address Manager Version 1 0 3 4 125 100 75 50 25 0 25 50 00 00 10 000 0
15. ZC ff Array to for pressure value in bar as single IEEE 754 for temperature value in C as single IEEE 754 for 5 bit status receive data frame BPR PERRIER EGG DRE EG PB Ee Ff if prototypes global functions H8 get Put GPIO US _US get Put MSSP US Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 22 24 7 1 2 Read Measurement C File STE ee eee ee ee ee ee ER ET EFT ee ae ee ee ee ee ELF FEE global functions I8 get Put GPIO US ADDR US zS5SCerror _F32 Pmin Pmax union _F3z floatingpoint _US2 twotimesUl6 cast FF init Ius Pe fief better once before while li SDA OD 0 ff LOW if output active Open Drain SCL Ob 0 if LOW if output active Open Drain ba OUT 1l release SDA gt pull up resistor makes HIGH level SCL DUT 1 release SCL gt pull up resistor makes HIGH level ff read the scaling Sfr T2C write lByte ADDR 0x13 Delayl TCYxilzs5j IZC read xByte ADDER 3 cast twotimesUle iii H3z iz5S5C0get lli i csz4 IZC write lByte ADDR Oxl4 DelaylOTCYx 1253 IZC read xByte ADDER 3 cast twotimesUl amp e iii Use 26oCget 1l is lt e Pmin cast floatingpoint ff O 4us x 10 x 125 O Sms ff O 4us x 10 x 125 O Sms it U32 288Cget Z IZC write lByte ADDR Oxl5 DelaylOTCYx 125 IZC read xByte ADDR 3 cast twotimezUl ff Use e46eCget l lt 44 IzC_ write 1lByte ADDER 0x161
16. ave a recognition feature for data bases on the customer side The scaling e g PR 1 10bar is stored in ScalingO to Scaling4 but could also be read on the associating papers The date of calibration is an additional information that finds also place in Scaling0 Read Memory Content ADDR default 0x40 First byte is ADDR lt lt 1 1 for Read ADDR lt lt 1 0 for Write 1 Request Measurement 2 bytes from Master ADDR W MTP Address 0x00 0x16 2 Wait for 0 5ms or check the Busy flag 3 Read Measurement 1 byte from Master 3 bytes from Slave ADDR IR STATUS Mem MSB Mem LSB Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 12 24 In the two LSBs of cell 0x12 is the pressure mode sealed or vented gauge and zero definition stored 4 Interpretation The content of cell 0x13 and 0x14 is a floating point value that indicates the pressure in bar for the lower output value 16384 The content of cell 0x15 and 0x16 is a floating point value that indicates the pressure in bar for the higher output value 49152 Example Scaling OxBF80 binary to float OXBF800000 1 0E0 Scaling2 0x0000 1 bar Scaling3 0x4120 binary to float 0x41200000 1 0E1 Scaling4 0x0000 10 bar Unique Product Code Cust_ID1 x 65536 Cust_IDO 0x01110415 17892373 Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 13 24 If you want to combine more t
17. el after the 8 bit the master detects an exception for example caused by requesting to the wrong slave address A NACK N form the master s side is not always an exception It is also needed to terminate a read data frame I2C Write W ADDR oa COMMAND ap 2C Read R ADDR STATUS P MSB P LSB Ne Underlined bits and bytes come from the slave the rest comes from the master 34 STATUS Byte pe ES Ea pem e Busy 0 conversion completed 1 busy Mode 00 Normal Mode 01 Command Mode 1X Reserved Memory error 0 checksum okay 1 error 3 5 DATA Bytes The data registers of the D line transmitters are always 16 bit long Before the data bytes stands always a STATUS byte Therefore are three possibilities to read out data useful one three or five bytes By reading one byte you just get the STATUS of the D Line transmitter Reading three bytes is useful to get STATUS and the pressure information u16 or a 16 bit register from the memory Reading two additional bytes five bytes over all is useful to get both 16 bit measurement information pressure and tempera ture The master has to terminate a read data frame with a NACK and the obligatory STOP bit independent from the count of read bytes Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 1 24 4 Get Measurement Data Underlined bits and bytes come from the slave the rest comes from the master 4 1 Get the digital Value
18. er application notes KELLER AG fur Druckmesstechnik St Gallerstrasse 119 CH 8404 Winterthur Tel 441 52 235 25 25 http www keller druck com Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 24 24
