PAM-ISA Opc Server
Contents
1. D COM Distributed Common Obiect Model OLE Obiect Linking and Embedding OPC OLE for Process Control PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 OPC Overview OPC which stands for OLE for Process Control was introduced by a group of industrial companies to define a common way for exchanging data between devices PLCs and Windows applications OPC is only a specification that defines the interfaces used to access the device data The first version of the OPC specification was released in august 1996 It consists of three parts DataAccess Alarm amp Event Handling and Historical DataAccess The DataAccess specification has undergone several revisions The latest release Version 2 0 has been available since late 1998 Alarm amp Event Handling as well as the Historical DataAccess is not yet implemented 1 for the PAM ISA device and will not be discussed in this document OPC is based on the COM DCOM architecture widely used on Microsoft platforms as a communication standard This allows PC applications to access device information from different platforms and even remotely over network connections Since OPC is a common standard it greatly simplifies the writing of client applications f hardware manufacturers support the OPC interface to their devices it is not necessary to write separate device drivers The OPC interface can be accessed from any programming language like C and even script languages like Visual2. 53 94 186 73 228 94 64 Nov convert the byte array back to a Real realRes VBConv RealFromByteArray arrayRes realRes 123 567 PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Appendix A Status and Error Codes Driver Status Status Code Description OxFFFFFFFF Error State 0x01 Uninitialized state running device driver internal initialization 0x02 Waiting for synchronization from PAM 0x04 Initialization state Download new application Pam gets some information from the driver 0x08 Watchdog is running and Messages are flowing through the dual port 0x10 Device driver is waiting for a reset command from the PAM 0x20 Special state indicating an access to the Jtag interface of the PAM PAM s FPGA and FLASH programmation Table 9 Driver Status Codes Driver Error Error Code Description 0 OK 0x0D03001 Unknown error 0x0D03002 Not enough memory 0x0D03003 No device found on specified IO port 0x0D03004 Problem mapping the dual port memory 0x0D03005 Problem initializing the dual port memory 0x0D03006 Internal error Unable to initialize the JTAG manager 0x0D03007 Internal error Unable to initialize the command interpreter 0x0D03008 Internal error Unable to initialize the state manager 0x0D03009 Internal error Problem starting the message thread 0x0D0300A Internal
3. application Description The PAM ISA Opc Server is a COM component that appears in the Windows registry with the name ACC PAMISA_OpcServer 20 Version 1 0 xx of the PAM ISA Opc Server supports only the DataAccess interface defined by the OPC specification The PAM ISA Opc Server can be connected to only one PAM device During startup the PAM ISA Opc Server is initialized and creates an OPC item object for each variable available on the connected PAM A variable of the PAM ISA device is identified by its name which is stored in the item object There are two kinds of variables SystemInfo and UserVariables The Systeminfo variables are common to all PAM s UserVariables are the variables used in PAM applications and declared as Channel Variables PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 PAM ISA OPC SERVER DESCRIPTION The PAM ISA Opc Server provides the follovving items Name Description User variables Commld evar ID gt See Table 5 SEQARABE One item for each Channel variable lt var ID gt is a hex number to identify the user variable This id is defined with the COMM ID attribute of the CHANNEL_REFERENCE declaration for programming details see 5 Channel variables declared as OUTPUT are read only channel variables declared as INPUT are write only Systeminfo variables System Reset PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Used to
4. be removed with the method DropCallbackReference The interface IOPCAsynclODisp can be optioned from the group interface Dim gConnection As Long Dim aio As IOPCAsyncIODisp Set aio gOpcGroup gConnection aio AddCallbackReference 1 Sheet1 aio DropCallbackReference gConnection gConnection 0 Type conversion with Visual Basic The values provided by the PAM ISA Opc Server are limited to the data types Real Integer and Boolean But in some cases e g the pam status the value needs to be interpreted byte wise Whereas this conversion can easy be done with Integers and Booleans Visual Basic does not provide an interface to do this with Real values Therefore within the setup of the PAM ISA Opc Server an ActiveX Control is included which allows the conversion of Real values to Byte arrays and vice versa PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Page 23 PAM ISA OPc DEMO Page 24 EXCEL SHEET APPLICATION To access this ActiveX Control select the AccVBConv 1 0 Type Library in the Visual Basic reference list The following example illustrates how this interface has to be used Dim vBConv As AccVBConv Dim dval As Double Dim arrayRes As Variant Dim realRes As Variant Create the AccVBConv interface first Set vBConv CreateObject ACCVBConv AccVBConv dval 123 567 Convert dval to an 8 byte array arrayRes VBConv ByteArrayFromReal dval arreyRes 63
