Campbell SDM-CAN, User Manual

Page 1: ...SDM CAN CAN Bus Interface User Guide Issued 26 6 07 Copyright 2001 2007 Campbell Scientific Ltd CSL 419...

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Page 3: ...lieu of all other guarantees expressed or implied including those of suitability and fitness for a particular purpose Campbell Scientific is not liable for consequential damage Please inform us before...

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Page 5: ...ced Programming Techniques 3 12 3 4 1 Interrupts Using the I O Connection 3 12 3 4 2 Group Trigger 3 14 3 5 Program Examples 3 14 3 5 1 Reading CAN Data 3 14 3 5 2 Simple CAN Data Transmission 3 15 3...

Page 6: ...N Data Frames and Data Encoding and Decoding D 1 Figures 1 1 SDM CAN CAN Bus Interface 1 1 2 1 SDM CAN Internal Jumpers 2 3 2 2 SDM CAN Isolation enabled 2 3 2 3 SDM CAN Isolation disabled 2 4 2 4 Usi...

Page 7: ...the standards to which a network claims to comply Campbell Scientific cannot provide full technical support in the understanding and decoding of data on all types of CAN networks Figure 1 1 SDM CAN CA...

Page 8: ...applications All configuration of the interface is specified within the user s datalogger program LED status flash at power up Additional I O port for signalling to the datalogger that data is availab...

Page 9: ...isolated CAN driver circuits by an external source the current drain by the SDM CAN is approximately 50 mA lower than the figures quoted above Typical active current non isolated with the CAN Bus in t...

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Page 11: ...set to match the commands in the datalogger program relevant to each interface The SDM address switch can be set to 1 of 16 addresses The factory set address is 00 Table 1 shows switch position and t...

Page 12: ...if a converter is not used power must be provided from elsewhere see below The default setting is for the converter to be OFF although for many applications you may need to turn it on once you have c...

Page 13: ...non isolated CAN Bus interface The jumper block can be removed and rotated so that the red bar is nearest to the mode arrow head The default is for isolation enabled The CAN Bus termination impedance...

Page 14: ...h allow access to the SDM function as well as retaining normal function of the serial port please contact your local sales office for further details The SDM CAN requires a nominal 12V power supply co...

Page 15: ...ground Where multiple SDM devices are in use connect them in parallel to datalogger SDM ports making sure each device has a unique SDM address Ensure that the maximum cable length between the datalogg...

Page 16: ...3 way screw terminal is marked as G H L on the SDM CAN case where G Ground H CAN High L CAN Low The CIA 9 pin D connector pin configuration is shown in Table 2 3 Table 2 3 CIA CAN Connector Pin Conne...

Page 17: ...ping into CAN networks and also recommend maximum lengths for T s or stubs off the network For instance at the highest baud rate of 1Mbit s ISO11898 recommends a maximum bus length of 40 m and a maxim...

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Page 19: ...se parameters otherwise either no data will be received or you risk corrupting data on the bus if the SDM CAN is enabled for transmission The next common function is to read data back from the SDM CAN...

Page 20: ...including the speed of the datalogger in question the program it is running how many SDM devices are in use and to a lesser degree other tasks it is running e g communications activity In practise for...

Page 21: ...ng built However if your program tries to send frames too quickly before earlier frames are sent the frames will be overwritten and lost This scenario generally does not happen with CR10X CR23X logger...

Page 22: ...etworks the relationship between some of these parameters is predefined and just one parameter the baud rate is quoted For maximum flexibility though the user is given access to all of the relevant pa...

Page 23: ...CAN samples the data bit and is known as tTSEG1 The final segment is known as phase segment two or tTSEG2 The relationship between these times is summarised by tbit tq tTSEG1 tTSEG2 tTSEG1 in seconds...

Page 24: ...st ID parameter parameter 05 sets bits 0 10 entered as a number between 0 and 2047 This parameter also determines whether an 11 bit or a 29 bit Identifier is set If you index this parameter then an 11...

