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NI-DNET User Manual - National Instruments

1. Slave Slave Slave Slave MAC ID 9 MAC ID 11 MAC ID 12 MAC ID 13 Figure 5 COS Cyclic 1 0 Example National Instruments A 11 NI DNET User Manual Appendix DeviceNet Overview Assembly Objects One of the more important objects in the DeviceNet Specification is the Assembly Object There are two types of Assembly Object input assemblies and output assemblies Assembly objects act like a switchboard routing incoming and outgoing data to its proper location within the device Output assemblies receive an output message from an I O connection and distribute its contents to multiple attributes within the slave Input assemblies gather multiple attributes within the slave for transmission on an I O connection Figure A 6 shows the operation of input and output assemblies Instance Attributes Instance Instance Attributes Attributes Output Assembly Associated Input Assembly Associated with an Output Message with an Input Message Such as a Poll Command Such as a Poll Response NI DNET User Manual Figure A 6 Input and Output Assemblies As a more specific example consider a DeviceNet photoelectric sensor photoeye or a limit switch These devices contain a single instance of a class called the Presence Sensi
2. NI DNET User Manual Each C language NI DNET function returns a value that indicates the status of the function call This status value is zero for success greater than zero for a warning and less than zero for an error After every call to an NI DNET function your program should check to see if the return status is nonzero If so call the ncStatusToString function to obtain an ASCII string which describes the error warning You can then use standard C function such as printf to display this ASCII string Your application code should check the status returned from every NI DNET function If an error is detected you should close all NI DNET handles then exit the application If a warning is detected you can display a message for debugging purposes or simply ignore the warning For more information on status checking refer to the ncStatusToString function in the NI DNET Programmer Reference Manual 3 12 ni com NI DNET Programming Technigues This chapter describes various technigues to help you program your NI DNET application The technigues include configuration of I O connection timing using I O data assemblies using explicit messaging and handling multiple devices Configuring 1 0 Connections This section provides information on how I O connections relate to one another and how your configuration of I O connection timing can affect the overall performance of your DeviceNet system The various types of
3. a a T T T 0 ms 5ms 10 ms 15 ms 20 ms Figure 4 1 Strobed 1 0 Timing Example NI DNET User Manual 4 2 ni com O National Instruments Chapter 4 NI DNET Programming Technigues Polled 1 0 Polled I O connections use a separate poll command and response message for each device The overall scheme that NI DNET uses to time polled I O connections is determined by the Po11Mode parameter of ncopenDnetIntf This PollMode parameter applies to all polled I O connections all calls to ncOpenDnetIO with ConnectionType of Poll The following sections describe different schemes you can use for polled I O Scanned Polling Youcanset the ExpPacketRate of each polled I O connection to the same value used for all strobed I O Using a common ExpPacketRate for all strobed and polled I O is referred to as scanned I O Scanned I O is also referred to as scanned polling with respect to polled I O connections When you use scanned I O NI DNET transmits all strobe and poll command messages onto the network in quick succession Scanned I O is a simple efficient way to handle I O connections that require similar response rates With scanned I O the master knows that all strobe and poll commands go out at the same time Therefore the master does not need to manage individual timers thus optimizing processing overhead Scanned I O also provides overall consistency If a given DeviceNet system uses only scanned I O you know that all h
4. 1 6 ni com Chapter 1 NI DNET Software Overview Use the I O Object to do the following Read data from the most recent message received on the T O connection ncReadDnet10 Write data for the next message produced on the I O connection ncWriteDnetIO Figure 1 2 shows an example of how NI DNET objects can be used to communicate on a DeviceNet network This example shows three DeviceNet devices The first device at MAC ID 1 is the National Instruments DeviceNet interface The second device at MAC ID 5 uses NI DNET to access a polled and a COS I O connection simultaneously The third device at MAC ID 8 uses NI DNET to access an explicit messaging connection and a strobed I O connection Access to device at MAC ID 5 Access to device at MAC ID 8 Device MAC ID 5 Object Connection Type COS Device MAC ID 5 Connection Type Poll Object Device MAC ID 8 I O Object Device MAC ID 8 Connection Type Strobe Explicit Messaging I O Object Your National Instruments DeviceNet Interface Interface MAC ID 1 Baud Rate 500K Interface Object Using NI CAN Figure 1 2 NI DNET Objects for a Network of Three Devices with NI DNET O National Instruments Controller Area Network CAN is the low level protocol used for DeviceNet communications In addition to the NI DNET functions your National Instruments
5. device conforms to a standard device profile the I O assemblies are defined within the DeviceNet Specification 4 8 ni com Chapter 4 NI DNET Programming Technigues e Some device vendors provide comments about I O assemblies in an Electronic Data Sheet EDS The EDS file is a text file whose format is defined by the DeviceNet Specification e Ask the device s vendor if they have filled out a DeviceNet compliance statement This form is located at the front of the DeviceNet Specification and it provides information about the device including its I O assemblies After you open an NI DNET I O Object and start communication you use the ncWriteDnetIO function to write an output assembly for a device and the ncReadDnet IO function to read an input assembly received from a remote device Both of these functions access the entire assembly as an array of bytes In most cases the array of bytes for an input or output assembly contains more than one value In DeviceNet terminology an individual data value within an I O assembly is referred to as a member Documentation for the members of an input or output assembly includes the position of each member in the assembly often shown as a table with byte bit offsets and a listing of the attribute in the device that each member represents often shown as class instance and attribute identifiers For standard device profiles the I O assemblies are documented in the device profile s specifi
6. E 8 8 noooo m u FOOTER 1 Power Supply Jumper J6 3 Assembly Number 5 Serial Number 2 Power Supply Jumper J5 4 Product Name National Instruments Figure B 6 8461 Parts Locator Diagram Connecting pins 1 and 2 of a jumper configures the PXI 8461 physical layer to be powered externally from the bus cable power In this configuration the power must be supplied on the V and V pins on the port connector The jumper must be in this position for the DeviceNet interface to be compliant with the DeviceNet Specification Connecting pins 2 and 3 of a jumper configures the PXI 8461 physical layer to be powered internally from the board In this configuration the V signal serves as the reference ground for the isolated signals The PCMCIA CAN is shipped with the bus power version of the PCMCIA CAN cable An internally powered version of the PCMCIA CAN cable can be ordered from National Instruments B 5 NI DNET User Manual Appendix Cabling Requirements Cable Specifications Cables should meet the requirements of the DeviceNet cable specification DeviceNet cabling requirements can be found in the DeviceNet Specification Belden cable 3084A meets all of those requirements and should be suitable for most applications Cable Lengths The allowable cable length is affected by the characteristics of the cabling and the desired
7. Controller Area Network CAN for High Speed Communication e DeviceNet Specification Version 2 0 Open DeviceNet Vendor Association e CompactPCI Specification Revision 2 0 PCI Industrial Computers Manufacturers Group e PXI Hardware Specification Revision 2 1 National Instruments Corporation X ni com National Instruments About This Manual PXI Software Specification Revision 2 1 National Instruments Corporation LabVIEW online reference ODVA website www odva org Microsoft Win32 Software Development Kit SDK online help Xi NI DNET User Manual NI DNET Software Overview The DeviceNet software provided with National Instruments DeviceNet hardware is called NI DNET This section provides an overview of the NI DNET software Installation and Configuration Measurement 8 Automation Explorer MAX Measurement amp Automation Explorer MAX provides access to all of your National Instruments products Like other NI software products NI DNET uses MAX as the centralized location for all configuration and tools To launch MAX select the Measurement amp Automation shortcut on your desktop or within your Windows Programs menu under National Instruments Measurement amp Automation For information about the NI DNET software within MAX consult the MAX online help A reference is in the MAX Help menu under Help Topics NI DNET View help for items in the MAX Configuration tree by using the built
8. ERRORS ON THE PART OF THE USER OR APPLICATIONS DESIGNER ADVERSE FACTORS SUCH AS THESE ARE HEREAFTER COLLECTIVELY TERMED SYSTEM FAILURES ANY APPLICATION WHERE A SYSTEM FAILURE WOULD CREATE A RISK OF HARM TO PROPERTY OR PERSONS INCLUDING THE RISK OF BODILY INJURY AND DEATH SHOULD NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRONIC SYSTEM DUE TO THE RISK OF SYSTEM FAILURE TO AVOID DAMAGE INJURY OR DEATH THE USER OR APPLICATION DESIGNER MUST TAKE REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES INCLUDING BUT NOT LIMITED TO BACK UP OR SHUT DOWN MECHANISMS BECAUSE EACH END USER SYSTEM IS CUSTOMIZED AND DIFFERS FROM NATIONAL INSTRUMENTS TESTING PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER MAY USE NATIONAL INSTRUMENTS PRODUCTS IN COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT EVALUATED OR CONTEMPLATED BY NATIONAL INSTRUMENTS THE USER OR APPLICATION DESIGNER IS ULTIMATELY RESPONSIBLE FOR VERIFYING AND VALIDATING THE SUITABILITY OF NATIONAL INSTRUMENTS PRODUCTS WHENEVER NATIONAL INSTRUMENTS PRODUCTS ARE INCORPORATED IN A SYSTEM OR APPLICATION INCLUDING WITHOUT LIMITATION THE APPROPRIATE DESIGN PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION Contents About This Manual Howto Us the Manual Set 5 ttr ret e REINES Pa exero i ix CONVENTIONS ii ene OUI E CH VETERE uksed vara CRISE UAE van ka palad Related Documentation 25e tet tele e e PR a be PECORE ta X Chapter 1 NI DNET Software Over
9. I O connections provided by DeviceNet are described in Chapter 1 NI DNET Software Overview In a master slave DeviceNet I O system the master determines the timing of all O communication Within your NI DNET application the ncOpenDnet IO function configures the timing for I O connections in which your application communicates as master As you read this section you might want to refer to the description of the ncopenDnet 10 function in the NI DNET Programmer Reference Manual Expected Packet Rate National Instruments Each DeviceNet I O connection contains an attribute called the expected packet rate which specifies the expected rate in milliseconds of messages packets for the I O connection For NI DNET you use the ExpPacketRate parameter of the ncopenDnet10 function to configure the expected packet rate After you start communication the embedded microprocessor on your National Instruments DeviceNet interface transmits messages at the ExpPacketRate This means that after the I O connection is configured your NI DNET application does not need to be concerned with the timing of messages on the DeviceNet network 4 1 NI DNET User Manual Chapter 4 NI DNET Programming Technigues When you select an ExpPacketRate for an I O connection you must consider all I O connections in your system For example although you might be able to configure an ExpPacketRate of 3 ms for a single I O connection you cannot configure a
10. and select Change To Read Local For more information on local variables refer to the LabVIEW online reference If your application essentially accesses all DeviceNet input output data as a single image you would normally wait for read data to become available on one of the input connections such as a strobed I O connection read all input data execute your application code then write all output data The wait is important because it helps to synchronize your application with the overall DeviceNet network traffic In single loop applications such as this you normally set the Po11Mode parameter of ncOpenDnet Int f to Automatic or Scanned so that all poll command messages are sent out in quick succession Within a single loop application error handling is often done for the entire application as a whole In the C programming language this means that when an error is detected with any NI DNET object you display the error and exit the application In LabVIEW this means that you wire all error clusters of NI DNET VIS together If your application uses different control code for different DeviceNet devices you might want to split your application into multiple tasks You can easily write a multitasking application by creating a notification for the NI DNET Read Avail state This notification occurs when either input data is available to synchronize your code with each device s 4 16 ni com O National Instruments Chapter 4 NI DNET
11. components such as documentation and examples The NI CAN software components are available within the NI DNET installer Launch the setup exe program for the NI DNET installer in the same manner as your original installation CD or ni com download Within the installer select both NI DNET and NI CAN components in the feature tree When you right click a port in MAX and select Properties the resulting Interface selection uses the syntax CANx or DNETx based on your protocol selection Regardless of which protocol is selected the number x is the only relevant identifier with respect to NI CAN and NI DNET functions For example if you select DNETO as an interface in MAX you can run an NI DNET application that uses DNETO then you can run an NI CAN application that uses CANO Both applications refer to the same port and can run at different times but not simultaneously 1 8 ni com Hardware Overview Types of Hardware O National Instruments The National Instruments DeviceNet hardware includes the PCI CAN PX1 8461 and PCMCIA CAN The PCI CAN is software configurable and compliant with the PCI Local Bus Specification It features the National Instruments MITE bus interface chip that connects the card to the PCI I O bus With a PCI CAN you can make your PC compatible computer with PCI Local Bus slots communicate with and control DeviceNet devices The PXI 8461 is software configurable and compliant with
12. different classes of geometric shapes could include sguares circles and triangles Figure A 1 shows various classes and instances of geometric shapes Figure A 1 Glasses of Geometric Shapes AII sguares belong to the same class because they all have similar gualities such as four egual sides The term instance refers to a specific instance of a given class For example a blue sguare of four inches per side would be one instance of the class sguare and a red sguare of five inches per side would be another instance The term object is often used as a synonym for the term instance although in some contexts it might also refer to a class Each class defines a set of attributes which represent its externally visible characteristics The set of attributes defined by a class is common to all instances within that class For the class square attributes could include length of each side and color For the class circle attributes could include radius and color Each class also defines a set of services or methods which is used to perform an operation on an instance For the class square services could include resize rotate or change color A 3 NI DNET User Manual Appendix DeviceNet Overview Object Modeling in the DeviceNet Specification Figure A 2 illustrates the object modeling used within the DeviceNet Specification Application s Object s Parameter Identity