19. erase already burned 1s is not possible in a OTP ADDR 1 0 0x02 wait 0 5ms ADDR lt lt 1 1 Status HighByte LowByte The Slave ADDR is in the 7 LSBs All other 9 bits should be 0 In the Status Byte appears an additional 1 to indicate the Command Mode Bit3 1 Bit4 0 4 Setnew Slave Address in memory cell 0x02 with the write command offset of 0x40 ADDR lt lt 1 0 0x42 HighByte LowByte The Slave ADDR is in the 7 LSBs All other 9 bits should be 0 5 Optionally check verify the new memory content by repeating step 3 6 Update the Slave Address in the RAM in the transmitter by switching the power off and on sending the Start NOM command 0xA8 does not update the RAM Communicate from this moment on with the new Slave Address Note Because it is not possible to update the CheckSum over the whole memory content the Memory error flag in the Status Byte is from now set Bit2 1 If you want to integrate the address management into you own software environment please ask the KELLER development de partment for more information about the internals of the D Line Copying the whole memory content to the next page is a difficult sequence One little mistake makes the transmitter unusable Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 15 24 The easiest way to change the slave address of a D Line transmitter or to check the scaling and other product information is
20. ergized more often Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 10 24 The following measurements are taken with 1kOhm pull up resistors In series to the master controller SCL and SDA line are 100E resistors to get a visual difference between an active LOW level from the master and from the slave The slave is able to pull SDA hard to ground a LOW level from the master goes only down to 10 of the supply voltage The address of the slave is 0x00 and the bit rate 100kHz Yellow SCL Green SDA Red EOC Blue 12C analyser DSO X 30144 MY5201 1071 Fri du 20 08 36 48 2012 DSO X 30144 MY52011071 Fri Jul 20 08 38 p 2012 1 Ed CN LE 4 200V Os 200087 2 20V 3 1 zum 2 2 0097 3 2 00V us EE C S AGES Data FE Agil zl ea Agilent 11 82ms 40 3F 06 5D 70 f E Acquisition 3 I ee m 250MSa s INN es Ei Gee IE Channels E 1 xl ht Loc no AMT I um om NI a i CTT Data AC IC 10 0 1 Es a uuu L Cursors AG eel INFR 7 750000000ms 4 4 Voltage Time Diagrams 4128 03H Yi 3 07500V E 7 EEE EEE EEE v es EEE The EOC line is low for 7 75ms The newest datasheet guaran 4 tees a conversion time below 6 5ms To reach sample rates over Lp tr gt LL 130 SPS itis a must to work with a high bit rate and to check the Nice to see The ACK from
21. han one pressure transmitter on the same I2C bus the slave addresses have to be unique For this purpose the memory content of for example a second transmitter has to be overwritten It is not possible to erase the content to make any possible change because the memory is based on a one time programmable technology so it is only possible to add some 1 s by burning additional bit cells After adding 6 1 s to the 7 bit slave address register there is a further possibility to make changes clearing the whole memory content by incrementation of the page counter That gives you in minimum a second chance to choose a slave address absolutely independent from the tries before 5 2 Recommended Slave Addresses The conclusion is that it is not possible to change the slave address unlimited times So it is recommended to plan the whole bus system and program the bus addresses once or in case of something unpredictable a second time To have more than one possibility per memory page to change the slave address we recommend the following set off ad dresses a 1s Transmitter default 2rd Transmitter 0x41 mu 3rd Transmitter mc 4th Transmitter 2 3 5th Transmitter Ox4F 5 6th Transmitter 0x5F 6 7h Transmitter 0x7F With the mentioned addresses it is possible to make for example a 3rd transmitter on the bus to a 4t The 12C committee does not recommend to use addresses between 0x78 and Ox7F so the 6 try is possible but not favou
