SDM-SIO4 4-Channel Serial I/O Interface User Guide Issued 17.3.97 Copyright 1997 Campbell Scientific Ltd.
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Contents Section 1. Introduction ..................................................... 1-1 1.1 What is the SDM-SIO4?.................................................................................1-1 1.2 Specifications .................................................................................................1-3 1.2.1 Serial Ports............................................................................................1-3 1.2.2 SDM Port...............................................................
5.2.6 Command 5: Status .............................................................................5-4 5.2.7 Command 6: Flush Transmit Buffer....................................................5-5 5.2.8 Command 7: Activate Command Line................................................5-5 5.2.9 Command 8: Poll Tx Buffers for Data ................................................5-5 5.2.10 Command 9: Flush Converted Data Buffer .......................................5-5 5.2.
Section 1. Introduction The SDM-SIO4 has four configurable serial RS232 ports which allow it to be connected to intelligent serial sensors, display boards, printers or satellite links. It can also be used in many other applications where the data is transferred in a serial fashion. This device is designed to send data to and receive data from the sensors, and process it in parallel with the datalogger’s own program sequence, thus making the complete datalogging system faster and more efficient.
SDM-SIO4 4-Channel Serial I/O Interface User Guide Command Line Switch Status LED PORT Handshake Line ½ ¾ Handshake Control ¾ ¿ Tx Tx Buffer Rx Rx Buffer À ¿ 0 ¿ 0 1 ½ CRC/SIG Driver ¿ À ¿ ¾ ¿ ¿ À Filter Driver Datalogger can Execute Command Line Commands À Format Driver & User Strings To Other Ports ½ Command Line Control CRC/SIG Driver À ¿ À 1 Switches Go to 1 if command line active Converted Data Buffer K K K To Other Ports ¾ ¿ À Datalogger Command Control ½ Cont
Section 1 . Introduction 1.2 Specifications 1.2.1 Serial Ports The SDM-SIO4 has four serial ports which can be configured independently to use different serial data formats and baud rates (from 25 to 115,200 baud). These ports are 0-5V logic or ±5V for RS232 and are configured similar to a PC ‘AT’ style DTE serial port. Handshaking, to control the flow of data to and from a sensor, can be done by the datalogger or SDM-SIO4 if needed, and can be in the form of hardware or software protocols.
SDM-SIO4 4-Channel Serial I/O Interface User Guide 1.2.2 SDM Port This serial port is to connect to the SDM port of the datalogger, e.g. via C1, C2 and C3 on a CR10X. The port is a set of screw terminals marked C1, C2, C3, I/O, +12 and G. C3 is the Synchronous Device Enable line, C1 is the Data line, C2 is the Clock line and I/O is a special-purpose Interrupt line. The Interrupt line can be used with some dataloggers to tell the datalogger to collect data from the sensor.
Section 1 . Introduction 1.2.6 Other Key Features • An internal lithium battery which retains configuration information (estimated life 10 years) • A built-in system watchdog which will reset the processor in the event of a crash caused by transients, etc. • A multi-tasking operating system allowing concurrent transmission and receipt of data on all ports. This allows the receipt and processing of data from all four serial ports concurrently at 9600 baud.
Section 2. Installation and Hardware Set-Up The SDM-SIO4 is designed to be mounted on an enclosure chassis plate using the two mounting holes in the tabs on the side of the case. Before installation, it is necessary to set up the address of the SDM-SIO4 and also the mode of operation of each serial port. These settings are determined by jumpers inside the case. To access these, remove the four M3 screws and lift the lid off.
SDM-SIO4 User Guide 2.2 Selecting RS232 or 5V Logic for Each Port The output voltage levels of each serial port can be set to either: • Logic level output: +5V (high) / 0V (low) or • RS232 output: +5V (high) / -5V (low) (compatible with RS232 driver requirements). The logic level output is used when driving a logic level compatible device, e.g. an SC32A, or where quiescent current is a concern.