13. press Ctrl H to open the help window click on the NI DNET function and then follow the link The NI DNET software includes a full set of examples for LabVIEW These examples teach basic NI DNET programming as well as advanced topics The example help describes each example and includes a link you can use to open the VI The NI DNET example help is in Help Find Examples Hardware Input and Output DeviceNet 3 1 NI DNET User Manual Chapter 3 Developing Your Application LabWindows GVI Within LabWindows CVI the NI DNET function panel is located in Library NI DNET Like other LabWindows CVI function panels the NI DNET function panel provides help for each function and the ability to generate code The reference for each NI DNET function is provided in the NJ DNET Programmer Reference Manual You can access reference for each function directly from within the function panel The header file for NI DNET is nidnet h The library for NI DNET is nidnet lib The NI DNET software includes a full set of examples for LabWindows CVI The NI DNET examples are installed in the LabWindows CVI directory under samples nidnet Each example provides a complete LabWindows CVI project prj file A description of each example is provided in comments at the top of the c file When you compile your LabWindows CVI application for NI DNET it is automatically linked with nidnet 1ib the link library for LabWindows CVI When NI DNET is installed
14. 2 with MAX C 1 troubleshooting NI resources E 1 W Web resources E 1 ni com
15. 3 ms ExpPacketRate for 40 I O connections because DeviceNet s bandwidth capabilities cannot support 40 messages in a 3 ms time frame The following sections describe how to evaluate system considerations so that you can configure valid values for ExpPacketRate Strobed 1 0 For strobed I O connections the master broadcasts a single strobe command message to all strobed slaves Since all strobed I O connections transfer data at the rate of this single strobe command message the ExpPacketRate of each strobed I O connection must be set to the same value The common ExpPacketRate for all strobed I O connections should provide enough time for the strobe command and each strobed slave s response You must also allow time for other I O messages and explicit messages to occur in the ExpPacketRate time frame If you do not know the time needed let NI DNET calculate a safe value for you refer to the section Automatic EPR Feature later in this chapter Figure 4 1 shows a timing example for four strobed devices at MAC ID 9 11 12 and 13 Notice that since MAC ID 11 is slow to respond the ExpPacketRate is set to 20 ms to provide additional safety margin for other messages o o 8 E o t o E E 2 2 2 E S 8 2 E Q B Q Q E 8 a o o o o o o 2 2 2 2 2 g 2 a
16. DeviceNet devices refer to Appendix B Cabling Reguirements For connection to the network the PCI CAN PXI 8461 and PCMCIA CAN for DeviceNet provide combicon style pluggable screw terminals as reguired by the DeviceNet Specification Differences Between CAN Kits and DeviceNet Kits NI DNET User Manual National Instruments provides hardware software kits for both CAN and DeviceNet Since the CAN kits apply to a broad range of applications such as automotive testing the hardware in those kits offers a wide variety of options To ensure that the hardware product operates properly on a DeviceNet network we recommend that you purchase DeviceNet kits only The card provided in your DeviceNet kit can be used with both NI DNET and NI CAN software Hardware in CAN kits 15 referenced as Series 2 Hardware in DeviceNet kits is referenced as Series 1 Series 2 CAN cards cannot be used with the NI DNET software NI CAN only The features of Series 2 CAN cards are specifically designed for CAN applications and provide no distinct advantages for DeviceNet For more information on Series 2 hardware refer to the hardware overview in the NI CAN Hardware and Software Manual Hardware in CAN kits offers 1 port and 2 port variants NI DNET operates on one port only If you use NI DNET on a 2 port Series 1 CAN card only the top port can be used Hardware in CAN kits offer special transceivers physical layer such as Low Speed Fault Tolerant L
17. DeviceNet hardware can also be used for low level access to CAN messages using the NI CAN software NI CAN is intended primarily for applications that reguire direct access to CAN messages such as test applications for automotive non DeviceNet networks When 1 7 NI DNET User Manual Chapter 1 NI DNET Software Overview NI DNET User Manual connecting to a DeviceNet network the NI CAN capabilities are useful for the following applications e Low level monitoring of CAN messages to determine conformance to DeviceNet specifications Implementation of sections of the DeviceNet Specification yourself such as custom configuration tools NI CAN uses the same software infrastructure as NI DNET so both APIs can be used with the same CAN card The general rule is that each CAN card can only be used for one API at a time Use of NI DNET is restricted to port 1 top port of Series 1 CAN cards For more information on hardware provided in CAN kits refer to Chapter 2 NI DNET Hardware Overview You can view each CAN card in MAX with either DeviceNet or CAN features To change the view of a CAN card in MAX right click the card and select Protocol In this dialog you can select either DeviceNet for NI DNET default or CAN for NI CAN When the CAN protocol is selected you can access CAN tools in MAX such as the Bus Monitor tool that displays CAN messages in their raw form In order to develop NI CAN applications you must install NI CAN
18. LabWindows CVI you can use front panel controls to index through this array and update configurations as needed In your code write a For loop to index through the array and call ncOpenDnet IO once for each array entry This simplifies your code because it does not contain a long list of sequential open calls but instead all open calls are combined into a concise loop National Instruments 4 15 NI DNET User Manual Chapter 4 NI DNET Programming Technigues Object Handles Main Loop NI DNET User Manual If you use an array to store configuration parameters for ncOpenDnet10 you can use this same scheme to store the ObjHan le returned by ncOpenDnet10 Within the For loop used for ncopenDnet IO you can store the resulting ObjHand1e into an array of object handles Throughout your code you can index into this array to obtain the appropriate object handle Using an array of object handles is particularly useful in the Lab VIEW programming environment because it eliminates confusing routing of individual object handle wires For applications with only a few object handles another useful technique for LabVIEW is to store each object handle in an indicator then create a local variable for each call that uses the handle To create the indicator right click on the ObjHandle out terminal and select Create Indicator To create a local variable right click on the indicator select Create Local Variable right click on the local variable
19. NI DNET object using one of the three open functions ncOpenDnetExp1Msg ncOpenDnet Int f or ncOpenDnet IO The services for an NI DNET object are accomplished using the NI DNET functions which can be called directly from your programming environment such as Microsoft C C or LabVIEW The essential attributes of an NI DNET object are initialized using its open function you can access other attributes using ncGetDriverAttr or ncSetDriverAttr The attributes of NI DNET device driver objects are called driver attributes to differentiate them from actual attributes in remote DeviceNet devices For complete information on each NI DNET object including its driver attributes and supported functions services refer to your NI DNET Programmer Reference Manual National Instruments 1 5 NI DNET User Manual Chapter 1 NI DNET Software Overview Interface Object The Interface Object represents a DeviceNet interface physical DeviceNet port on your DeviceNet board Since this interface acts as a device on the DeviceNet network much like any other device it is configured with its own MAC ID and baud rate Use the Interface Object to do the following e Configure NI DNET settings that apply to the entire interface e Start and stop communication for all NI DNET objects associated with the interface Explicit Messaging Object 1 0 Object NI DNET User Manual The Explicit Messaging Object represents an explicit messaging connection
20. O After you start communication you can use the ncGetDriverAttr function to determine the value calculated for ExpPacketRate From that value you can then experiment with other ExpPacketRate configurations using PollMode of Scanned or Individual The following information is used by NI DNET to calculate a safe EPR e NI DNET assumes that it is the only master in your DeviceNet system e The BaudRate parameter of ncOpenDnetInt determines the time taken for each message e The InputLength and OutputLength parameters of each ncOpenDnetIO determine the time needed for each I O message NI DNET assumes that each strobed polled I O device can respond to its command within 2 ms NI DNET sets aside a fixed amount of time for explicit messages This time depends on the baud rate Using 1 0 Data in Your Application NI DNET User Manual Appendix A DeviceNet Overview explains that the data transferred to and from a DeviceNet device on an I O connection is usually processed by an Assembly Object within the slave device Input assemblies represent the data received by NI DNET from a remote device and output assemblies represent data that NI DNET transmits to a remote device To use a device s I O data within your application you need to understand the contents of its input and output assemblies You can find this information in the following places e Printed documentation provided by the device s vendor e
21. Object Assembly Object Message Router DeviceNet Object Messaging Connection Objects DeviceNet Network Figure A 2 Object Modeling Used in DeviceNet Specification Every DeviceNet device contains at least one instance instance one of the Identity Object The Identity Object instance defines attributes which describe the device including the device s vendor product name and serial number The Identity Object also defines services which apply to the entire device For example if you use the Reset service on instance one of the Identity Object the device resets to its power on state NI DNET User Manual A 4 ni com Appendix A DeviceNet Overview Another class of object contained in every DeviceNet device 15 the Connection Object Each instance of the Connection Object represents a communication path to one or more devices Attributes of each Connection Object instance include the maximum number of bytes produced on the connection the maximum number of bytes consumed and the expected rate at which data is transferred In Figure A 2 the term Application Object s refers to objects within the device which are used to perform its fundamental behavior For example within a photoelectric sensor an instance of the Presence Sensing object an Application Object represents the physical photoelectric sensor hardware Within a position controller device an instance of the Position C
22. V and pins on the Combicon connector The jumper must be in this position for the DeviceNet interface to be compliant with the DeviceNet Specification If the DeviceNet interface is being used in a system where bus power is not available the jumper may be set in the INT position In this position the physical layer is powered by the host computer The physical layer is still optically isolated But under the settings the PCI CAN card is not compliant with the DeviceNet specification Figure B 5 shows how to configure your jumpers for internal or external power supplies INT EXT INT EXT 3 2 1 LT a Internal Power Mode b External Power Mode DeviceNet Figure B 5 Power Source Jumpers B 4 ni com Appendix Gabling Reguirements For port one of the PXI 8461 power is configured with jumper J5 The location of this jumper is shown in Figure B 6 Ld NATIONAL INSTRUMENTS CORP m ASSY185316A PXI Fa 9 1998 200500505 P umoo MM are 6 Ol OV BA 3 ORE s Ba a t aj ad gum MINI MITE OV B Ofan ges
23. com environment weee htm Dx RT ERI ais SEE HE RoHS GG AEA National Instruments Ah P7 m np E d f da ROHS KF National Instruments EI RoHS 1 ES ni com environment rohs china For information about China RoHS compliance go to ni com environment rohs china NI DNET User Manual D 4 ni com Technical Support and Professional Services O National Instruments Log in to your National Instruments ni com User Profile to get personalized access to your services Visit the following sections of ni com for technical support and professional services e Support Technical support at ni com support includes the following resources Self Help Technical Resources For answers and solutions visit ni com support for software drivers and updates a searchable KnowledgeBase product manuals step by step troubleshooting wizards thousands of example programs tutorials application notes instrument drivers and so on Registered users also receive access to the NI Discussion Forums at ni com forums NI Applications Engineers make sure every question submitted online receives an answer Standard Service Program Membership This program entitles members to direct access to NI Applications Engineers via phone and email for one to one technical support as well as exclusive access to eLearning training modules at ni com elearning All customers auto
24. for an error include lt windows h gt include nidnet h HINSTANCE NidnetLib NULL NidnetLib LoadLibrary nican dll if NidnetLib NULL return FALSE Error 3 4 ni com National Instruments Chapter 3 Developing Your Application Get the addresses for the NI DNET DLL functions you will use Your application must use Win32 Get ProcAddress function to get the addresses of the NI DNET functions your application needs For each NI DNET function used by your application you must define a direct entry prototype For the prototypes for each function exported by nican 11 refer to the NI DNET Programmer Reference Manual The following code fragment illustrates how to get the addresses of the ncOpenDnetIO ncCloseObject and ncReadDnet IO functions static NCTYPE STATUS NCFUNC PncOpenDnetIO NCTYPE STRING ObjName NCTYPE OBJH P ObjHandlePtr static NCTYPE STATUS NCFUNC PncCloseObject NCTYPE OBJH ObjHandle static NCTYPE STATUS NCFUNC PncReadDnetIO NCTYPE OBJH ObjHandle NCTYPE UINT32 SizeofData NCTYPE ANY P Data PncOpenDnetIO NCTYPE STATUS NCFUNC NCTYPE STRING NCTYPE OBJH P GetProcAddress NidnetLib LPCSTR ncOpenDnetIO PncCloseObject NCTYPE STATUS NCFUNC NCTYPE OBJH GetProcAddress NidnetLib LPCSTR ncCloseObject PncRead NCTYPE STATUS NCFUNC NCTYPE OBJH NCTYPE UINT32 NCTYPE ANY P GetProcAdd
25. in your code then link with the nidnetms 1ib library file For C applications files with a c extension include the header file by adding a tinclude to the beginning of your code as in tinclude nidnet h For C applications files with cpp extension define cplusplus before including the header such as define _cplusplus include nidnet h The cpluspius define enables the transition from C to the C language NI DNET functions The reference for each NI DNET function is provided in the NJ DNET Programmer Reference Manual which you can open from Start All Programs National Instruments NI DNET You can find examples for Visual C in the examples subfolder of the MS Visual c folder Each example is in a separate folder A c file with the same name as the example contains a description the example in comments at the top of the code At the command prompt after setting MSVC environment variables such as with MS vcvars32 bat you can build each example using a command such as cl I singin c Xnidnetms lib The NI DNET software supports Borland version 5 or later The header file and library for Borland are in the Borland C folder of the NI DNET folder The typical path to this folder is Program Files National Instruments NNI DNET Borland C To use NI DNET include the nidnet h header file in your code then link with the nidnetbo 1ib library file 3 3 NI DNET User Manual Chap
26. interrupts with other devices in the system Does the CAN card provide power to the CAN bus No To provide power to the CAN bus you need an external power supply C 3 NI DNET User Manual Appendix Troubleshooting and Common Questions Can I use multiple PCMCIA cards in one computer Yes but make sure there are enough free resources available Unlike PCI or PXI CAN cards PCMCIA CAN cards cannot share resources such as IROs with other devices Why are some components left after the NI DNET software is uninstalled The uninstall program removes only items that the installation program installed If you add anything to a directory that was created by the installation program the uninstall program does not delete that directory because the directory is not empty after the uninstallation You must remove any remaining components yourself NI DNET User Manual C 4 ni com Hardware Specifications This appendix describes the physical characteristics of the DeviceNet hardware along with the recommended operating conditions PCI CAN Series Dimensions Power requirement I O connector e i s Operating environment Ambient temperature Relative humidity Storage environment Ambient temperature Relative humidity PCMCIA CAN Series Dimensions eeeeeennme Power requirement Operating environment Ambient temperature Relative h