22. n 0 3335 Increment 0 0001 Reset Decimals 4 Show GridLines Left Axis Right Axis V Automatic E M Show GridLines Right Axis This functionality makes it possible to zoom in or out and change the scaling of the axis To make manual changes the check box Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 have to be deactivated and the entering of a new figure be confirmed with the Enter key not by just clicking to the next box Page 21 24 7 Appendix 7 1 Code Examples Still under construction 7 1 1 Read Measurement Header File fee eee eee ee eee eee ee ee ee eee eee eee eee eee ee ae ee if constants define SDA OUT fdefine SDA OF define SDA IN define SCL OUT define SCL D define cal Pmin fdefine cal Fmax TRBISDbitsz TRISD5 ff BOS is SDA without MSSP LATDbitsz LA TD5 PORTDbits PRD5 TRISPhbits TRISDE ff PDE is SCL without MSSF LAT bits LATDS 30 ff fix coded or read out from the uzerMEHM ff fix coded or read out from the uzerMEHM ISEFESIIZJXSNgFPIIJNSYJgPXZPJSNIJIPFRIIYINIYINJXGZJPPJIISJSgTEISXHIPPEISg PITIJJEEEJ 4 V global variables fifndef _ C ZI ZSSC extern fendif _F32 l pressure fifndef X C ZI ZSSC extern fendit F32 ZI temperature fifndef C ZI ZSSC extern eridi _Us l status fifndef C ZI ZSSC extern fendif _US z550get 3 IZC F Variable IZC i Variable IZC d Variable I
23. red The addresses 0x00 to 0x07 are also reserved and 0x00 is the General call address If you change the slave address and don t use a new memory page the checksum can not be updated The STATUS byte is then no longer 0x40 only bit 6 is set it becomes 0x44 Memory error appears but that has no effect to the functionality of the transmitter it just makes it impossible to detect a memory error Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 14 24 A free choice of the slave address is difficult to write this should only be done with the KELLER USB to I2C data converter in combination with the appending KELLER PC application When using the KELLER converter and KELLER software it becomes a simple easy to use procedure Please ask for details if you are not already aware of these products and consider the user manual in chapter 6 5 3 Changing the Slave Address KELLER do not recommend attempting to change the slave address with the following procedure but you can do it so we will give the details Using this method it is only possible to write additional 1 to the current memory page 1 Turn off the power supply of the transmitter 2 Setthe transmitter into Command Mode by sending 0xA9 as first command ADDR lt lt 1 0 0xA9 3 Optionally read the actual Slave Address from memory cell 0x02 also possible in Normal Mode to get the needed in formation to add only one single 1 to
24. s ADDR default 0x40 First byte is ADDR lt lt 1 1 for Read ADDR lt lt 1 0 for Write 1 Request Measurement 2 bytes from Master s 2 Wait gt 6 5ms or wait for EOC 1 goes up to VDD or check the Busy flag 5 in the status byte only 1 byte reading needed 3 Read Measurement 1 byte from Master 5 bytes from Slave ADDR IR STATUS P MSB P LSB T MSB T LSB Getting only the pressure information it is possible to read out only 3 bytes from the slave 4 2 Interpretation of the digital Values The scaling of the pressure and the temperature is a simple straight line function defined by two touples points This leads to the following linear equations P u16 16384 P 16384 resp P min e g 1 bar PR 4152 P 49152 resp P max e g 30 bar PR The pressure range of the transmitter is stored in its memory and or written on the associating papers P bar P u16 16384 x P 49152 P 16384 32768 P 16384 The output range is 74 to of the 16 bit output word This way a little over and under pressure is measurable and the exceeding resolution of more then 30 000 point guarantee a very high resolution of 10 000 points even for the next lower standard pressure range T u16 50 C The scaling goes from 50 to 150 C but the working temperature range of the transmitter is at maximum 40 110 C depending on the order 0 50 C and 10 80 C are the standard temperature ranges