Section 2. Installation and Hardware Set-Up • Electrical noise causing possible loss or corruption of serial data. • Electrical noise being transferred back to the datalogger causing errors on analogue measurements. • Long term damage in the form of corrosion caused by current flowing along electro-chemical gradients.
Section 3. Understanding How the SDM-SIO4 Handles Data For simple applications the SDM-SIO4 can be configured and controlled from the datalogger alone, using the datalogger program instruction P113 (CR10X and CR7 dataloggers only). Future developments will include support for other dataloggers. More complicated applications require configuration of the SDM-SIO4 using the ‘command line’ function on a PC running a terminal emulator.
SDM-SIO4 User Guide NOTE The hex. number must always be two ASCII characters. Control characters can be entered for all commands in a similar way: • ^M is carriage return, ^J line feed etc. • ^^ means ^ • "" means " • ]] means ] • && means & • &0d means line feed • &hex,hex used to enter 2-character hex. codes (0-9, A-F) 3.2 Input Filters Input filters are used to convert received data into a form that is easy for the datalogger to process.
Section 3. Understanding How the SDM-SIO4 Handles Data See Section 5 – ‘Programming the Datalogger’. Filter Strings These are used to define how to filter incoming data from a port into a format the datalogger can use. This is done by having a user-defined filter string pre-stored in the battery-backed memory of the SDM-SIO4. These strings have to be created via the command line (see Section 4), in a similar fashion to the format strings. The filter commands are as follows: • An Define a filter time-out.
SDM-SIO4 User Guide • i[ ] Scan until any ASCII characters entered between the brackets are encountered. The maximum number of characters between the brackets is 255. Note that this filter does not remove the matched character from the buffer. • nn Discard ‘n’ bytes. ‘n’ can be in the range of 0-255. • Nn Read ‘n’ bytes. ‘n’ can be in the range of 0-255 (not converted to Campbell Scientific floating point).
Section 3. Understanding How the SDM-SIO4 Handles Data 2. n8 discards everything up to 12.65V. 3. F converts the number to Campbell Scientific floating point. If a valid number is not found -99999 is sent to the datalogger. 4. i[c] waits for the trigger character ‘c’ of ‘current’. 5. n8 discards everything up to 12mA. 6. F converts the number to Campbell Scientific floating point. If a number is not found -99999 is sent to the datalogger. This filter will repeat the above operations on all incoming values.
SDM-SIO4 User Guide • Convert a location sent into a 16-bit binary word. If this option is selected an extra ASCII character/delimiter can be added to the end of the 16-bit word sent. See Section 5 – ‘Programming the Datalogger’. 3.3.2 Output Format Strings These allow either just long strings to be sent from the SDM-SIO4 or a combination of string data plus data from a datalogger input location. This type of format is normally set up from the ‘command line’.
Section 3. Understanding How the SDM-SIO4 Handles Data Table 4 Fixed Strings Currently Allocated String number String (enclosed in quotes) 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 ‘+0000000000123.45670000000000CrLf’ ‘Voltage’ ‘Amps’ ‘Watts’ ‘Joules’ ‘Temperature’ ‘Pressure’ ‘Speed’ ‘Power’ ‘Depth’ ‘Length’ ‘Height’ ‘Enter’ ‘Password’ ‘Correct’ ‘Incorrect’ ‘Overrange’ The ASCII characters: carriage return, linefeed.
SDM-SIO4 User Guide z273 – This outputs the fixed string ‘CrLf (carriage return line feed)’. *Table 1 Program 01: 2 Execution Interval (seconds) ;get battery voltage. 1: Batt Voltage (P10) 1: 2 Loc [ Batt_v ] ;get panel temperature. 2: Internal Temperature (P17) 1: 1 Loc [ Temp_C ] ;send battery voltage and temperature to port 2 on the SDM-SIO4. 3: 1: 2: 3: 4: 5: 6: 7: 8: 9: 10: SDM-SIO4 1 0 2 2304 9123 0 2 1 1.0 0.