27. of the value of its output bit each strobed slave responds to the command message by sending an individual strobe message back to the master The slave s strobe response contains from 0 to 8 bytes of input data Figure A 4 shows an example of four strobed slave devices Output data Input data Slave MAC ID 9 4 Byte Strobe Response ea Master MAC ID 1 oppose a T 1 Byte Strobe Response _____ 6 Byte Strobe 2 Byte Strobe Response Response Slave Slave Slave MAC ID 11 MAC ID 12 MAC ID 13 8 Byte Strobe Command 12 11 12 13 es eo es Used Used by 9 by 12 Used Used by11 by13 O National Instruments Figure 4 Strobed 1 0 Example A 9 NI DNET User Manual Appendix A DeviceNet Overview Change of State and Cyclic 1 0 NI DNET User Manual The change of state COS and cyclic I O connections both use the same underlying communication mechanisms Both transmit data at a fixed interval called the expected packet rate EPR Since COS and cyclic T O connections use the same messaging on the DeviceNet network they are often referred to as a single I O connection called COS cyclic I O The cyclic I O connection enables a slave device to send input data to its master at the configured EPR interval You normally configure the EPR to be consiste
28. the CAN hardware using the installed NI CAN or NI DNET software If you get this error shut down your computer restart it and run the Self Test again C 2 ni com Appendix Troubleshooting and Common Ouestions If the error continues after restart uninstall NI CAN and NI DNET and then reinstall NI CAN Hardware Problem Encountered This error occurs if the Self Test detects a defect in the CAN hardware If you get this error write down the numeric code shown with the error and contact National Instruments Common Questions National Instruments How can I determine which version of the NI DNET software is installed on my system Within MAX open the Software branch and select NI DNET The version is displayed in the right pane of MAX How many CAN cards can I configure for use with my NI DNET software The NI DNET software can be configured to communicate with up to 32 CAN cards on all supported operating systems Which CAN hardware for DeviceNet does the NI DNET software support The NI DNET software for supports Port 1 Series 1 High Speed HS cards Although you can use 2 port CAN cards only the top port can be used with NI DNET For more information refer to Chapter 2 NI DNET Hardware Overview Does NI DNET support 2 port CAN cards Refer to the previous question Are interrupts required for the NI CAN cards Yes one interrupt per card is required However PCI and PXI CAN cards can share
29. the installation program checks to see which compatible C compiler you are using with LabWindows CVI Microsoft or Borland and copies an appropriate nidnet lib for that compiler Microsoft Visual Basic NI DNET User Manual To create an NI DNET application in Visual Basic add the nidnet bas file to your project This allows you to call any NI DNET function file from your code The nidnet bas file is located in the MS Visual Basic folder of the NI DNET folder The typical path to this folder is Program Files National Instruments NI DNET MS Visual Basic The reference for each NI DNET function is provided in NJ DNET Programmer Reference Manual which you can open from Start All Programs National Instruments NI DNET You can find examples for Visual Basic in the examples subfolder of the MS Visual Basic folder Each example is in a separate folder A vbp file with the same name as the example opens the Visual Basic project A description of the example is located in a Help form within the project 3 2 ni com Microsoft C C Borland C C O National Instruments Chapter 3 Developing Your Application The NI DNET software supports Microsoft Visual C C version 6 The header file and library for Visual C C 6 are in the MS Visual C folder of the NI DNET folder The typical path to this folder is Program Files National Instruments NNI DNETMMS Visual To use NI DNET include the nidnet h header file
30. to the Online Product Certification section 8 Note For EMC compliance operate this device with shielded cabling CE Compliance C This product meets the essential requirements of applicable European Directives as follows e 2006 95 EC Low Voltage Directive safety e 2004 108 EC Electromagnetic Compatibility Directive EMC National Instruments D 3 NI DNET User Manual Appendix D Hardware Specifications Online Product Certification To obtain product certifications and the Declaration of Conformity DoC for this product visit ni com certification search by model number or product line and click the appropriate link in the Certification column Environmental Management NI is committed to designing and manufacturing products in an environmentally responsible manner NI recognizes that eliminating certain hazardous substances from our products is beneficial to the environment and to NI customers For additional environmental information refer to the NI and the Environment Web page at ni com environment This page contains the environmental regulations and directives with which NI complies as well as other environmental information not included in this document Waste Electrical and Electronic Equipment WEEE EU Customers At the end of their life cycle all products must be sent to a WEEE recycling center For more information about WEEE recycling centers and National Instruments WEEE initiatives visit ni
31. typically used for devices which provide both input and output data such as position controllers and modular I O devices Figure A 3 shows an example of four polled slave devices Output data Master Input data MAC ID 1 12 Byte Poll Command ___15 Byte Poll Response 6BytePollResponse 0 5 Byte Poll Command i 2 Byte Poll 5 Byte Poll 20 Byte Poll 3 Byte Poll i Command Response Command Response i Slave Slave Slave Slave MAC ID 9 MAC ID 11 MAC ID 12 MAC ID 13 Figure 3 Polled 1 0 Example NI DNET User Manual A 8 ni com Bit Strobed 1 0 Appendix A DeviceNet Overview The bit strobed I O connection is designed to move small amounts of input data from the slave to its master Strobed I O is typically used for simple sensors such as photoelectric sensors and limit switches Strobed I O is also called bit strobed I O since the master sends a 64 bit 8 byte message containing a single bit of output data for each strobed slave This strobe command request message is received by all slave devices simultaneously and can be used to trigger simultaneous measurements such as to take multiple photoelectric readings simultaneously When strobed slave receives the strobe command it uses the output data bit that corresponds to its own MAC ID for example the slave with MAC ID 5 uses bit 5 Regardless
32. 20 to 70 C 5 to 9596 noncondensing Tested in accordance with IEC 60068 2 1 IEC 60068 2 2 IEC 60068 2 56 30 g peak half sine 11 ms pulse Tested in accordance with IEC 60068 2 27 Test profile developed in accordance with MIL T 28800E 5 to 500 Hz 0 3 grms 5 to 500 Hz 2 4 grms Tested in accordance with IEC 60068 2 64 Nonoperating test profile developed in accordance with MIL T 28800E and MIL STD 810E Method 514 ni com Appendix D Hardware Specifications Port Characteristics BUS ctt ertet een 0 to 30 V 40 mA typical 100 mA maximum CAN H CAN L eee 8 to 18 V DC or peak CATI Safety This product meets the requirements of the following standards of safety for electrical equipment for measurement control and laboratory use e TEC 61010 1 EN 61010 1 e UL 61010 1 CSA 61010 1 8 Note For UL and other safety certifications refer to the product label or the Online Product Certification section Electromagnetic Compatibility This product meets the requirements of the following EMC standards for electrical equipment for measurement control and laboratory use e EN 61326 1 IEC 61326 1 Class A emissions Basic immunity 1 e EN 55011 CISPR 11 Group 1 Class A emissions e AS NZS CISPR 11 Group 1 Class A emissions e FCC 47 CFR Part 15B Class A emissions e CES 001 Class A emissions 8 Note For the standards applied to assess the EMC of this product refer
33. 30 Poll Response 17 Poll Response 14 Poll Response 20 0 ms NI DNET User Manual 5ms 10 ms 15ms 20 ms Figure 4 2 Scanned Polling Timing Example Background Polling Scanned polling can be less efficient when used with devices with significantly different response times or devices with significantly different rates of physical measurement In the example above Figure 4 2 consider what would happen if device 14 took 52 ms to respond and device 20 took 38 ms to respond In this case even though device 17 and device 30 respond well within 20 ms the common ExpPacketRate would need to be at least 52 ms This situation can often be avoided using a special case of scanned polling called background polling To configure background polling you first set the Po11Mode parameter of ncOpenDnetIntf to Scanned Then for each polled I O connection you configure ncOpenDnet10 with ConnectionType set to Po11 you must set ExpPacketRate to either a foreground rate or a background rate The foreground poll rate is the same as the common ExpPacketRate used for all strobed I O Devices in this group generally respond quickly to poll commands or have data that changes relatively quickly The background poll rate must be an exact multiple of the foreground poll rate Devices in this group generally respond slowly to poll commands or have data that changes relati
34. C ID represents its address on the DeviceNet network G 4 ni com master slave MB member method multi drop network interface network management utility network who NI DNET driver notification 0 object object oriented ODVA O National Instruments Glossary DeviceNet communication scheme in which a master device allocates connections to one or more slave devices and those slave devices can only communicate with the master and not one another Megabytes of memory Individual data value within a DeviceNet I O Assembly See service A physical connection in which multiple devices communicate with one another along a single cable A device s physical connection onto a network Utility used to manage configuration of DeviceNet devices A search of a DeviceNet network to determine information about its devices Device driver and or firmware that implement all the specifics of a National Instruments DeviceNet interface Within NI DNET an operating system mechanism that the NI DNET driver uses to communicate events to your application You can think of a notification of as an API function but in the opposite direction See instance A software design methodology in which classes instances attributes and methods are used to hide all of the details of a software entity that do not contribute to its essential characteristics Open DeviceNet Vendor s Association G 5 NI DNET User Manual Glossar
35. DeviceNet NI DNET User Manual June 2012 NATIONAL instruments Worldwide Technical Support and Product Information ni com Worldwide Offices Visit ni com niglobal to access the branch office Web sites which provide up to date contact information support phone numbers email addresses and current events National Instruments Corporate Headguarters 11500 North Mopac Expressway Austin Texas 78759 3504 USA Tel 512 683 0100 For further support information refer to the Technical Support and Professional Services appendix To comment on National Instruments documentation refer to the National Instruments Web site at ni com info and enter the Info Code feedback 1998 2012 National Instruments rights reserved Important Information Warranty The CAN DeviceNet Hardware is warranted against defects in materials and workmanship for a period of one year from the date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace eguipment that proves to be defective during the warranty period This warranty includes parts and labor The media on which you receive National Instruments software are warranted not to fail to execute programming instructions due to defects in materials and workmanship for a period of 90 days from date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace softwa
36. DeviceNet hardware right click the DeviceNet card then select Self test If the self test passes the card icon shows a checkmark If the self test fails the card icon shows an X mark and the Test Status in the right pane describes the problem Refer to Appendix C Troubleshooting and Common Questions for information about resolving hardware installation problems Configure DeviceNet Port The physical port of each DeviceNet card is listed under the card s name To configure software properties right click the port and select Properties NI DNET User Manual 1 2 ni com Chapter 1 NI DNET Software Overview In the Properties dialog you assign an interface name to the port such as DNETO DNETI The interface name identifies the physical port within NI DNET APIs Change Protocol To change the default protocol for the DeviceNet CAN card right click the card and select Protocol In this dialog you can select either DeviceNet for NI DNET default or CAN for NI CAN For more information refer to the section Using NI CAN with NI DNET LabVIEW Real Time RT Configuration LabVIEW Real Time RT combines easy to use LabVIEW programming with the power of real time systems When you use a National Instruments PXI controller as a LabVIEW RT system you can install a PXI DeviceNet card and use the NI DNET APIs to develop real time applications For example you can control a network of DeviceNet devices as a master and write your c
37. E idee ed dtd de eet tee iei ed 3 3 Other Programming Languages eeseeeeeeeeenen eene 3 4 Programming Model for NI DNET Applications eee 3 6 Step T Open Objects eese etn ebd ite tee edes 3 8 Step 2 Start Communication ssessesseseeseeeeeeneen rennen en eere en eene 3 8 Step 3 Run Your DeviceNet Application esee 3 9 Addition of Slave Connections after Communication Start 3 10 Step 4 Stop Communication sissisota i a aia 3 10 Step 5 Close Objects eue ete e quet tede ees ien 3 10 Multiple Applications on the Same Interface sess 3 10 Checking Status in LabVIEW eet tit eee e re Redes dre 3 11 Checking Status in C C and Visual Basic essere 3 12 Chapter 4 NI DNET Programming Techniques Configuring I O Connections esee ren ener eene nne 4 1 Expected Packet Rate uie eti opa e e Ten 4 1 Strobed e Ep een 4 2 Polled 1 O etta tems 4 3 Cyclic VO xian sei ida 4 6 Change of State COS T O siosana ioci eiai isai a 4 7 Automatic ttd Maat Re enter EE i 4 7 Using I O Data in Your Application esee 4 8 Accessing I O Members in LabVIEW eese 4 10 Accessing I O Members in eaan 4 11 Using Explicit Messaging Services eene eene 4 12 Get and S
38. ENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA PROFITS USE OF PRODUCTS OR INCIDENTAL OR CONSEQUENTIAL DAMAGES EVEN IF ADVISED OF THE POSSIBILITY THEREOF This limitation of the liability of National Instruments will apply regardless of the form of action whether in contract or tort including negligence Any action against National Instruments must be brought within one year after the cause of action accrues National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control The warranty provided herein does not cover damages defects malfunctions or service failures caused by owner s failure to follow the National Instruments installation operation or maintenance instructions owner s modification of the product owner s abuse misuse or negligent acts and power failure or surges fire flood accident actions of third parties or other events outside reasonable control Copyright Under the copyright laws this publication may not be reproduced or transmitted in any form electronic or mechanical including photocopying recording storing in an information retrieval system or translating in whole or in part without the prior written consent of National Instruments Corporation National Instruments respects the intellectual property of others and we ask our users to do the same NI software is protected by copyright and other intellectual property laws Where NI software