25. s GREMIEN MEE EMEND MEE EMEND MEDIE 22 Ta ode Each heine nie 22 672 PAD OME AMO IN OUCS ee Tee 24 Po PEOC IN ANG EO A E AA A EE 24 A FON VER ORO 24 P O settee caps ee A E ee 24 Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 2 24 Visually the Series 4 LD 9 LD are like standard KELLER pressure transducers with a 5 pin interface to connect the half open Wheatstone Bridge But these 12C versions contain beside the pressure sensor a very tiny signal conditioner This results in an OEM pressure transmitter with a digital interface The D stands for digital and for dual the LD Line provides pressure and temperature information 1 Introduction The most important topics regarding the communication with the Series 4 LD 9 LD and KELLER s unique embedded DSP core are listed in this protocol description especially the interpretation of the readout values For more information about the 2C specification please visit the NXP website and have a look at the User Manual in the docu ments section 2C is a licence free standard since 2006 http www nxp com documents user manual UM10204 pdf 2 Electrical Interface 2 1 Pinout Lane oeserpon wie 1 8 3 6 V Connection GND I C Clock C Data End of Conv Notes Be careful with the glazed pins cracks in the glass pills causes leakage gt damage Do not touch the steel diaphragm Cabling There are no special requirements to
26. s and have to be connected to the cus tomer s microcontroller Bonus Material The two additional buttons and the slider for the sampling rate are the only important control elements for the monitor Click simply on Start and the graph begins to roll The scaling of the axis is set automatically to a reasonably range Fast Glow Start c Clear Chart Fast ca 30 SPS Slow 1 SPS The Pressure and the Temperature bars are synchronous updated The levels of the bars are displayed in figures in the Pressure bar and the Temperature C text box The captions show the over the I2C bus transferred unsigned 16 bit figures Pressure F PR f Dur ressure bar Temperature 3 000 2 600 2 200 1 800 Temperature C Pressure bar Temperature C Fuis mia wf 0 963 The scaling of a D Line transmitter is always in bar and C There are two ways to convert the figures to other units 1 Conversion of the conditioned figures for example from bar to psi 2 Conversion of the scaling endpoints and direct conditioning from u16 to e g psi It is very interesting to know the unsigned 16 bit figures for the conversion according to point 2 Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 20 24 By dragging the mouse over the left boundary of the graph the following menu appears Axis ChartColor Axis Color Lett Axis amp Left Axis V Automatic ax z 1 2111 Mi
27. x43 to device One change of slave address left Mew Slave Address 3 Change Device Address The reason to offer this communication tool is to make the changing of the slave address as easy as possible The memory tech nology of the D Line transmitters is one time programmable OTP There are 4 pages of one time programmable memory That means that it is a must to do the copy job right first time the D Line Address Manager can do all of that for you Please be careful with changing the address because with every change the number Re Addressing remaining will count down until there are no more address changes possible New LD Transmitters will normally be delivered with either 2 or 3 address changes remaining The change request has to be confirmed by the shown popup window that displays the chosen new address again After doing the change a further popup window appears It shows the whole memory content and can also be opened with the pull down menu Dongle under Show Memory Map The content is just to your information After closing it the Device Informa tion frame will be updated with the new salve address Communication Protocol 4 LD 9 LD Version 2 3 hof 03 Mar 2014 Page 19 24 The Monitor frame is only a simple tool to get a first impression of the transmitters output The USB Dongle and this graph func tion are not developed for in application use The D Line transmitters are OEM product
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