Section 4. Programming the SDM-SIO4 This section gives both the basic commands and advanced command line options which allow testing and advanced configuration of the SDM-SIO4. 4.1 Command Line Operation and Structure To use the command line mode, connect a computer to port 1 of the SDM-SIO4. The computer should run a terminal emulation program (e.g. GraphTerm) which is set to 9600 baud, 8 data bits and 1 stop bit. If connecting to a PC you will need a null modem cable.
SDM-SIO4 User Guide Control characters can be entered for all commands in a similar way: • ^M is carriage return, ^J line feed etc. • ^^ means ^ • "" means " • ]] means ] • && means & • &0d means line feed • &hex,hex used to enter 2-character hex. codes (0-9, A-F) 4.3 Basic Commands fltst [string number] ["filter definition"] This command stores a filter definition to a string number 0..255. Example: fltst 22 "ccci[x]Fs" The above example stores the filter definition in filter string 22.
Section 4. Programming the SDM-SIO4 because they are compiled. exit This command exits the command line and returns port 1 of the SDM-SIO4 to normal operation. 4.4 Advanced Commands version This returns the internal EPROM part number, signature and the string signature if good or 0 if bad. This will give the same signature as Campbell Scientific’s SIG.COM PC program. portset [port#] [baud#] [data length] [stop bits] [parity] [handshake mode] [delay] This sets up the port 1..
SDM-SIO4 User Guide WD n WDERR n WDADDR n WD n is a count of the number of watchdog resets, WDERR is the number of the last task that crashed and WDADDR is the address at which the crash was found. NC 0-9 This is the number of SDM commands the datalogger sent to the SDM-SIO4 that the SDM-SIO4 did not recognise. This counter may be incremented when the program is first compiled in the datalogger due to the auto speed detection of the datalogger.
Section 4. Programming the SDM-SIO4 testio [test#] This is used by Campbell Scientific for test purposes. Each test command is carried out for 2 seconds. Test# can be in the range 0-255; only five test numbers are currently valid, as shown below.
Section 5. Programming the Datalogger The datalogger instruction specific to the SDM-SIO4 is P113 (CR7 and CR10/10X only). (Please check with Campbell Scientific to see if your version of the operating system supports this.) The instruction has the following format: Parameter No. Description 01 02 03 04 05 06 07 08 09 10 Reps (number of adjacent addressed SDM-SIO4s) Address of SDM-SIO4 (0..15) Mode (0..5) Command (0..9999). First command option (0..9999) Second command option (0..
SDM-SIO4 User Guide 5.1.5 Parameter 7 — Values per Rep This determines how many values to send or receive, starting from the specified input location (parameter 8). Data can be either 4-byte floating point values or single bytes, determined by the SDM-SIO4 command number. Some commands require no input or output of values; for these commands this parameter would be set to zero. 5.1.
Section 5. Programming the Datalogger 5.2.1 Understanding Parameter Options and Returned Values NOTE In the following examples, ‘x’ indicates a single digit from 0 to 9. When the command requires or returns values, each digit, or combination of digits, can signify either a value, flag or setting.
SDM-SIO4 User Guide 5.2.3 Command 2: Signatures This command gets the SDM-SIO4 EPROM signature and the string memory area signature; the two values are written into consecutive input locations. If the signatures are zero then there could be corrupt data. Values per repetition = 2 5.2.4 Command 3: Flush all Receive Buffers Stored data in the SDM-SIO4 relevant to the port is also erased with this command. Values per repetition = 0 5.2.
Section 5. Programming the Datalogger If any of these four digits is greater than zero then data is available. Values per repetition = 2 5.2.7 Command 6: Flush Transmit Buffer This command flushes the SDM-SIO4 transmit buffer of data it is waiting to send. Values per repetition = 0 5.2.8 Command 7: Activate Command Line This command simulates pressing the push button on the SDM-SIO4 which activates the command line mode on the port determined by the mode.