39. I DNET Explicit Messaging Object represents an explicit messaging connection to a remote DeviceNet device You use ncOpenDnetExp1Msg to configure and open an NI DNET Explicit Messaging Object The following sections describe how to use the Explicit Messaging Object 4 12 ni com Chapter 4 NI DNET Programming Technigues Get and Set Attributes in a Remote DeviceNet Device The two most commonly used DeviceNet explicit messages are the Get Attribute Single service and the Set Attribute Single service These services are used to get or setthe value of an attribute contained in a remote device The easiest way to execute the Get Attribute Single service on a remote device is to use the NI DNET ncGetDnetattribute function The easiest way to execute the Set Attribute Single service on a remote device is touse the NI DNET ncSetDnetattribute function For a given attribute of a DeviceNet device you need the following information to use the ncGetDnetattribute orncSetDnetattribute function e class and instance identifiers for the object in which the attribute is located The attribute identifier e The attribute s DeviceNet data type You can normally find this information from the object specifications contained in the DeviceNet Specification but many DeviceNet device vendors also provide this information in the device s documentation For the C programming language the attribute s DeviceNet data type determines the corresp
40. MAC IDs for smaller ExpPacketRate values Since smaller MAC IDs in DeviceNet usually gain access to the network before larger MAC IDs this helps to ensure that smaller rates can be maintained during bursts of increased traffic Figure 4 4 shows an individual polling example MAC ID 3 is polled every 10 ms MAC ID 10 every 35 ms MAC ID 12 every 100 ms and MAC ID 13 every 700 ms Only the poll commands are shown not poll responses or other messages Poll Cmd 3 Poll Cmd 10 Poll Cmd 3 Poll Cmd 3 Poll Cmd 12 Poll Cmd 3 Poll Cmd 3 Poll Cmd 10 Poll Cmd 3 Poll Cmd 13 Poll Cmd 3 Poll Cmd 3 Poll Cmd 10 Poll Cmd 3 0 ms 20 ms 40 ms 60 ms 80 ms NI DNET User Manual Figure 4 4 Individual Polling Timing Example Cyclic 1 0 Cyclic I O connections essentially use the same timing scheme as individually polled I O connections Each cyclic I O connection sends its data at the configured ExpPacketRate The main difference is that cyclic I O data is transferred from slave to master rather than from master to slave In the DeviceNet Specification a poll command message is exactly the same as a cyclic output message master to slave data Since cyclic data from master to slave can be handled using individual polling cyclic I O connections are more commonly used for input data from slave to master For NI DNET this
41. Net Specification defines two types of I O connections master slave and peer to peer In master slave I O connections a master device uses an I O connection to communicate with one or more slave devices and those slave devices can only communicate with the master and not one another In peer to peer I O connections each device on the network can communicate as a peer and communication paths between peer devices are established as needed The NI DNET software currently supports only master slave I O connections because the procedure used to establish these I O connections is more well defined For this reason almost all existing DeviceNet devices only implement master slave I O connections A 7 NI DNET User Manual Appendix DeviceNet Overview Polled 1 0 The DeviceNet Specification defines four types of master slave T O connections polled bit strobed change of state COS and cyclic A slave device can support at most one polled one strobed and one COS or cyclic connection COS and cyclic connections cannot be used simultaneously The polled I O connection uses a request response scheme for each device The master sends a poll command request message to the slave device with any amount of output data The slave then sends a poll response message back to the master with any amount of input data The poll command response messages are handled individually for each slave which supports polled I O connections Polled I O is
42. Object if it is not acceptable to send output data of all zeros call ncWriteDnet10 to provide valid output values for the initial transmission e For an I O Object if your application is multitasking call the ncCreateNotification function with the DesiredState parameter set to Read Available This notifies your application when new input data is received from the remote device e For any NI DNET object if any of the Driver attributes needs to be changed call ncSetDriverAttr with the attribute Id and attribute value The ncSetDriverattr function cannot be called after the communication has started NI DNET User Manual 3 8 ni com Chapter 3 Developing Your Application Step 3 Run Your DeviceNet Application After you open your NI DNET objects and start communication you are ready to interact with the DeviceNet network Complete the following steps with an I O Object 1 4 Call the ncwriteDnetIO function to write output data for subsequent transmission on the DeviceNet network Call the ncWaitForState function with the DesiredState parameter set to Read Available This function waits for output data to be transmitted and for new input data to be received If your application is multitasking you might have other tasks to do in your application while you wait for new input data If so use the ncCreateNotification function instead of ncWaitForState refer to Step 2 Start Communication Call the ncReadDnet 10 function to
43. Programming Technigues VO messages or an error occurs In the programming language you create this notification callback using the ncCreateNotification function In LabVIEW you use the ncWaitForState function In multiple loop applications such as this you normally set the Po11Mode parameter of ncOpenDnetIntf to Individual so that each poll command message can be sent out at its own individual rate Within a multiple loop application error handling is done separately for each task In the C programming language this means that when an error is detected you handle it for the appropriate task but you do not exit the application In LabVIEW this means that you only wire the error clusters of NI DNET VIs that apply to each task and thus you write different sub diagrams that are not wired together in any way 4 17 NI DNET User Manual DeviceNet Overview This appendix gives an overview of DeviceNet History of DeviceNet National Instruments The Controller Area Network CAN was developed in the early 1980s by Bosch a leading automotive eguipment supplier CAN was developed to overcome the limitations of conventional automotive wiring harnesses CAN connects devices such as engine controllers anti lock brake controllers and various sensors and actuators on a common serial bus By using a common pair of signal wires any device on a CAN network can communicate with any other device As CAN implementations became wi
44. S and Single Wire SW Hardware in CAN kits also offer the option to power the transceiver from the card not the network These transceivers cannot be used with DeviceNet Only High Speed HS transceivers comply with the DeviceNet specification Hardware in CAN kits use the DB 9 D SUB connector Hardware in DeviceNet kits use the combicon style connector from the DeviceNet specification 2 2 ni com Developing Your Application This chapter explains how to develop an application using the NI DNET functions Accessing NI DNET from your Programming Environment LabVIEW National Instruments Applications can access the NI DNET driver software by using either LabVIEW LabWindows CVI Microsoft Visual Borland C C or Visual Basic If you are using any other development environment you must access the DNET library directly Each of these language interface techniques is summarized below For applications written in LabVIEW NI DNET provides a complete function library front panel controls and examples NI DNET functions and controls are available in the LabVIEW palettes In LabVIEW 7 1 or later the NI DNET palette is located within the top level NI Measurements palette In earlier LabVIEW versions the NI DNET palette is located at the top level The reference for each NI DNET function is provided in the NJ DNET Programmer Reference Manual To access the reference for a function from within LabVIEW
45. This problem can be prevented if you increase the MAC ID of the frequently changing COS I O device If the COS device has a higher MAC ID than other devices it cannot preclude their I O messages You can also prevent back to back COS I O messages if you set the InhibitTimer driver attribute using ncSetDriverAttr After transmitting COS data the I O connection must wait InhibitTimer before it can transmit COS data again A reasonable value for InhibitTimer would be the smallest ExpPacketRate of an I O connection with a larger MAC ID than the COS I O device Automatic EPR Feature For cyclic I O connections a valid ExpPacketRate is required for your call to ncopenDnet IO For COS I O connections a nonzero ExpPacketRate is recommended for your call to ncOpenDnet10 but can be set to a large value National Instruments 4 7 NI DNET User Manual Chapter 4 NI DNET Programming Technigues For strobed and polled I O connections determination of a valid ExpPacketRate can be somewhat complex If you have trouble estimating an ExpPacketRate value for strobed polled I O set the PollMode parameter of your initial call to ncOpenDnet Int f to Automatic When you use this automatic EPR feature the ExpPacketRate parameter of ncOpenDnet IO is ignored for strobed polled I O ConnectionType of Strobe or Po11 and NI DNET calculates a safe EPR value for you This automatic EPR is the same for all strobed and polled I O connections scanned I
46. an enable only one notification or wait through the ncCreateNotification or ncWaitForState functions for an object no matter how many handles you have opened for that 3 10 ni com Chapter 3 Developing Your Application particular object For example if you are running two copies of the SingleDevice example on the same interface with the same connection types the notification triggers in only one application at a time The synchronization of events and the protection of the object I O data is the responsibility of the application developer Similarly the application performance might change based on the number of objects open and the frequency of API calls made in each application For example several calls to ncGetDnetAttribute in one application might slow down another application running on the same interface To ensure proper clean up of all the objects each open call to an object should be matched by a close call to the same object and each call to ncOperateDnetIntf with NC OP START code should be matched by a call to the same function with NC OP STOP code If you use two different applications on the same interface and open I O connections to different devices you must set Po11Mode to either Scanned or Individual You cannot use PollMode of Automatic because that requires all I O connections to be open prior to the first start of communication Checking Status in LabVIEW National Instruments For applications w
47. bit transmission rates Detailed cable length requirements can be found in the DeviceNet Specification Table B 2 lists the DeviceNet cable length specifications Table B 2 DeviceNet Cable Length Specifications Drop Length Drop Length Baud Rate Trunk Length Maximum Cumulative 500 kb s 100 m 328 ft 6 m 20 ft 39 m 128 ft 250 kb s 250 m 820 ft 6 m 20 ft 78 m 256 ft 125 kb s 500 m 1640 ft 6m 20 ft 156 m 512 ft Maximum Number of Devices The maximum number of devices that you can connect to a DeviceNet port depends on the electrical characteristics of the devices on the network If all of the devices on the network meet the DeviceNet specifications 64 devices may be connected to the network NI DNET User Manual B 6 ni com Appendix Gabling Reguirements Cable Termination The pair of signal wires CAN H and CAN L constitutes a transmission line If the transmission line is not terminated each signal change on the line causes reflections that may cause communication failures Because communication flows both ways on the DeviceNet bus DeviceNet requires that both ends of the cable be terminated However this requirement does not mean that every device should have a termination resistor If multiple devices are placed along the cable only the devices on the ends of the cable should have termination resistors Refer to Figure B 7 for an example of where termination resisto
48. cation and the actual attributes are documented in the individual object specifications Attribute documentation includes the attribute s DeviceNet data type and a complete explanation of its meaning As an example of I O assembly documentation consider the standard AC Drive device profile For this device profile the DeviceNet Specification defines an output assembly called Basic Speed Control Output Assembly Object instance 20 This output assembly is used to start stop forward motion at a given speed and to reset faults in the device The bytes of this output assembly are shown in Figure 4 6 and the attribute mapping is shown in Table 4 1 Byte Bit 7 0 0 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 0 0 0 0 Fault Reset 0 Run Fwd 0 0 0 0 0 0 0 Speed Reference Low Byte Speed Reference High Byte National Instruments Figure 4 6 AC Drive Output Assembly Instance 20 4 9 NI DNET User Manual Chapter 4 NI DNET Programming Technigues Table 4 1 Attribute Mapping for Basic Speed Control Output Assembly Member Class Attribute Name Name Class ID Instance ID Name Attribute ID Run Control 29 hex 1 Runl 3 Fwd Supervisor Fault Control 29 hex 1 FaultRst 12 Reset Supervisor Speed AC DC 2A hex 1 SpeedRef 8 Reference Drive By consulting the specifications for the Control Supervisor object and the AC DC Drive object you can determine that the DeviceNet data type for Ru
49. ction in which the master broadcasts a single strobe command to all strobed slaves then receives a strobe response from each strobed slave Controller Area Network Master slave I O connection which is similar to cyclic I O but data can be sent when a change in the data is detected A classification of things with similar qualities In explicit messaging connections the client is the device requesting execution of the service Services defined by the DeviceNet specification such that they are largely interoperable An association between two or more devices on a network that describes when and how data is transferred A device that receives data from sensors and sends data to actuators to hold One or more external real world variables at a certain level or condition A thermostat is a simple example of a controller See change of state I O Master slave I O connection in which the slave or master sends data at a fixed interval G 2 ni com D DC device device network device profiles direct entry DLL driver attributes EDS expected packet rate Explicit messaging connection FCC ft FTP National Instruments Glossary direct current A physical assembly linked to a communication line cable capable of communicating across the network according to a protocol specification Multi drop digital communication network for sensors actuators and controllers DeviceNet specifications wh
50. despread throughout the automotive industry CAN was standardized internationally as ISO 11898 and major semiconductor manufacturers such as Intel Motorola and Philips began producing CAN chips With these developments many manufacturers of industrial automation equipment began to consider other applications of CAN technology Automotive and industrial device networks showed many similarities including the transition away from dedicated signal lines low cost resistance to harsh environments and excellent real time capabilities In response to these similarities Allen Bradley developed DeviceNet an industrial networking protocol based on CAN DeviceNet built on CAN s communication facilities to provide higher level features which allow industrial devices from different vendors to operate on the same network Soon after DeviceNet was developed Allen Bradley transferred the specification to an independent organization called the Open DeviceNet Vendor s Association ODVA ODVA formally manages the DeviceNet Specification and provides services to facilitate development of DeviceNet devices and tools by various vendors Due in large part to the efforts of ODVA hundreds of different vendors now provide DeviceNet products for a wide range of applications A 1 NI DNET User Manual Appendix DeviceNet Overview Physical Characteristics of DeviceNet The following list summarizes the physical characteristics of DeviceNet Trunklin