5. variable SAM parameters CRC Read only variable Table 1 SEQARABE PAM ISA Opc Server Items PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 PAM ISA Opc Demo 4 Introduction Atlas Copco Controls has prepared a demonstration that illustrates how the PAM ISA Opc Server is used in practice This demonstration utilizes the PAM ISA Opc Server Version 1 0 xx together with an OPC client sample application realized using Excel This section describes how the demo application must be installed in order to run the demonstration The key parts of the Excel application are discussed in more detail and use of the OPC automation interface with Visual Basic is explained System Requirements The following system configuration is necessary to install and run the demo application Hardware Pentium 48 Mbyte RAM PAM ISA p n 9032 011 899 PAM to PC Communications Cable p n 9032 011 929 OS Microsoft Windows NT Windows 98 or 2000 Software Microsoft Office 97 Atlas Copco Controls ProMotion V201 1 There s no need to connect any SAM Drives to the PAM ISA device in order to run 1 the demo application But the optical ring must be closed by a single fibber PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Page 15 PAM ISA OPc DEMO Page 16 NSTALLATION Installation Hardware Configuration Before installing the PAM ISA card in your PC you must insure that the port address assigned to the P
6. AM ISA does not conflict with the port address of any other device on the ISA bus If necessary the PAM ISA port address can be reconfigured as shown in Table 3 SEQARABE After installing the PAM ISA connect the PAM to PC Communications Cable between the PAM ISA service connector see Figure 4 and designated PC COM connector Port Address Address Jumpers 300 H 307 H 1 3 308 H 30F H 1 3 4 310 H 317 H 1 2 318 H 31F H 1 2 3 4 notes factory default short circuit Table 3 SEQARABE PAM ISA Port Address Configuration Settings Fault Indicator red Run Indicator green A Address jumpers Top vievv FATAL Z 4 output connector EasyBus IN EasyBus OUT Pah018 a cdr Figure 4 PAM ISA Connectors Indicators and Address Jumpers PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 PAM ISA OPc DEMO NSTALLATION Be sure the povver is svvitched off before installing or removing the PAM ISA card from your PCI After installing the PAM ISA card insert the ProMotion Collection 1999 04 CD ROM or nevvest collection in your CD ROM Drive ProMotion V201 or higher contains all software necessary to install and run the demo as well as PAM Tools software required to download the demo application program to the PAM Promotion Installation
7. Basic or Java Script The OPC interface also allows multiple users access to the same device simultaneously Structure The implementation of the OPC interface specification is called the OPC Server Applications that use OPC servers are called OPC Clients An OPC Client can access multiple OPC Servers at the same time OPC Server VendorA OPC OoPCllient1 OPCClient 2 erver VendorB OPC Server Vendor OPcClients43 Figure 1 OPC Client Server Relationship PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Page 7 OPC NTERFACE An OPC Server represents an image of a physical device This is transparent for the OPC Clients and they vvork vvith the OPC Server as if they vvere communicating with the device directly The OPC DataAccess is composed of three categories of objects the server itself the group and the item An item represents a physical I O or variable and is associated with attributes like Name Value Quality and TimeStamp Items are created by the OPC server and can be accessed and changed by the OPC clients using read and write operations The OPC server maintains a cache of all the items of a device which is kept up to date automatically The client usually accesses the cached item data in order to optimize the communication load Groups are used to organize the items that an OPC Client wants to access Items are generally assigned to groups based on the update rate needed Ite