SDM-SIO4 User Guide 5.2.12 Command 67: Get Return Code This command gets the return error code and places it into a specified location. Command 67 is used in conjunction with command 321 and provides a single return code value which indicates if the command was successful or not. See Section 5.6 for the return codes. Values per repetition = 1 5.2.13 Command 320: Send Byte Data to SDM-SIO4 This command transmits bytes of data (one per input location) to the SDM-SIO4 for retransmission.
Section 5. Programming the Datalogger P65 Bulk load 1:102 f 2:108 l 3:116 t 4:115 s 5:116 t 6:32 ascii space 7:50 2 8:53 5 9:1 First location to store the first lot of 8 characters. P65 Bulk load 1:32 ascii space 2:34 “ 3:102 f 4:102 f 5:67 C 6:99 c 7:34 “ 8:0 9:9 First location to store second lot of characters. ;execute the command line string. P113 1:1 2:0 3:1 4:321 Command to execute command line command. 5:0 6:0 7:15 Length of command line string. ;no.
SDM-SIO4 User Guide ;set flag one so that set-up will only be done once. P86 11 ;end of set-up. P95 NOTE If you use the RAMTEST command you will have to wait a minimum of 6 seconds for it to complete before you try to execute another P113. Some Dataloggers do not support P65 Bulk Load. In that case you would have to use a P30 Instruction for each ASCII character. 5.2.
Section 5. Programming the Datalogger Second Value Returned CTS status (0=CTS low, 1=CTS high) | DSR status (0=DSR low, 1=DSR high) | | RI status (see below) | | | DCD status (0=DCD low, 1=DCD high) | | | | x x x x For the RI (Ring Indicator): 0 = no trailing edge seen since last read 1 = trailing edge seen since last read Third Value Returned Framing errors | | Overrun errors | | | | x x x x Framing errors is a count from 0-99.
SDM-SIO4 User Guide Break reset: 0 Do nothing 1 Reset line break count to zero Framing reset: 0 Do nothing 1 Reset framing error count to zero Overrun reset: 0 Do nothing 1 Reset overrun error count to zero Parity reset: 0 Do nothing 1 Reset parity error count to zero 5.2.18 Command 1027: ‘Manual’ Handshake Mode In this mode, the datalogger can set DTR, RTS and XON/XOFF as required. Not used - set to zero.
Section 5.
SDM-SIO4 User Guide 5.2.20 Command 2054: Set Up Receive Filter This command clears all buffers relevant to the mode number and restarts the filter. Values per repetition = 0 NOTE With the string filter type the SDM-SIO4 buffers are not cleared.
Section 5. Programming the Datalogger Output Mode: 0 No output format string 1 Convert location to ASCII floating point. Add character/delimiter between values if enabled. The last value will not have a delimiter after it. 2 Convert location to ASCII hex pair. Add character/delimiter between values if enabled. The last value will not have a delimiter after it. 3 Convert location to 8-bit binary. Add character/delimiter between values if enabled. The last value will not have a delimiter after it.
SDM-SIO4 User Guide 5.2.22 Command 2305: Transmit Byte(s) By using P113 command 2305 it is possible to transmit either one or two bytes from the command options. If any command option is set to 999 then the byte will not be sent. The number range for each command option is 0-255 and 999. An example of its use is below: 1:SDM-SIO4 (P113) 1:1 Reps. 2:0 SDM address. 3:1 Mode, send bytes to port 1. 4:2305 Command. 5:13 Decimal number that represents Carriage Ret.