51. e dropline cabling main trunk cable with a drop cable for each device e Selectable baud rates of 125 250 and 500 Table A 1 DeviceNet Baud Rates and Wiring Lengths Baud Trunk Drop Length Drop Length Rate Length Maximum Cumulative 125 Kb s 500 m 1640 ft 6 m 20 ft 156 m 512 ft 250 Kb s 250m 820 ft 6 m 20 ft 78 m 256 ft 500 Kb s 100 m 328 ft 6 m 20 ft 39 m 128 ft e Support for up to 64 devices each device identifies itself using a MAC ID Media Access Control Identifier from 0 63 e Device removal insertion without severing the network e Simultaneous support for both network powered and self powered devices e Various connector styles For complete information on how to connect your National Instruments hardware onto the DeviceNet network refer to your getting started manual General Object Modeling Concepts The DeviceNet Specification uses object oriented modeling to describe the behavior of different components in a device how those components relate to one another and how network communication takes place The following paragraphs briefly describe object oriented modeling and how these concepts are used within the DeviceNet Specification NI DNET User Manual A 2 ni com National Instruments Appendix A DeviceNet Overview In object oriented terminology a classification of components with similar gualities is called a class For example
52. es Since these two services are used often NI DNET provides functions for these services ncGetDnetAttribute and ncSetDnetAttribute Other services defined by DeviceNet are used less often For these services NI DNET provides general purpose functions to send an explicit message request ncWriteDnetExplMsg and receive an explicit message response ncReadDnetExp1Msg These NI DNET functions use parameters which are similar to the explicit message request response listed above For more information on DeviceNet common services other than Get Set Attribute Single refer to the DeviceNet Specification 1 0 Connections National Instruments In addition to explicit messaging connections DeviceNet devices provide another type of Connection Object called an I O connection I O connections provide a communication path for the exchange of physical input output sensor actuator data as well as other control oriented data I O connections are useful for transferring data at regular intervals Since many DeviceNet devices do not begin their normal operation until an I O connection is established explicit messaging is often used for configuration and initialization For example for a device with an analog input the I O connection is normally used to read the analog input measurement and explicit messages are used for configuration such as setting the measurement range and units such as 10 to 10 V versus 4 to 20 mA The Device
53. et Attributes in a Remote DeviceNet Device 4 13 Other Explicit Messaging Services iieeteenrtnteeeeees 4 14 Handling Multiple Devices rtt 4 15 Config fatlOn ccs ni D ERR E E ERU ERA AERE 4 15 Object Handles ee cet Reit 4 16 E 4 16 Appendix A DeviceNet Overview History of DeVIGENEL dU eme rre te ete E PER EY kaudu 1 Physical Characteristics of DeviceNet en eee 2 General Object Modeling Concepts iitiiereereeeeeeneeneenneeneeenenteeenenneeeneeneeee A 2 Object Modeling in the DeviceNet Specification sese A 4 Explicit Messaging Connections eese enne ener A 5 I O Connections x coe tette dae ne pf teen e epe tpe e edu ten 7 Assembly OHJEGES o Et OO ette Me t e A 12 NI DNET User Manual vi ni com Gontents Appendix B Cabling Requirements Connector Pinouts 13544 dn tete t tede dp teo Hi RO d ete petis B 1 Power Supply Information for the DeviceNet Ports B 3 Cable Specifications neget eee e ei nii e n Epl B 6 Cable Lengths wii niet nte oe e m e B 6 Maximum Number of Devices ieiirereteeereeeeeneoenennesenennesenenneeeneeteeenenneee B 6 Cable Termination 2 23 sd ie ede et e ei ripe ER B 7 Cabling Example 2 ueneno eue B 8 Appendix C Troubleshoot
54. fication Figure B 1 shows the pinout for this connector 1 V 3 Shield 5 V 2 CAN L 4 CAN H Figure B 1 Pinout for 5 Pin Combicon Style Pluggable Screw Terminal CAN Hand CAN L are signal lines that carry the data on the DeviceNet network These signals should be connected using twisted pair cable The V and V signals supply power to the DeviceNet physical layer Refer to Power Supply Information for the DeviceNet Ports for more information Shield is for the cable shield which must be connected B 1 NI DNET User Manual Appendix Cabling Requirements NI DNET User Manual Figure B 2 shows the end of a PCMCIA CAN bus powered cable The arrow points to pin 1 of the 5 pin screw terminal block of the signals on the 5 pin Combicon style pluggable screw terminal are connected directly to the corresponding pins on the 9 pin D SUB following the pinout in Figure B 3 Figure B 2 PCMCIA CAN Bus Powered Cable The 9 pin D SUB follows the pinout recommended by CiA Draft Standard 102 Figure B 3 shows the pinout for this connector No Connection Optional Ground V CAN L CAN H y No Connection No Connection V Shield Figure B 3 Pinout for 9 Pin D SUB Connector B 2 ni com Appendix Gabling Reguirements Power Supply Information for the DeviceNet Ports The bus must supply power to each DeviceNet port The bus power supply should be a DC power supply with a
55. he value of an external real world variable In the context of device networks actuators are devices that receive their primary data value from over the network examples include valves and motor starters Also known as final control element ANSI American National Standards Institute Application A collection of functions used by a user application to access hardware Programming Interface APD ASCII Assembly Object attribute automatic polling National Instruments Within NI DNET you use API functions to make calls into the NI DNET driver American Standard Code for Information Exchange Objects in DeviceNet devices which route I O message contents to from individual attributes in the device The externally visible qualities of an object for example an instance square of class Geometric Shapes could have the attributes length of sides and color with the values 4 in and blue A polled I O mode in which NI DNET automatically determines an appropriate scanned polling rate for your DeviceNet system G 1 NI DNET User Manual Glossary b background polling bit strobed O change of state I O class client common services connection controller COS I O cyclic I O NI DNET User Manual Bits A polled I O communication scheme in which all polled slaves are grouped into two different communication rates a foreground rate and a slower background rate Master slave I O conne
56. ht click the DeviceNet interface such as DNETO in MAX and select Analyzer 1 4 ni com Chapter 1 NI DNET Software Overview NI 1 0 Trace This tool monitors function calls to the NI DNET APIS This tool helps in debugging programming problems in your application To launch this tool open the Software branch of the MAX Configuration tree right click NI I O Trace and select Launch NI I O Trace NI DNET Objects The NI DNET software like the DeviceNet Specification uses object oriented concepts to represent components in the DeviceNet system for more information about object oriented concepts in the DeviceNet Specification refer to Appendix A DeviceNet Overview However whereas in the DeviceNet Specification objects represent a multitude of components in DeviceNet devices NI DNET objects represent components of the Windows device driver software The NI DNET device driver objects do not correspond directly to objects contained in remote devices To facilitate access to the DeviceNet network the NI DNET objects provide a more concise representation of various objects defined in the DeviceNet Specification Much like any other object oriented system NI DNET device driver objects use the concepts of class instance attribute and service to describe their features The NI DNET device driver software provides three classes of objects Interface Objects Explicit Messaging Objects and I O Objects You can open an instance of an
57. ication Write output data Wait for available input data Read input data Get or Set DeviceNet Attribute Open Close any new I O or EM connection if the interface Po11Mode is not equal to NC POLL AUTO Stop communication 1 Close I O and EM objects 2 Close the Interface object End Figure 3 1 General Programming Steps for an NI DNET Application National Instruments 3 7 NI DNET User Manual Chapter 3 Developing Your Application Step 1 Open Objects Before you use an NI DNET object in your application you must configure and open it using either ncOpenDnetIntf ncOpenDnetExplMsg or ncOpenDnetIO These open functions return a handle for use in all subsequent NI DNET calls for that object The ncOpenDnet Int f function configures and opens an Interface Object Your NI DNET application uses this Interface Object to start and stop communication The Interface Object must be the first NI DNET object opened by your application The ncOpenDnetExp1Msg function configures and opens an Explicit Messaging Object and the ncOpenDnet 10 function configures and opens an I O Object Step 2 Start Communication Start communication to initialize DeviceNet connections to remote devices Use the Interface Object to call the ncoperateDnetIntf function with the Opcode parameter set to Start The following optional steps can be done before you start communication e Foran I O
58. ich provide interoperability for devices of the same type Microsoft Win 32 functions used to directly access the functions of a Dynamic Link Library DLL Dynamic Link Library Attributes of the NI DNET driver software Electronic Data Sheet Text file that describes DeviceNet device features electronically The rate in milliseconds at which a DeviceNet connection is expected to transfer its data General purpose connection used for executing services on a particular object in a DeviceNet device Federal Communications Commission feet File transfer protocol G 3 NI DNET User Manual Glossary hex Hz T O connection in individual polling instance ISO KB L LabVIEW LED local MAC ID NI DNET User Manual Hexadecimal Hertz Connection used for exchange of physical input output sensor activator data as well as other control oriented data inches A polled I O communication scheme in which each polled slave communicates at its own individual rate A specific instance of a given class For example a blue square of 4 inches per side would be one instance of the class Squares International Standards Organization Kilobytes of memory Laboratory Virtual Instrument Engineering Workbench light emitting diode Within NI DNET anything that exists on the same host personal computer as the NI DNET driver meter Media access control layer identifier In DeviceNet a device s MA
59. igher level control algorithms can execute at the single common strobe poll ExpPacketRate The common ExpPacketRate for all strobed and polled I O connections should provide enough time for all strobe poll commands and each slave s response You must also allow time for other I O messages and explicit messages to occur in the ExpPacketRate time frame NI DNET provides two different methods you can use to configure scanned I O e Ifyou set the Pol1Mode parameter of ncOopenDnetIntf to Automatic NI DNET automatically calculates a valid common ExpPacketRate value for each strobed and polled I O connection When you use this scheme you do not need to specify a valid ExpPacketRate when you open your strobed polled I O connections For more information refer to the Automatic EPR Feature section later in this chapter 4 3 NI DNET User Manual Chapter 4 NI DNET Programming Technigues e fyousetthe Pol1Mode parameter of ncOpenDnetIntf to Scanned to configure scanned I O you must specify the exact same ExpPacketRate when you open each of your strobed polled I O connections Using this scheme you must determine a valid ExpPacketRate for your DeviceNet system Figure 4 2 shows a scanned polling example for four polled devices at MAC ID 14 17 20 and 30 The shaded areas indicate other message traffic such as the strobed I O messages shown in Figure 4 1 Poll Cmd 14 Poll Cmd 17 Poll Cmd 20 Poll Cmd 30 Poll Response
60. in MAX help pane If this help pane is not shown on the far right select the Show Hide button in the upper right View help for a dialog box by selecting the Help button in the window The following sections provide an overview of some common tasks you can perform within MAX National Instruments 1 1 NI DNET User Manual Chapter 1 NI DNET Software Overview Verify Installation of Your DeviceNet Hardware Within the Devices amp Interfaces branch of the MAX Configuration tree NI DeviceNet cards are listed along with other hardware in the local computer system as shown in Figure 1 1 DNETO Measurement amp Automation Explorer Col E Eile Edit View Tools Help 4 My System IN Configurator 0 Show Help 1 Data Neighborhood B Devices and Interfaces Attribute Value 4 WW NI CAN Devices Bl Interface Name DNETO Wi PCI CAN Bl Location Port 1 ED E Baud Rate 125 000 kBaud a Network Devices Bl interface MAC ID 0 3 Serial amp Parallel 44 Scales 50 Software ff IVI Drivers amp Remote Systems 7 7 4 Port Properties Figure 1 1 NI DNET Cards Listed in MAX 8 Note Each card s name uses the word CAN because the Controller Area Network is the communication protocol upon which DeviceNet is built If your NI DeviceNet hardware is not listed here MAX is not configured to search for new devices on startup To search for the new hardware press F5 To verify installation of your
61. ing and Common Questions Troubleshooting with the Measurement amp Automation Explorer MAX C 1 Troubleshooting Self Test Failures sese C 2 Common QuestIOnS uit etii e tree reget ete xen cet ride bene beste dose C 3 Appendix D Hardware Specifications Appendix E Technical Support and Professional Services Glossary Index National Instruments Vii NI DNET User Manual About This Manual This manual describes the basics of DeviceNet and explains how to develop an application program including reference to examples The user manual also contains hardware information How to Use the Manual Set Installation Guide CD Sleeve Software and Hardware Installation First Time Experienced NI DNET Users NI DNET Users NI DNET Application NI DNET User Manual Development Programmer and Examples 4 gt Reference Manual Function and Object cM E N Descriptions Use the installation guide to install and configure your DeviceNet hardware and the NI DNET software Use this NI DNET User Manual to learn the basics of DeviceNet and how to develop an application program The user manual also contains information on DeviceNet hardware Use the NI DNET Programmer Reference Manual for specific information about each NI DNET function and object National Instruments ix NI DNET User Manual About This Ma
62. ionship with National Instruments Patents For patents covering National Instruments products technology refer to the appropriate location Help Patents in your software the patents txt file on your media or the National Instruments Patent Notice at ni com patents Export Compliance Information Refer to the Export Compliance Information at ni com legal export compliance for the National Instruments global trade compliance policy and how to obtain relevant HTS codes ECCNs and other import export data WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS 1 NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL OF RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL COMPONENTS IN ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAUSE SIGNIFICANT INJURY TO A HUMAN 2 IN ANY APPLICATION INCLUDING THE ABOVE RELIABILITY OF OPERATION OF THE SOFTWARE PRODUCTS CAN BE IMPAIRED BY ADVERSE FACTORS INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY COMPUTER HARDWARE MALFUNCTIONS COMPUTER OPERATING SYSTEM SOFTWARE FITNESS FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED TO DEVELOP AN APPLICATION INSTALLATION ERRORS SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS MALFUNCTIONS OR FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES TRANSIENT FAILURES OF ELECTRONIC SYSTEMS HARDWARE AND OR SOFTWARE UNANTICIPATED USES OR MISUSES OR
63. matically receive a one year membership in the Standard Service Program SSP with the purchase of most software products and bundles including NI Developer Suite NI also offers flexible extended contract options that guarantee your SSP benefits are available without interruption for as long as you need them Visit ni com ssp for more information For information about other technical support options in your area Visit ni com services or contact your local office at ni com contact Training and Certification Visit ni com training for training and certification program information You can also register for instructor led hands on courses at locations around the world e System Integration f you have time constraints limited in house technical resources or other project challenges National Instruments E 1 NI DNET User Manual Appendix E Technical Support and Professional Services Alliance Partner members can help To learn more call your local NI office or visit ni com alliance You also can visit the Worldwide Offices section of ni com niglobal to access the branch office Web sites which provide up to date contact information support phone numbers email addresses and current events NI DNET User Manual E 2 ni com Glossary Symbol Prefix Value m milli 10 3 k kilo 103 A amperes AC alternating current actuator A device that uses electrical mechanical or other signals to change t