Page 25: ...ich data is encoded or decoded Within a byte the MSBit is always first on the left Where the number of values parameter parameter 11 is greater than one the same function is applied to successive sect...

Page 26: ...Data type 13 Unsigned integer most significant byte 1st 14 Unsigned integer least significant byte 1st 15 Signed integer most significant byte 1st 16 Signed integer least significant byte 1st 17 4 byt...

Page 27: ...are written in the following order transmit receive overrun and watchdog counts Each is a count from 0 to 255 The transmit receive and overrun counters are measures of the errors on the CAN Bus netwo...

Page 28: ...is not involved in bus activities One of the error counters is equal to or greater than 96 See data type 28 above for details of the error counters and how to reset them Read the signature and version...

Page 29: ...received correctly from an external node are acknowledged 2 Self reception A frame transmitted from the SDM CAN that was acknowledged by an external node will also be received by the SDM CAN but no re...

Page 30: ...nd so the SDM CAN supports both methods of referencing the start point By default the SDM CAN follows the ISO standard and the LSB is referenced to the right most bit of the frame The bit number can r...

Page 31: ...ckets as possible In this case the interrupt facility can be used to give capture of the CAN data as a higher priority over the normal scheduled measurement tasks allowing the data to be captured at t...

Page 32: ...liseconds If the I O terminal is held at 5V by another peripheral it will wait until the I O terminal goes low and has been low for 50 milliseconds before trying to drive it high to 5V again The I O l...

Page 33: ...g and triggering Operating systems V3 include the ability for the user data logger program to attach a buffer of 256 frames to any receiving CAN ID up to a limit of 25 different ID s If the user progr...

Page 34: ...sed to create the buffer and attach it to a particular ID Reading Polling Buffer To implement this buffer function the read switch Data type 33 is used as follows a If start bit number parameter 9 is...

Page 35: ...etrieve Data from CAN network 1 SDM CAN P118 1 0 SDM Address 2 4 Time Quanta 3 5 Tseg1 4 2 Tseg2 5 1024 ID Bits 0 10 for 11 bit CAN ID 6 7680 ID Bits 11 23 7 12 ID Bits 24 28 8 2 Rx unsigned int LSB 1...

Page 36: ...ponent of 10 3 3 Z Loc Switches Send switch settings to SDM CAN 7 SDM CAN P118 1 0 SDM Address 2 2 Time Quanta 3 5 Tseg1 4 2 Tseg2 5 1 ID Bits 0 10 6 0 ID Bits 11 23 7 0 ID Bits 24 28 8 32 Set switche...

Page 37: ...check the jumper settings inside the SDM CAN if enabling transmission as the default setting is for transmission to be disabled in hardware NOTE 3 5 3 Building and Sending Data Frames The following t...

Page 38: ...CAN internal software switches 1 If Flag Port P91 1 11 Do if Flag 1 is High 2 30 Then Do Load input location with value for switches 2 Z F P30 1 10 F 2 0 Exponent of 10 3 3 Z Loc Switches Send switch...

Page 39: ...ng the Group Trigger The SDM Group Trigger controls SDM devices that support the Group Trigger protocol including the SDM CAN All Group Trigger devices are triggered to make simultaneous measurements...

Page 40: ...7 12 ID Bits 24 28 8 2 Rx unsigned int LSB 1st 9 33 Start Bit No 10 16 No of Bits 11 1 No of Values 12 2 Loc Eng_1 13 0 125 Mult 14 0 0 Offset Retrieve Data from CAN network B 8 SDM CAN P118 1 01 SDM...

Page 41: ...CR9000 and CR5000 to allow users to run a program at more than 200Hz with the SDM CAN It gives a 5 fold improvement in performance over normal mode Block mode operation is activated by using data typ...

Page 42: ...SEG2 ID DATATYPE STARTBIT NUMBITS NUMVALS MULT OFFSET where CANDATA is a variable or array which either holds data to be transmitted or will hold data that is to be read from the CAN Bus ADDRESS is th...