Section 5. Programming the Datalogger ;set serial mode to DTR, RTS always set, ignore CTS, 1 stop bit no parity, ;8 bit data length, 9600 baud and no handshake delay. 2: 1: 2: 3: 4: 5: 6: 7: 8: 9: 10: SDM-SIO4 1 0 1 2049 3146 0 0 0000 1.0 0.0 (P113) Reps Address Send/Receive Port 1 Command 1st Parameters 2nd Parameters Values per Rep Loc [ _________ ] Mult Offset ;set up a simple filter 1999 search for floating point number. 3: 1: 2: 3: 4: 5: 6: 7: 8: 9: 10: SDM-SIO4 1 0 1 2054 1999 0 0 0000 1.0 0.
SDM-SIO4 User Guide *Table 2 Program 02: 0.0000 Execution Interval (seconds) *Table 3 Subroutines End Program The normal configuration would include setting the speed and serial data format by calling the datalogger instruction with command 2049 and the relevant parameters. For the majority of sensor applications where data is returned in only one type of format to the SDM-SIO4, the receive data format filters can also be defined once only by using command 2054.
Section 5. Programming the Datalogger ^J^M – this is a way of entering control characters for carriage return/linefeed into a string The following program example works as follows: 1. The first P113 sets up a simple filter to search for floating point numbers. 2. The first parameter of this command is used to transmit a string which will prompt the sensor into taking measurements and then transmitting the numbers to the SDM-SIO4. 3.
SDM-SIO4 User Guide ;get data from SDM-SIO4 and put into locations 1 and 2. 3: 1: 2: 3: 4: 5: 6: 7: 8: 9: 10: SDM-SIO4 1 0 1 4 0 0 2 1 1.0 0.0 (P113) Reps Address Send/Receive Port 1 Command 1st Parameters 2nd Parameters Values per Rep Loc [ number ] Mult Offset ;At zero minutes into a 10 minute interval set the output ;so that the data from the sensor will be stored into ;final storage.
Section 5. Programming the Datalogger Example CR10X Program without Polling or Interrupts This simple program is an example for sensors that send data at random intervals. If no data was available when the datalogger asked for it then -99999 will be put into locations 1 and 2. An IF THEN structure could be used in the datalogger program to store only values that are not -99999.
SDM-SIO4 User Guide ;end of set up. 5: End (P95) ;get the two floating point values from the SDM-SIO4. 6: 1: 2: 3: 4: 5: 6: 7: 8: 9: 10: SDM-SIO4 1 0 1 4 0 0 2 1 1.0 0.0 (P113) Reps Address Send/Receive Port 1 Command 1st Parameters 2nd Parameters Values per Rep Loc [ Voltage ] Mult Offset ;Only set the output flag when the voltage is ;greater than or equal to -99998. 7: 1: 2: 3: 4: IF (X<=>F) (P89) 1 X Loc [ Voltage ] 3 >= -99998 F 10 Set Output Flag High (Flag 0) ;Time stamp.
Section 5. Programming the Datalogger x – this filter marks the start of the data set. In this case the data set is two floating point numbers. f – this filter searches for the first ASCII floating point number to convert. f – this filter searches for the second ASCII floating point number to convert. *Table 1 Program 01: 2 Execution Interval (seconds) ;do filter set-up only if flag one is clear. 1: If Flag/Port (P91) 1: 21 Do if Flag 1 is Low 2: 30 Then Do ;set up string filter.
SDM-SIO4 User Guide ;if value returned from poll is >=1 then data must be available. 7: 1: 2: 3: 4: IF (X<=>F) (P89) 2 X Loc [ poll 3 >= 1 F 30 Then Do ] ;get voltages into locations 3 and 4 if poll was true. 8: 1: 2: 3: 4: 5: 6: 7: 8: 9: 10: SDM-SIO4 1 0 1 4 0 0 2 3 1.0 0.0 (P113) Reps Address Send/Receive Port 1 Command 1st Parameters 2nd Parameters Values per Rep Loc [ voltage1 ] Mult Offset ;set the output flag so the data can be store to final storage.