64. may be used to reproduce software or other materials belonging to others you may use NI software only to reproduce materials that you may reproduce in accordance with the terms of any applicable license or other legal restriction End User License Agreements and Third Party Legal Notices You can find end user license agreements EULAs and third party legal notices in the following locations e Notices are located in the National Instruments V Legal Information and National Instruments directories e EULAs are located in the National Instruments Shared MMDFNEULAs directory e Review National Instruments V Legal Information txt for more information on including legal information in installers built with NI products Trademarks CVI LabVIEW National Instruments NI ni com the National Instruments corporate logo and the Eagle logo are trademarks of National Instruments Corporation Refer to the Trademark Information at ni com trademarks for other National Instruments trademarks The mark LabWindows is used under a license from Microsoft Corporation Windows is a registered trademark of Microsoft Corporation in the United States and other countries Other product and company names mentioned herein are trademarks or trade names of their respective companies Members of the National Instruments Alliance Partner Program are business entities independent from National Instruments and have no agency partnership or joint venture relat
65. means that for cyclic I O connections ncOpenDnet IO is normally called with InputLength nonzero and OutputLength Zero Just as for individually polled I O you should use smaller MAC IDs for smaller cyclic I O ExpPacketRate values Doing so ensures that cyclic I O traffic is prioritized properly 4 6 ni com Chapter 4 NI DNET Programming Technigues Change of State COS 1 0 Change of State I O connections use the same timing scheme as cyclic I O connections but in addition to the ExpPacketRate COS I O sends data to the master whenever a change is detected For COS I O the cyclic transmission is used solely to verify that the I O connection still exists so the ExpPacketRate is typically set to a large value such as 10 000 10 seconds Given such a large ExpPacketRate the main performance concerns for COS I O are an appropriate MAC ID and if needed a nonzero InhibitTimer In many cases a given COS I O device cannot detect data changes very quickly If a COS device is capable of detecting quickly changing data there is a chance that it could transmit many COS messages back to back precluding other I O messages and thus dramatically impairing overall DeviceNet performance This problem is demonstrated in Figure 4 5 Back to Back Some of the COS I O Data Other I O May COS I O Changing Frequently Have Timed Out i 5 ms 10 ms 15 ms 20 ms Figure 4 5 Congestion Due to Back to Back COS 1 0
66. n Fwd and Fault Reset is BOOL boolean and the DeviceNet data type for Speed Reference is INT 16 bit signed integer Accessing 1 0 Members in LabVIEW NI DNET User Manual Many fundamental differences exist between the encoding of a DeviceNet data type and its equivalent data type in LabVIEW For example for a 32 bit integer the DeviceNet DINT data type uses Intel byte ordering lowest byte first and the equivalent LabVIEW 132 data type uses Motorola byte ordering highest byte first To make it easier for you to avoid these data type issues in your LabVIEW application NI DNET provides two functions to convert between LabVIEW data types and DeviceNet data types ncConvertForDnetWrite and ncConvertFromDnetRead These functions are used to access individual members of an I O assembly using normal Lab VIEW controls and indicators The following steps show an example of how you can use ncConvertForDnetWrite to access the Basic Speed Control Output Assembly described in the previous section 1 Use the NI DNET palette to place ncConvertForDnetWrite into your diagram 2 Right click on the DnetData in terminal and select Create Constant then initialize the first 4 bytes of the array to zero 3 Right click on the DnetType terminal and select Create Constant then select BOOL from the enumeration ni com Chapter 4 NI DNET Programming Technigues 4 Right click on the ByteOffset terminal and select Create Constant then ente
67. n an instance to affect its behavior the externally visible code of an object Within NI DNET you use NI DNET functions to execute services for objects Also known as method and operation strobed O See bit strobed I O V V volts VI Virtual Instrument VxD Virtual device driver National Instruments G 7 NI DNET User Manual Index A Analyzer 1 4 C change protocol 1 3 common questions C 3 and troubleshooting C 1 components left after NI CAN software uninstall C 4 determining NI CAN software version C 3 how many CAN interfaces can be configured C 3 interrupts required for NI CAN cards C 3 NI CAN card and power to CAN bus C 3 troubleshooting with MAX C 1 using multiple PCMCIA cards C 4 Configurator 1 4 configure DNET port 1 2 conventions used in the manual x D diagnostic tools NI resources E 1 documentation conventions x how to use manual set ix NI resources E 1 related conventions x drivers NI resources E 1 E error message interrupt resource conflict troubleshooting C 2 memory resource conflict C 2 National Instruments NI CAN hardware problem encountered C 3 NI CAN software problem encountered C 2 examples NI resources E 1 H help technical support E 1 installation and configuration NI DNET cards listed in MAX figure 1 2 verifying through MAX 1 2 change protocol 1 3 configure DNET port 1 2 instrument drivers NI resources E 1 interrup
68. n for all CAN DeviceNet hardware installed on your system To start MAX double click on the Measurement amp Automation icon on your desktop Your CAN cards are listed in the left pane Configuration under Devices and Interfaces NI CAN Devices You can test your CAN cards by choosing Tools NI CAN Test all Local NI CAN Cards from the menu or you can right click on a CAN card and choose Self Test If the Self Test fails refer to the Troubleshooting Self Test Failures section of this appendix If you have a CAN card installed but no CAN card appears in the configuration section of MAX under Devices and Interfaces you need to search for hardware changes by pressing F5 or choosing the Refresh option from the View menu in MAX If the CAN card still doesn t show up you may have a resource conflict in the Windows Device Manager Refer to the documentation for your Windows operating system for instructions on how to resolve the problem using the Device Manager C 1 NI DNET User Manual Appendix Troubleshooting and Common Questions Troubleshooting Self Test Failures Application In Use The following topics explain common error messages generated by the Self Test in MAX This error occurs if you are running an application that is using the CAN card The self test aborts to avoid adversely affecting your application Before running the self test exit all applications that use NI DNET or NI CAN If you are using LabVIEW y
69. n output of 10 V to 30 V The DeviceNet physical layer is powered from the bus using the V and V lines The power requirements for the DeviceNet port are shown in Table B 1 You should take these requirements into account when determining the requirements of the bus power supply for the system Table B 1 Power Requirements for the DeviceNet Physical Layer for Bus Powered Versions Characteristic Specification Voltage Requirement V 10 to 30 VDC Current Requirement 40 mA typical 100 mA maximum For the PCI CAN a jumper controls the source of power for the DeviceNet physical layer The location of this jumper is shown in Figure B 4 o CO 3 pii E o q o NATIONAL iV INSTRUMENTS y m ue i H H C Eb ES a is pe 5 y A Pa Fi E ACT gl rd E gas 1 Power Supply Jumper J6 3 Serial Number 2 Product Name 4 Assembly Number Figure B 4 PCI CAN Power Source Jumper National Instruments 3 NI DNET User Manual Appendix Cabling Requirements NI DNET User Manual The PCI CAN is shipped with this jumper set in the EXT position In this position the physical layer is powered from the bus the
70. ncWriteDnetExplMsg for such DeviceNet services as Reset Save Restore Get Attributes All and Set Attributes All Although the DeviceNet Specification defines the overall format of these services in most cases their meaning and service data are object specific or vendor specific Unless your device requires such services and documents them in detail you probably do not need them for your application You need the following information to use the ncWriteDnetExplMsg and ncReadDnetExp1Msg functions for a given explicit messaging service e The class and instance identifiers for the object to which the service will be directed e The service code used to identify the service e The length and format of service request and response data Some of data formats are defined by the service s overall specification such as in Appendix G DeviceNet Explicit Services in the DeviceNet Specification manual but many data formats are object specific or vendor specific For example for the Reset service Appendix G defines the service s code for use with any object but its actual data format is defined in the specification for the Identity Object e The error codes that can be returned in the service response Error codes that are common to all services can be found in Appendix H DeviceNet Error Codes in the DeviceNet Specification manual but many error codes are specific to the service object or vendor As with the ncGetDnetAttribute and ncSe
71. ng object This instance has attributes for the Output Signal on off and Diagnostic Status good fault These two attributes are often routed through a single input assembly consisting of a single byte A 12 ni com Appendix A DeviceNet Overview Figure A 7 shows an example of a Presence Sensing instance and its input assembly Presence Sensor Instance 1 Attributes Output BOOL On Delay UINT Off Delay UINT Diagnostic BOOL Mode BOOL Bt 7 6 5 4 3 2 1 0 One byte input assembly often returned as a strobe response or COS input message Figure A 7 Input Assembly for Photoeye or Limit Switch As you can see to use the data bytes contained in I O messages it is important to know the format of a device s internal input and output assemblies Device Profiles To provide interoperability for devices of the same type the DeviceNet Specification defines various device profiles The goal behind device profiles is that for a given type of device such as a photoelectric sensor it should be relatively straightforward to replace a sensor from one vendor with a sensor from another vendor devices which conform to a given profile must do the following e Exhibit the same behavior e Use the same object model certain instances are required e Contain the same input and output assemblies e Contain the same se
72. nt with the rate at which the device measures its physical input sensors For example if a temperature sensor can take a measurement at most once every 500 ms you would configure the cyclic I O connection s EPR as 500 ms Cyclic I O can be configured to send output data from master to slave but this configuration is seldom used since it is essentially the same as polled I O Cyclic I O messages can contain any amount of data The COS I O connection enables a slave device to send input data to its master when a change is detected on its physical inputs In addition to sending input data when a change is detected the COS slave also sends its input data at a slower EPR interval that lets the master know it is still functioning COS I O is typically used for devices with physical inputs that can change frequently but can have the same input value for a long time For example if a pushbutton device supports COS I O you might configure its EPR as 3 seconds since the device sends a message immediately if a button is pressed COS I O can be configured to send output data from master to slave Although master to slave COS output is seldom used it can be useful for things like front panel pushbuttons which are sent to a slave s discrete outputs such as LEDs and simple motors COS I O messages can contain any amount of data When using COS cyclic I O connections you can configure the device that receives data to send an acknowledgment so that the
73. nual Conventions bold italic monospace monospace italic The following conventions appear in this manual The symbol leads you through nested menu items and dialog box options to a final action The sequence Options Settings General directs you to pull down the Options menu select the Settings item and select General from the last dialog box This icon denotes a note which alerts you to important information Bold text denotes items that you must select or click in the software such as menu items and dialog box options Bold text also denotes parameter names Italic text denotes variables emphasis a cross reference or an introduction to a key concept Italic text also denotes text that is a placeholder for a word or value that you must supply Text in this font denotes text or characters that you should enter from the keyboard sections of code programming examples and syntax examples This font is also used for the proper names of disk drives paths directories programs subprograms subroutines device names functions operations variables filenames and extensions Italic text in this font denotes text that is a placeholder for a word or value that you must supply Related Documentation NI DNET User Manual The following documents contain information that you might find helpful as you read this manual e ANSI ISO Standard 11898 1993 Road Vehicles Interchange of Digital Information
74. ointer manipulations to convert between C language data types and DeviceNet data types National Instruments 4 11 NI DNET User Manual Chapter 4 NI DNET Programming Technigues The following steps show an example of how standard C language can be used to access the Basic Speed Control Output Assembly described in the previous section 1 Declare an array of 4 bytes as in the following NCTYPE UINT8OutputAsm 4 Initialize the array to all zero for 0 I lt 4 I OutputAsm 0 Assume you have two boolean variables RunFwd and ResetFault of type NCTYPE BOOL For LabWindows CVI these variables could be accessed from front panel buttons The following code inserts these boolean variables into OutputAsm if RunFwd OutputAsm 0 0x01 if FaultReset OutputAsm 0 0x04 Assume you have an integer variable SpeedRef of type NCTYPE_INT16 For LabWindows CVI this variable could be accessed from a front panel control The following code inserts this integer variable into OutputAsm NCTYPE INT16 amp OutputAsm 2 SpeedRef Write the output assembly to the remote device status ncWriteDnetIO objh sizeof OutputAsm OutputAsm For information on NI DNET s C language data types and their equivalent DeviceNet data types refer to Chapter 1 NI DNET Data Types of the NI DNET Programmer Reference Manual Using Explicit Messaging Services NI DNET User Manual The N
75. onding NI DNET data type you use to declare a variable for the attribute s value For example if the attribute s DeviceNet data type is INT 16 bit signed integer you should declare a C language variable of type NCTYPE INT16 then pass the address of that variable as the At tr parameter of the ncGetDnetAttribute or ncSetDnetAttribute function For LabVIEW the attribute s DeviceNet data type determines the corresponding LabVIEW data type to use with the ncConvertForDnetWrite or ncConvertFromDnetRead functions The ncConvertFromDnetRead function converts a DeviceNet attribute read using ncGetDnetAttribute into an appropriate LabVIEW data type The ncConvertForDnetWrite function converts a LabVIEW data type into an appropriate DeviceNet attribute to write using ncSetDnetAttribute For more information on these LabVIEW conversion functions refer to the Using I O Data in Your Application section National Instruments 4 13 NI DNET User Manual Chapter 4 NI DNET Programming Technigues Other Explicit Messaging Services To execute services other than Get Attribute Single and Set Attribute Single use the following sequence of function calls ncWriteDnetExplMsg ncWaitForState ncReadDnetExplMsg The ncWriteDnetExplMsg function sends an explicit message request to a remote DeviceNet device The ncWaitForState function waits for the explicit message response and the ncReadDnetExplMsg function reads that response Use