Page 43: ...CANREP1 1 Repetitions Const ADDR1 0 SDM address of SDM CAN Module Const DTYPE1 2 Collect and retrieve data values Const STBIT1 33 Start position in data frame Const NBITS1 16 Number of bits value Con...

Page 44: ...twork Parameters Const TQUANT 4 Set SDM CAN to 250K Const TSEG1 5 Network speed Const TSEG2 2 Data Frame Parameters ___________________________CANbus Block1_________________________ Send switch value...

Page 45: ...nsmit Data on to CAN network CanBus TBlk1 ADDR2 TQUANT TSEG1 TSEG2 1 DTYPE2 STBIT2 NBITS2 NVALS2 CMULT2 COSET2 Next Scan Loop up for the next scan EndProg Program ends here The default setting for the...

Page 46: ...ry 1 Secs non burst __________________________ CAN Blocks __________________________ Read status of digital I O port return value to NewData variable ReadIO NewData 7 B1 When digital I O port is high...

Page 47: ...t three Carriage Returns so the SDM CAN can recognise the baud rate at which you are communicating As soon as your baud rate has been detected the SDM CAN will return the prompt CAN to your terminal w...

Page 48: ...hen be set to and stay at this baud rate until the changed by the datalogger following a re compilation of the program by the user or by a datalogger SDM communications error which will force the SDM...

Page 49: ...and the 3rd n is number of frame buffers Bus mode indicates the following states 0 Bus On the SDM CAN is involved in bus activities Error counters are less than 96 1 Bus On the SDM CAN is involved in...

Page 50: ...nnected to a datalogger To load the new operating system take the following steps Run the CSOS software and set up the communications parameters to specify the COM port to which the SDM CAN is connect...

Page 51: ...as which data type to use which Buffer Set it should get the data from and where its New data flag is located plus a large amount of other information The New data flags are set when new data arrives...

Page 52: ...is ready for transmission The SDM CAN will scan the buffers checking this flag in each buffer that is set for transmission When it finds a flag that is set it will first check if the transmitter is b...

Page 53: ...ta frame unsigned integer MSB first OR ed 14 Build data frame unsigned integer LSB first OR ed 15 Build data frame signed integer MSB first OR ed 16 Build data frame signed integer LSB first OR ed 17...

Page 54: ...equest 32 Set SDM CAN s internal switches Switch Code Description A 0 Not used B 0 returns the last value captured default 1 returns 99999 if value already read by datalogger C 0 Disable interrupts de...

Page 55: ...ield 1 bit DP Data Page Field 1 bit PF PDU Format Field 8 bits PS PDU Specific Field 8 bits SA Source Address Field 8 bits Table C 1 Mapping of the J1939 Fields into a 29 Bit Identifier Bit 28 27 26 2...

Page 56: ...1 87654321 Details of specific data frame values can be found in the SAE J1939 standard NOTE C 4 Retrieving J1939 Accelerator Pedal Position Data using a CR9000 CR5000 Bus Speed 250k Baud C 4 1 Encodi...

Page 57: ...4321 87654321 87654321 87654321 87654321 87654321 87654321 The start bit for this value is 49 as it is the least significant bit of the data value within the data frame that this parameter refers to A...

Page 58: ...urrent system constraints the ID parameter must be entered directly into the CanBus instruction NOTE C 5 Retrieving J1939 Accelerator Pedal Position Data using a CR23X CR10X Bus Speed 250k Baud C 5 1...

Page 59: ...nverted to 768010 and used as the second ID parameter The third value is made up of bits 24 28 which is 011002 this is converted to 1210 and used as the third ID parameter C 5 2 Finding the Start Bit...

Page 60: ...SDM CAN CAN Bus Interface User Guide 13 0 125 Mult 14 0 0 Offset Table 2 Program 02 0 0000 Execution Interval seconds Table 3 Subroutines End Program C 6...