Section 5. Programming the Datalogger – see ‘SDM Port’ in Section 1 for details. This should be connected to control port 8 for this example. A typical filter that could be used is as follows: fltst 200 "t[data]A5xff" This filter works as follows: t[data] – this filter waits for an exact string match before it starts the next filter. In this case it is waiting for the sensor to send the string ‘data’. A5 – this filter sets up a 250ms filter time out.
SDM-SIO4 User Guide ;end of IF 6: End (P95) *Table 2 Program 02: 0.0000 Execution Interval (seconds) *Table 3 Subroutines ;interrupt routine for control port 8 1: Beginning of Subroutine (P85) 1: 98 Subroutine 98 ;get voltages into locations 3 and 4 2: 1: 2: 3: 4: 5: 6: 7: 8: 9: 10: SDM-SIO4 1 0 1 4 0 0 2 3 1.0 0.
Section 5. Programming the Datalogger 5.4 Outputting Datalogger Data The SDM-SIO4 can be used to drive displays, printout devices and other outputonly systems. In this case after the initial configuration (as above) either simple data can be sent using commands 0320, 1025 or just data strings using 1024 or strings plus formatted data sent using command 2304. This program example will output the battery voltage and panel temperature from the datalogger locations using the SDM-SIO4 Output Formatter.
SDM-SIO4 User Guide *Table 2 Program 02: 0.0000 Execution Interval (seconds) *Table 3 Subroutines End Program 5.5 Flushing the Input and Output Buffers One important aspect of the SDM-SIO4 is that it will continue to collect data and store it in its buffers even if the datalogger program stops running. Care must be taken to ensure that data does not build up in the buffers and as a result either a buffer overflows, or data is collected which relates to a different time than anticipated.
Section 6. Data Error Detection Error detection by checksum, CRC or signatures is a way of detecting errors in data, either transmitted or received. This section gives details on how to use filter strings together with datalogger program examples to implement error detection methods. 6.1 Error Detection with the SDM-SIO4 Error detection is carried out to provide confidence that critical data is received/transmitted correctly.
SDM-SIO4 User Guide 3 CRC16-CCITT-IBM (Tag Receiver). 4 CRC32 standard. Polynomial x32+x26+x23+x22+x16+x12+x11+x10+x8+x7+x5+x4+x2+x+1. 5 CSI Signature (see Appendix C of the CR10X Manual). 6 Checksum using modulo 256. 7 Checksum using modulo 8192 (See Section 5 of the CR10X Manual). 8-255 For future use. Gn This filter type can be added to the filter string to mark the end of the string and the point where the sensor signature should be. It also sets the data type to use.
Section 6. Data Error Detection 6.2.1 Example of Using Received Data Filters If a sensor transmitted the following string: Frequency=12.34567HzBB3DCrLf then a user defined filter string would have to be used. The BB3D part of the string is the CRC sent in hex. from the sensor. To produce a filter string to deal with the sensor output you could type in the following command: FLTST 100 “T[Frequency=]xg2n10fCCG8” FLTST is the command to store a user defined filter from the command line.
SDM-SIO4 User Guide *Table 1 Program 01: 1.
Section 6. Data Error Detection ;if the value in location 1 is greater than zero then there must be data ;this assumes only one sensor is connected to the SDM-SIO4 7: 1: 2: 3: 4: IF (X<=>F) (P89) 1 X Loc [ _________ ] 3 >= 1 F 30 Then Do ;if data is available then get the value and put into location 2 8: 1: 2: 3: 4: 5: 6: 7: 8: 9: 10: SDM-SIO4 1 0 1 4 0 0 1 2 1 0 (P113) Reps Address Send/Receive Port 1 Command 1st Parameters 2nd Parameters Values per Rep Loc [ _________ ] Mult Offset ;end of get data.