76. ontrol algorithm in LabVIEW When you install the NI DNET software the installer checks for the presence of the LabVIEW RT module If LabVIEW RT exists the NI DNET installer copies components for LabVIEW RT to your Windows system As with any other NI product for LabVIEW RT you then download the NI DNET and NI CAN software to your LabVIEW RT system using the Remote Systems branch in MAX For more information refer to the LabVIEW RT documentation After you have installed your PXI DeviceNet cards and downloaded the NI DNET software to your LabVIEW RT system you need to verify the installation Within the Tools menu in MAX select NI DNET RT Hardware Configuration The RT Hardware Configuration tool provides features similar to Devices amp Interfaces on your local system Use the RT Hardware Configuration tool to self test the DeviceNet cards and assign an interface name to each physical DeviceNet port National Instruments 1 8 NI DNET User Manual Chapter 1 NI DNET Software Overview Tools NI DNET User Manual NI DNET provides tools that you can launch from MAX Configurator The Configurator is a powerful configuration tool with Electronic Data Sheet EDS support EDS is a file on disk that contains configuration data for specific device types Each DeviceNet device has its own EDS file which is available from the device manufacturer The Configurator can search a DeviceNet network to determine information about connec
77. ontroller object an Application Object is provided for every axis motor which can be controlled using the device For more information on the classes instances attributes and services provided by DeviceNet refer to the DeviceNet Specification You can find additional information on the specific classes and instances supported by a given device in the documentation that came with the device Although the NI DNET driver software provides object instances which are used to access the DeviceNet network these objects do not correspond directly to the objects defined by the DeviceNet Specification and the NI DNET functions do not directly correspond to the services defined by DeviceNet To facilitate access to your DeviceNet network the features provided by the NI DNET driver are a simplification of the objects and services defined in the DeviceNet Specification Explicit Messaging Gonnections O National Instruments Each device on the DeviceNet network supports at least one explicit messaging connection Explicit messaging connections provide a general purpose communication path used to execute services on a particular object in a device For a given explicit messaging connection between two DeviceNet devices the device reguesting execution of the service is called the client and the device to which the service reguest is directed is called the server Your NI DNET software can be used as an explicit messaging client with any numbe
78. ore you start the communication if the Automatic mode is selected The EPR restrictions due to different values of the Po11Mode parameter still apply to the I O objects For details on these requirements refer to ncOpenDnetIO and ncOpenDnetIntf function descriptions in the NI DNET Programmer Reference Manual Step 4 Stop Communication Before you exit your application stop communication to shut down DeviceNet connections to remote devices Use the Interface Object to call the ncOperateDnetInt function with the Opcode parameter set to Stop Step 5 Close Objects Before you exit your application close all NI DNET objects using the ncCloseObject function Multiple Applications on the Same Interface NI DNET User Manual The NI DNET software allows multiple NI DNET applications to use the same interface object simultaneously as long as the interface configuration remains the same For example you can run both the SingleDevice example and Configurator on DNETO as long as the Interface MacId BaudRate and PollMode parameters are the same in both applications Configurator uses a Po11Mode of Automatic Similarly you can open up two copies of the SingleDevice example and communicate with two different devices as if it were through a single application These same rules apply to the I O Object and the Explicit Messaging Object As long as all the configuration attributes are the same any object can be opened multiple times You c
79. ou may need to exit LabVIEW to unload the NI DNET driver Memory Resource Conflict This error occurs if the memory resource assigned to a CAN card conflicts with the memory resources being used by other devices in the system Resource conflicts typically occur when your system contains legacy boards that use resources not properly reserved with the Device Manager If a resource conflict exists write down the memory resource that caused the conflict and refer to the documentation for your Windows operating system for instructions on how to use the Device Manager to reserve memory resources for legacy boards After the conflict has been resolved run the Self Test again Interrupt Resource Conflict This error occurs if the interrupt resource assigned to a CAN card conflicts with the interrupt resources being used by other devices in the system Resource conflicts typically occur when your system contains legacy boards that use resources not properly reserved with the Device Manager If a resource conflict exists write down the interrupt resource that caused the conflict and refer to the documentation for your Windows operating system for instructions on how to use the Device Manager to reserve interrupt resources for legacy boards After the conflict has been resolved run the Self Test again NI CAN Software Problem Encountered NI DNET User Manual This error occurs if the Self Test detects that it is unable to communicate correctly with
80. r 0 as the byte offset 5 Right click on the 8 TF in terminal and select Create Control In the front panel control that appears you can use the button at index 0 to control Run Fwd and the button at index 2 to control Fault Reset 6 Using the NI DNET palette place ncConvertForDnetWrite into your diagram 7 WiretheDnetData out terminal from the previous Convert into the DnetData in terminal of this Convert 8 Right click on the DnetType terminal and select Create Constant then select INT from the enumeration 9 Right click on the ByteOffset terminal and select Create Constant then enter 2 as the byte offset 10 Right click on the 132 116 18 in terminal and select Create Control You can use the front panel control that appears to change Speed Reference 11 Using the NI DNET palette place ncWriteDnetIO into your diagram 12 Wirethe DnetData out terminal from the previous Convert into the Data terminal of ncWriteDnet10 For more information on the ncConvertForDnetWrite and ncConvertFromDnetRead functions refer to the NI DNET Programmer Reference Manual For information on LabVIEW data types and their equivalent DeviceNet data types refer to Chapter 1 NI DNET Data Types in the NI DNET Programmer Reference Manual Accessing 1 0 Members in C Since DeviceNet data types are very similar to C language data types individual I O members can be accessed in a straightforward manner You can use the standard C language p
81. r and format of these data bytes is defined by the specification for the service Table A 3 Explicit Message Response Field Description Service Code This number indicates success or failure for execution of the service If this number is the same as the Service Code of the request the service executed successfully If this number is 14 hex the service failed to execute due to an error Service Data If the service executed successfully this field contains data bytes which are specific to the Service Code The number and format of these data bytes are defined by the specification for the service If the service failed to execute the first byte of Service Data contains a General Error Code which describes the error and the second byte contains an Additional Error Code which qualifies the error The DeviceNet Specification defines valid values for the General Error Code and Additional Error Code The DeviceNet Specification defines a set of services supported in a common way by different devices These common services include Reset Save Restore Get Attribute Single and Set Attribute Single NI DNET User Manual A 6 ni com Appendix A DeviceNet Overview The Get Attribute Single service obtains the value of a specific attribute within a device s object and the Set Attribute Single service sets the value of an attribute These Get and Set services are the most commonly used explicit messaging servic
82. r of DeviceNet server devices Using an explicit messaging connection the client device sends an explicit message reguest to the server device This reguest indicates the service to perform and the object to which the service is directed When the server 5 NI DNET User Manual Appendix A DeviceNet Overview receives the explicit message reguest it executes the service and sends an explicit message response to the client device If the service executed successfully this response contains information reguested by the client The MAC ID address of the explicit message client and server is contained in the header of the DeviceNet explicit messages The following tables describe the general format of DeviceNet explicit message requests and responses as they appear on the DeviceNet network Table A 2 Explicit Message Request Field Description Service Code This number identifies the service requested by the client The DeviceNet Specification defines valid service codes Class ID This number identifies the class to which the service is directed The DeviceNet Specification defines valid class IDs Instance ID This number identifies the instance to which the service is directed If the instance ID is zero the service is directed to the entire class If the instance ID is one or greater the service is directed to a specific instance within the class Service Data Data bytes specific to the Service Code The numbe
83. re media that do not execute programming instructions if National Instruments receives notice of such defects during the warranty period National Instruments does not warrant that the operation of the software shall be uninterrupted or error free A Return Material Authorization RMA number must be obtained from the factory and clearly marked on the outside of the package before any equipment will be accepted for warranty work National Instruments will pay the shipping costs of returning to the owner parts which are covered by warranty National Instruments believes that the information in this document is accurate The document has been carefully reviewed for technical accuracy In the event that technical or typographical errors exist National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition The reader should consult National Instruments if errors are suspected In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it EXCEPT AS SPECIFIED HEREIN NATIONAL INSTRUMENTS MAKES NO WARRANTIES EXPRESS OR IMPLIED AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE CUSTOMER S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER NATIONAL INSTRUM
84. read input data received from the DeviceNet network Loop back to step 1 as needed Complete the following steps with an Explicit Messaging Object 1 National Instruments Call the ncwaitForState function with the DesiredState parameter setto Established This ensures that the explicit message connection is established before you send the first explicit message request To get an attribute from a remote DeviceNet device call the ncGetDnetAttribute function To set the value of an attribute in a remote DeviceNet device call the ncSetDnetAttribute function To invoke other explicit message services in a remote DeviceNet device use the ncWriteDnetExplMsg function to write the service request the ncWaitForState function to wait for the service response and the ncReadDnetExp1Msg function to read the service response Loop back to step 2 as needed 3 9 NI DNET User Manual Chapter 3 Developing Your Application Addition of Slave Connections after Communication Start If you need to add I O and Explicit Messaging connections after the communication on the network has started you can call ncOpenDnetExp1Msg and ncOpenDnetIO as long as the Interface Object s poll mode had been configured to NC POLL SCAN Scanned or NC POLL INDIV Individual Since the Automatic poll mode NC POLL AUTO calculates the expected packet rate EPR based on the estimated network bandwidth all the I O connections have to be opened bef
85. ress NidnetLib LPCSTR ncReadDnetIO If Get ProcAddress fails it returns a NULL pointer The following code fragment illustrates how to verify that none of the calls to GetProcAddress failed if PncOpenDnetIO NULL PncCloseObject NULL PncReadDnetIO NULL FreeLibrary NidnetLib printf GetProcAddress failed 3 5 NI DNET User Manual Chapter 3 Developing Your Application 3 Configure your application to de reference the pointer to call an NI DNET function as illustrated by the following code NCTYPI NCTYPI status if s p p STATUS status _ OBJH MyObjh atus 0 PncOpenDnetIO DNETO amp MyObjh printf ncOpenDnetIO failed j 4 Freenican dll Before exiting your application you need to free nican d11 with the following command FreeLibrary NidnetLib Programming Model for NI DNET Applications NI DNET User Manual The following steps provide an overview of how to use the NI DNET functions in your application The steps are shown in Figure 3 1 in flowchart form The NI DNET functions are described in detail in the NI DNET Programmer Reference Manual ni com Chapter 3 Developing Your Application Start 1 Open Interface object 2 Open all I O and Explicit Messaging EM objects required for your application 3 Call ncSetDriverAttr if needed Start communication Your DeviceNet Appl
86. ritten in LabVIEW status checking is handled automatically For all NI DNET functions the lower left and right terminals provide status information using LabVIEW Error Clusters LabVIEW Error Clusters are designed so that status information flows from one function to the next and function execution stops when an error occurs For more information refer to the Error Handling section in the LabVIEW online reference Within your LabVIEW block diagram you wire the Error in and Error out terminals of NI DNET functions together in succession When an error is detected in an NI DNET function status field true all NI DNET functions wired together are skipped except for ncCloseObject The ncCloseobject function executes regardless of whether an error occurred thus ensuring that all NI DNET objects are closed properly when execution stops due to an error Depending on how you want to handle errors you can wire the Error in and Error out terminals together per object group a single open close pair per device group together Explicit Messaging and I O Objects for a given device or per network group all functions for a given interface 3 11 NI DNET User Manual Chapter 3 Developing Your Application As with any other LabVIEW error cluster you can view error descriptions using built in LabVIEW features such as Explain Error in the Help menu or the Simple Error Handler VI in your diagram Checking Status in C C and Visual Basic
87. rs should be placed in a system with more than two devices DeviceNet Device DeviceNet DeviceNet DeviceNet Device Device Device _ National Instruments Figure B 7 Termination Resistor Placement The termination resistors on a cable should match the nominal impedance of the cable DeviceNet requires a cable with a nominal impedance of 120 therefore a 120 resistor should be used at each end of the cable Each termination resistor should each be capable of dissipating at least 0 25 W of power B 7 NI DNET User Manual Appendix Cabling Requirements Cabling Example Figure B 8 shows an example of a cable to connect two DeviceNet devices 5 Pin Combicon Pin 4 Pin 2 Pin 3 Pin 5 Pin 1 9 Pin 9 Pin 5 Pin D Sub D Sub Combicon CAN H Pin 7 Pin 7 Pin 4 1200 120 0 CAN L Pin 2 Pin 2 Pin 2 Shield 5 Pin 5 Pin 3 Pin 9 MR Pin 9 Pin 5 Pin3 Hs Pin 3 Pin 1 Power Connector va 5 Y NI DNET User Manual Figure B 8 B 8 Cabling Example ni com Troubleshooting and Common Questions This appendix describes how to troubleshoot problems with the NI DNET software and answers some common questions Troubleshooting with the Measurement amp Automation Explorer MAX Missing CAN Card National Instruments MAX contains configuration informatio