Page 61: ...4 For the Left Hand Reference some manufacturers may number the bits in the following order Left Hand Ref 8 1 16 9 24 17 32 25 40 33 48 41 56 49 64 57 An additional variation is that sometimes the bit...

Page 62: ...ss 2 1 Time quanta 3 5 Tseg1 4 4 Tseg2 5 1001 ID Bits 0 10 6 0000 ID Bits 11 23 7 00 ID Bits 24 28 8 2 Rx unsigned int LSB 1st 9 8 Start Bit No 10 16 No of Bits 11 1 No of Values 12 1 Loc value_A 13 1...

Page 63: ...SDM Address 2 1 Time quanta 3 5 Tseg1 4 4 Tseg2 5 1001 ID Bits 0 10 6 0000 ID Bits 11 23 7 00 ID Bits 24 28 8 2 Rx unsigned int LSB 1st 9 24 Start Bit No 10 16 No of Bits 11 2 No of Values 12 1 Loc va...

Page 64: ...0 SDM Address 2 1 Time quanta 3 5 Tseg1 4 4 Tseg2 5 1001 ID Bits 0 10 6 0000 ID Bits 11 23 7 00 ID Bits 24 28 8 2 Rx unsigned int LSB 1st 9 12 Start Bit No 10 12 No of Bits 11 2 No of Values 12 1 Loc...

Page 65: ...Time quanta 3 5 Tseg1 4 4 Tseg2 5 1001 ID Bits 0 10 6 0000 ID Bits 11 23 7 00 ID Bits 24 28 8 4 Rx signed int LSB 1st 9 4 Start Bit No 10 12 No of Bits 11 1 No of Values 12 1 Loc value_A 13 1 0 Mult 1...

Page 66: ...d reference 2 SDM CAN P118 1 00 SDM Address 2 1 Time quanta 3 5 Tseg1 4 4 Tseg2 5 1001 ID Bits 0 10 6 0000 ID Bits 11 23 7 00 ID Bits 24 28 8 6 Rx real IEEE4 LSB 1st 9 16 Start Bit No 10 32 No of Bits...

Page 67: ...eg1 4 4 Tseg2 5 1001 ID Bits 0 10 6 0000 ID Bits 11 23 7 00 ID Bits 24 28 8 1 Rx unsigned int MSB 1st 9 16 Start Bit No 10 16 No of Bits 11 1 No of Values 12 1 Loc value_A 13 1 0 Mult 14 0 0 Offset 32...

Page 68: ...SDM Address 2 1 Time quanta 3 5 Tseg1 4 4 Tseg2 5 1001 ID Bits 0 10 6 0000 ID Bits 11 23 7 00 ID Bits 24 28 8 3 Rx signed int MSB 1st 9 32 Start Bit No 10 16 No of Bits 11 2 No of Values 12 1 Loc valu...

Page 69: ...ference 2 SDM CAN P118 1 00 SDM Address 2 1 Time quanta 3 5 Tseg1 4 4 Tseg2 5 1001 ID Bits 0 10 6 0000 ID Bits 11 23 7 00 ID Bits 24 28 8 1 Rx unsigned int MSB 1st 9 24 Start Bit No 10 12 No of Bits 1...

Page 70: ...quanta 3 5 Tseg1 4 4 Tseg2 5 1001 ID Bits 0 10 6 0000 ID Bits 11 23 7 00 ID Bits 24 28 8 1 Rx unsigned int MSB 1st 9 16 Start Bit No 10 12 No of Bits 11 1 No of Values 12 1 Loc value_A 13 1 0 Mult 14...

Page 71: ...Rx real IEEE4 MSB 1st 9 1 Start Bit No 10 32 No of Bits 11 1 No of Values 12 1 Loc value_A 13 1 0 Mult 14 0 0 Offset Start bit parameter 09 Left Hand reference 2 SDM CAN P118 1 00 SDM Address 2 1 Tim...

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