SDM-SIO4 User Guide 1,2 3 4 5 6 7 CRC16 and CRC16-CCITT CRC16-CCITT-IBM CRC32 CSI Signature Checksum using modulo 256 Checksum using modulo 8192 0.159ms/char. 0.159ms/char. 0.369ms/char. 0.077ms/char. 0.066ms/char. 0.071ms/char. c The time for the different data types is shown below. Note that this is the time needed to convert the received signature into a known format and is done at the end of the signature calculation before the compare.
Section 6. Data Error Detection 5 CSI Signature (CR10X user manual section C-4). 6 Check sum using modulo 256. 7 Check sum using modulo 8192 (CR10X user manual section 5-2). 8-255 reserved for future use. Gn This formatter type can be put into the formatter string to mark the end of the string and the point at which the signature should be transmitted. It also sets the data type to use. ‘n’ can be in the range of 0-255 which indicates the data type to use.
SDM-SIO4 User Guide 6.3.2 CR10X Program Example A typical CR10X datalogger program to work with the above formatter is shown below. The program assumes that the SDM-SIO4 is set to address 0, the sensor is connected to port 1 of the SDM-SIO4 and the port settings, baud rate etc have been set. The output from the SDM-SIO4 is every second: *Table 1 Program 01: 1.
Section 6. Data Error Detection *Table 1 Program 01: 1.0 Execution Interval (seconds) ;use formatter string 100 to set up the CRC16 on port 1 1: 1: 2: 3: 4: 5: 6: 7: 8: 9: 10: SDM-SIO4 1 0 1 2304 9100 0 0 0000 1 0 (P113) Reps Address Send/Receive Port 1 Command 1st Parameters 2nd Parameters Values per Rep Loc [ _________ ] Mult Offset ;A minimum delay of 1ms is required after this command 2: 1: 2: 3: 4: Excitation with Delay (P22) 1 Ex Channel 0 Delay W/Ex (units = 0.
SDM-SIO4 User Guide ;use formatter string 102 and output datalogger location 1 as ASCII floating point ;to port 1 and then output the calculated ASCII hex CRC16 6: 1: 2: 3: 4: 5: 6: 7: 8: 9: 10: SDM-SIO4 1 0 1 2304 9102 0 1 0000 1 0 (P113) Reps Address Send/Receive Port 1 Command 1st Parameters 2nd Parameters Values per Rep Loc [ _________ ] Mult Offset *Table 2 Program 02: 0.0 Execution Interval (seconds) *Table 3 Subroutines End Program The string transmitted from port one might be ‘some dataYZ+234.
Section 6. Data Error Detection 1 2,3 4,5 6 7 8 9 8 bit binary 16 bit binary 32 bit binary ASCII decimal 8 bit ASCII hex 16 bit ASCII hex 32 bit ASCII hex 0.155ms 0.216ms 0.334ms 1.125ms 0.226ms 0.355ms 0.613ms The above timings are preliminary. d With the CRC32 and CRC16-CCITT there is a extra 0.19ms for an additional calculation. This is required as part of the CRC algorithm.
Appendix A. ASCII Table American Standard Code for Information Interchange Decimal Values and Characters (X3.4-1968) Dec. Char.
Appendix B. Serial Port Data Transfer Modes This appendix describes the serial port set-up in some detail. Please note that the numerical option codes vary between the command line set-up and the datalogger command set-up. The ones listed below are those for the command line mode. B.1 Baud rates The SDM-SIO4 ports can support 16 baud rates if set up from the command line but only 9 are available from datalogger set-up using SDM commands. An asterisk indicates not available in SDM command mode:0.
SDM-SIO4 4-Channel Serial I/O Interface B.4 Parity Bits Parity can be enabled and set to either odd or even. 0. No parity set 1. Odd parity set 2. Even parity set B.5 Serial Handshake Modes You can select different kinds of handshaking from none at all, hardware (DTR, CTS etc.) and XON/XOFF. On modes 0 and 1 there is a user-set delay (0..254 x 50ms) between CTS being set and data being sent; this allows time for sensors to power up. 0. Leave as previously set. 1.