88. t of configurable attributes In addition to required features most device profiles define a variety of optional features When an optional feature is supported by a vendor it must be supported as defined by the DeviceNet Specification Device profiles also allow for vendor specific features National Instruments A 13 NI DNET User Manual Appendix A DeviceNet Overview The DeviceNet Specification provides device profiles for such devices as photoelectric sensors limit switches motor starters position controllers and mass flow controllers Open DeviceNet Vendors Association ODVA This chapter provides only a short summary of DeviceNet For additional information such as a list of DeviceNet products and how to purchase the DeviceNet Specification refer to the ODVA Web site at www odva org NI DNET User Manual A 14 ni com Gabling Reguirements This appendix describes the cabling reguirements for the hardware Cables should be constructed to meet these reguirements as well as the reguirements of DeviceNet DeviceNet cabling reguirements can be found in the DeviceNet Specification Connector Pinouts O National Instruments The PCI CAN PXI 8461 and the PCMCIA CAN bus powered cable each have a Combicon style pluggable screw terminal connector The PCMCIA CAN bus powered cable also has a DB 9 D SUB connector The 5 pin Combicon style pluggable screw terminal follows the pinout required by the DeviceNet Speci
89. t resource conflict troubleshooting C 2 K KnowledgeBase E 1 L LabVIEW Real Time RT software configuration 1 3 tools 1 4 MAX NI DNET cards listed in MAX figure 1 2 tools launched from 1 4 Measurement amp Automation Explorer MAX See MAX NI DNET User Manual Index memory resource conflict troubleshooting C 2 missing CAN card troubleshooting C 1 National Instruments support and services E 1 NI I O Trace 1 5 NI CAN hardware problem encountered troubleshooting C 3 NI CAN software problem encountered troubleshooting C 2 NI DNET verify hardware installation in MAX figure 1 2 P PCI CAN series board specifications D 1 PCMCIA CAN series card specifications D 1 port characteristics D 3 programming examples NI resources E 1 PXI 8461 parts locator diagram figure B 5 port characteristics D 3 R related documentation x S self test failures troubleshooting C 2 software LabVIEW Real Time RT tools 1 4 LabVIEW Real Time RT configuration 1 3 NI resources E 1 NI DNET User Manual 1 2 specifications PCI CAN series board D 1 PCMCIA CAN series card D 1 support technical E 1 T technical support E 1 training and certification NI resources E 1 troubleshooting and common guestions C 1 interrupt resource conflict C 2 memory resource conflict C 2 missing CAN card C 1 NI CAN software problem encountered C 2 C 3 self test failures C
90. tDnetAttribute functions the service data formats for the request and response are specified in terms of DeviceNet data types These DeviceNet data types are converted to from the data types of your programming environment C or LabVIEW as discussed in previous sections NI DNET User Manual 4 14 ni com Chapter 4 NI DNET Programming Technigues Handling Multiple Devices This section describes technigues you can use to efficiently implement an application that communicates with a large number of DeviceNet devices In such an application there might be only one call to ncOpenDnetIntf only one network but there are usually multiple calls to ncOpenDnet 10 and possibly ncopenDnetExplMsg Configuration If the configuration parameters used with ncOpenDnet IO tend to change over time you might want to organize them in data structures instead of using constants For the C programming language you can declare a structure typedef to store the parameters of ncOpenDnet IO similar to the following typedef struct NCTYPE UINT32DeviceMacId NCTYPE CONN TYPEConnectionType NCTYPE UINT32InputLength NCTYPE_UINT320utputLength NCTYPE_UINT32ExpPacketRate OpenDnetIO_Struct For LabVIEW a cluster that contains these parameters is already defined for use with ncOpenDnetI0 You can use this structure cluster to declare an array that contains one entry for each call you make to ncOpenDnet 10 In LabVIEW and
91. ted devices load the related EDS files automatically read and write the device parameters and change a device MAC ID The Configurator helps you with the NI DNET development by providing e device list and each device s MAC ID which are useful for the NI DNET ncOpenDnetIntf ncOpenDnetExplMsg and ncOpenDnet10 functions e Each device s parameter list You must import the device EDS file to get the parameter list You can also get each parameter s ClassID InstanceID AttributeID and type information which are useful for the NI DNET ncGetDnetAttribute ncSetDnetAttribute ncConvertFromDnetRead and ncConvertForDnetWrite functions e Bach device s supported I O connection and related help information You must import the device EDS file to get the help information which is useful for the NI DNET ncOpenDnet IO ncConvertFromDnetRead and ncConvertForDnetWrite functions To launch the Configurator right click the DeviceNet interface such as DNETO in MAX and select Configurator Analyzer The Analyzer monitors the DeviceNet network and interprets the captured CAN messages according to the DeviceNet protocol It displays the messages together with their parameters You can display certain types of messages using powerful filters and find options You also can get the message statistics in the Analyzer The Analyzer is useful for troubleshooting and analysis of DeviceNet networks and systems To launch the Analyzer rig
92. ter 3 Developing Your Application For C applications files with c extension include the header file by adding a tinclude to the beginning of your code like this tinclude nidnet h For C applications files with cpp extension define cplusplus before including the header such as define _cplusplus include nidnet h The cplusplus define enables the transition from C to the C language NI DNET functions The reference for each NI DNET function is provided in NJ DNET Programmer Reference Manual which you can open from Start All Programs National Instruments NI DNET You can find examples for Visual C in the examples subfolder of the Borland C folder Each example is in a separate folder A c file with the same name as the example contains a description the example in comments at the top of the code Other Programming Languages NI DNET User Manual You can directly access NI DNET from any programming environment that allows you to request addresses of functions that a dynamic link library DLL exports The functions used to access a DLL in this manner are provided by the Microsoft Win32 functions of Windows Using these Microsoft Win32 functions to access a DLL is often referred to as direct entry To use direct entry with NI DNET complete the following steps 1 Load NI DNET DLL nican d11 The following C language code fragment illustrates how to call the Win32 LoadLibrary function and check
93. tes of all polled I O devices do not fit into two clear groups background polling can still be inefficient For example assume you have four different polled I O sensors capable of updating measured input at 10 ms 35 ms 100 ms and 700 ms respectively Each device responds to its poll command within 1 ms but measures data at a different rate such as a pushbutton for 10 ms and a temperature sensor for 700 ms You could group these into a foreground rate of 10 ms and a background rate of 700 ms but then much DeviceNet bandwidth would be wasted polling the 35 ms and 100 ms devices at the foreground rate For this situation the individual polling scheme is most appropriate To configure individual polling first set the Po11Mode parameter of ncOpenDnetIntf to Individual Then for each polled I O connection you configure ncOpenDnetIO with ConnectionType set to Poll you must set ExpPacketRate to the rate desired for that device Unlike the scanned polling or background polling scheme each poll command is no longer associated with the strobe command s rate but instead is solely based on its ExpPacketRate 4 5 NI DNET User Manual Chapter 4 NI DNET Programming Technigues Since the poll commands are not synchronized for individual polling they can often be scattered relatively randomly They can be evenly interspersed for a while then suddenly occur in bursts of back to back messages Because of this inconsistency you should use smaller
94. the PXI Specification and CompactPCI Specification It features the National Instruments MITE bus interface chip that connects the card to the PXI or CompactPCI I O bus With a PXI 8461 card you can make your PXI or CompactPCI chassis communicate with and control DeviceNet devices PCMCIA CAN hardware is a 16 bit Type II PC Card that is software configurable and compliant with the PCMCIA standards for 16 bit PC cards With a PCMCIA CAN card you can make your PC compatible notebook with PCMCIA slots communicate with and control DeviceNet devices The PCI CAN PXI 8461 or PCMCIA CAN in your DeviceNet kit is fully compliant with the DeviceNet Specification of the DeviceNet hardware uses the Intel 386EX embedded processor to implement time critical features provided by the NI DNET software The cards communicate with the NI DNET driver through on board shared memory and an interrupt The DeviceNet physical communication link protocol is based on the Controller Area Network CAN protocol The physical layers of the PCI CAN PXI 8461 and PCMCIA CAN fully conform to the DeviceNet physical layer requirements The physical layer is optically isolated to 500 V and is powered from the DeviceNet bus power supply DeviceNet interfacing is accomplished using the Intel 82527 CAN controller chip 2 1 NI DNET User Manual Chapter 2 NI DNET Hardware Overview For more information on the DeviceNet physical layer and cables used to connect to your
95. to a remote DeviceNet device physical device attached to your interface by a DeviceNet cable Since only one explicit messaging connection is created for a given device the Explicit Messaging Object is also used for features that apply to the device as a whole Use the Explicit Messaging Object to do the following e Execute the DeviceNet Get Attribute Single service on the remote device ncGetDnetAttribute e Execute the DeviceNet Set Attribute Single service on the remote device ncSetDnetAttribute e Send any other explicit message request to the remote device and receive the associated explicit message response ncWriteDnetExp1Msg ncReadDnetExplMsg e Configure NI DNET settings that apply to the entire remote device The I O Object represents an I O connection to a remote DeviceNet device physical device attached to your interface by a DeviceNet cable The I O Object usually represents I O communication as a master with a remote slave device but it can also be used for I O communication as a slave The I O Object supports as many master slave I O connections as currently allowed by the DeviceNet Specification This means that you can use polled strobed and COS cyclic I O connections simultaneously for a given device As specified by the DeviceNet Specification only one master slave I O connection of a given type can be used for each device MAC ID For example you cannot open two polled I O connections for the same device
96. transmitting device can verify that the data was received successfully For example if you configure slave to master COS I O input length nonzero the master sends an acknowledgment to the slave each time it receives an input message Since the acknowledgment message is used for verification only it does not contain data If this verification can be handled using other means such as using strobed I O to verify device status the acknowledgment message can be suppressed For information on how to suppress COS cyclic acknowledgments using NI DNET refer to the description of the I O Object in the NI DNET Programmer Reference Manual A 10 ni com Appendix A DeviceNet Overview Since COS and cyclic I O use the same messages on the DeviceNet network they cannot be used simultaneously for a given slave device Also polled I O uses the same messages on the DeviceNet network as master to slave output messages of COS cyclic I O This means that a slave device can use slave to master COS cyclic I O simultaneously with polled I O but not master to slave COS cyclic I O Figure A 5 shows an example of four COS cyclic I O connections 6 Byte COS to Slave 12 Byte Cyclic EPR 400 ms to Slave no ACK 100 ms Output data Input data Master MAC ID 1 4 Byte COS to Master EPR 200 ms i Cyclic to Master 2 Byte Cyclic to Master EPR 500 ms no
97. umidity O National Instruments D 1 10 67 x 17 46 cm 4 2 x 6 9 in 5 VDC 775 mA typical 5 pin Combicon style pluggable DeviceNet screw terminal high speed CAN only 0 to 55 C 10 to 90 noncondensing 20 to 70 C 5 to 90 noncondensing 8 56 x 5 40 x 0 5 cm 3 4 x 2 1 x 0 4 in 500 mA typical Cable with 9 pin D SUB and pluggable screw terminal for each port 0 to 55 C 10 to 90 noncondensing NI DNET User Manual Appendix D Hardware Specifications Storage environment Ambient temperature Relative humidity PXI CAN Series Dimensi ns sinusining Power Operating environment Ambient temperature Relative humidity Storage environment Ambient temperature Relative humidity Functional Shock Random Vibration Operating tete ote Nonoperating NI DNET User Manual D 2 20 to 70 C 5 to 9096 noncondensing 16 0 x 10 0 cm 6 3 x 3 9 in 5 VDC 775 mA typical 9 pin D SUB for each port standard 5 pin Combicon style pluggable DeviceNet screw terminal high speed CAN only 0 to 55 C 10 to 90 noncondensing
98. vely slowly such as temperature Background polling provides many of the same advantages as scanned polling The handling of only two groups optimizes performance Also 4 4 ni com Chapter 4 NI DNET Programming Technigues background polling maintains overall network consistency because NI DNET evenly disperses all background poll commands among multiple foreground cycles In other words all background poll commands are not sent in guick succession and thus do not generate guick bursts of traffic on the network Figure 4 3 shows a background polling example which resolves the problem discussed previously Devices at MAC ID 17 and 30 are foreground polled every 20 ms as before Devices at MAC ID 14 and 20 are background polled every 60 ms 3 times the 20 ms foreground rate The shaded areas indicate other message traffic 8 eo SE e oe A o o v o0 o 0 o o o E 5 NOE amp amp KO cC co o 6 TOO y o 00 O O m mr Y 28 222 88 po o ER o o0 EE o 000 EES co DI oo o o o Oo o oot t o aa m a a m aa aa m ll ms 20 ms 40 ms 60 ms National Instruments Figure 4 3 Background Polling Timing Example Individual Polling When the underlying response ra
99. view Installation and Configuration essent rennen 1 1 Measurement amp Automation Explorer MAX seen 1 1 Verify Installation of Your DeviceNet Hardware eese 1 2 Configure DeviceNet 1 2 Change Protocol isinai detecte egit pedes 1 3 LabVIEW Real Time RT Configuration eese 1 3 HEU MP 1 4 Configurator art P e tete reete deii en 1 4 Analyzer ior dat tb RE PH RPM ar 1 4 NIVO Trace ois PS 1 5 NI DNET Objects at deae ot P eet t tes 1 5 Interface ODbJect 2 EE Ra d eR AE 1 6 Explicit Messaging Object itecto 1 6 VO Object utente eO Un AS HIRED Hg eer Pet 1 6 Example ten n err HE RIDERE RE PIT Gr A UTERE STRIS 1 7 Using NECAN with NEDNBT iine Saeed ahead eches teint ches due e duos 1 7 Chapter 2 NI DNET Hardware Overview Types of Hardware avin EYES eS er I iita 2 1 Differences Between CAN Kits and DeviceNet Kits eee 2 2 Chapter 3 Developing Your Application Accessing NI DNET from your Programming Environment eese 3 1 LabVIEW tact eet e Ama aa TA 3 1 LabWindows CVI osc sce e RE reet ea aga koh vea ein PEE ed kad ena 3 2 Microsoft Visual te EE OE EUH avatuna 3 2 Microsoft ere e ER E E nre Ene eo ERE Re Eee ER NES ER ae 3 3 National Instruments V NI DNET User Manual Contents Borland C C E
100. y P PC peer to peer PLC polled I O protocol RAM remote resource scanned polling Sensor Server NI DNET User Manual personal computer DeviceNet communication scheme in which each device communicates as a peer and connections are established among devices as needed Programmable Logic Controller Master slave I O connection in which the master sends a poll command to a slave then receives a poll response from that slave A formal set of conventions or rules for the exchange of information among devices of a given network Random access memory Within NI DNET anything that exists in another device of the device network not on the same host as the NI DNET driver Hardware settings used by National Instruments DeviceNet hardware including an interrupt request level IRQ and an 8 KB physical memory range such as D0000 to D1FFF hex seconds A polled I O communication scheme in which all poll commands are sent out at the same rate in quick succession A device that measures electrical mechanical or other signals from an external real world variable in the context of device networks sensors are devices that send their primary data value onto the network examples include temperature sensors and presence sensors Also known as transmitter In explicit messaging connections the server is the device to which the service is directed G 6 ni com Glossary service An action performed o

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