8. From master setup select Official versions and install ProMotion V201 Then install the service pack 201 1 or higher Demo Installation and Setup The PAM ISA Opc Demo can be installed on your hard disk using the master setup program included with the ProMotion CD To run the setup program insert the CD into your CD drive and from the Evaluation versions menu page select PAM ISA Opc Server Setup will guide you through the installation and all files and registry entries necessary to run the demo will be automatically installed on you PC Setup will install the following components on your machine PAM ISA Opc Server PAM ISA Opc Demo Excel Sheet e Demo PAM application must be downloaded to PAM_ISA using PAM Tools PAM ISA windows driver After installation you will find in the ACC ProMotion folder of the Windows Start menu the folder PAM ISA Opc Server containing the following entries Demo Link to the Excel Sheet Demo application to start the demo Uninstall PAM ISA Opc Server Remove complete installation of PAM ISA Opc Demo User Manual User Manual in PDF format PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Page 17 PAM ISA OPc DEMO EXCEL SHEET APPLICATION PAM ISA software configuration Using PAM Tools first check if you need to upgrade PAM bootware and firmware Check if tools displayed version is corresponding to the indicated version into installed promotion readme The delivered demo applicat
9. This version replaces all previous versions of this document Atlas Copco Controls has made every effort to insure this document is complete and accurate at the time of printing In accordance with our policy of continuing product improvement all data in this document is subject to change or correction without prior notice Atlas Copco Controls SA Zone industrielle La Rippe CH 1303 Penthaz Switzerland PAM ISA Opc Server User Manual Ordering Number 006 8036 Rev May 22 2000 Ordering No 006 8036 Rev May 22 2000 O 2000 by Atlas Copco Controls SA All rights reserved PAM ISA Opc Server User Manual Page 2 DOC 006 8036 Rev May 22 2000 Table of Contents TOC Table of Content ez a AA oriented eae 3 ntroductiomausua ada aa asan 5 P rposeza en n s b bin tegen i 5 SPENT 5 References te xx AAA 5 Documents m bars bade AA AA dae eased ee ee 5 EE A eee eee 6 A 7 leU lt T tii aed nih ed ER A URA A y IA R H d 7 olructuree m y n olumlu mi An 7 tac LU De 8 PAM ISA OPC 11 O 11 System architecture ici 11 DESCNPtON un eee aba a aba ayi hl 12 PAM ISA Ope Demo coo Aaaa 15 Introduccion e tes io 15 System Requirements cc eccecessecceceeceececeeseceneeesseceeeeeseeceeeeserenedenseceeeenerenerseees 15 Installation n ai aa 16 Hardware ee esec e eree e ereenn 16 Promotion Installation nn
10. ate events Internal error Unable to communicate with the Pam ISA device driver 0x0D03106 Unable to get information about application variables 0x0D03107 Internal error Unable to initialize application variables 0x0D03108 Internal error Unable to initialize Pam iSA common variables 0x0D03109 Number of SAM declared by the application does not correspond with the actual hardware 0x0D0310A Internal error Unable to start internal thread 0x0D0310B Unable to write variable No active session 0x0D0310C Internal error Uninitialized session manager has received a start cmd 0x0D0310D Internal error Unable to initialize ORB 0x0D0310E Internal error Unable to initialize ORB DPLink Table 10 Driver Error Codes System State Status Code Description 0x01 Booting State stopped 0x02 Running State 0x03 Fatal Error State 0x04 Busy state transition Table 11 Pam Status Codes PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000
11. ateMgtDisp lIOPCSynclODisp IOPCAsynclODisp Item IOPCItemDisp Interfaces written in brackets are defined to be optional i e they don t have to be implemented to meet the OPC standard Hovvever the PAM ISA Opc Server supports all interfaces excepted the ones written in italic style There are two kinds of interfaces custom interfaces and the automation interfaces Whereas the custom interfaces are used with programming languages like Visual C and Java the automation or dispatch interfaces with ending Disp are designed for script languages like Visual Basic or Java Script These two kinds of interfaces usually provide the same functionally and differ only in the way to use them PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Page 9 OPC NTERFACE PAM ISA Opc Server User Manual Page 10 DOC 006 8036 Rev May 22 2000 PAM ISA OPC Server Introduction In this section the PAM ISA Opc Server provided by Atlas Copco Controls is described in more detail Information concerning the PAM ISA device can be found in the document 3 System architecture The PAM ISA Opc Server provides a common interface to the PAM device for OPC clients using the COM technology OPC clients interact only with PAM ISA Opc Server objects and never communicate directly with the PAM device The fact that the OPC Server uses a Windows driver to communicate with the PAM device is completely hidden from the client Fig
12. ds to the name under which the OPC server is registered in the windows registry This function creates a new OPC server object or connects to an existing OPC server and returns the pointer to the corresponding interface Dim g pcServer As IOPCServerDisp Set g pcServer CreateObject LY ACC PAMISA OpcServer 20 Set g pcServer Nothing When the OPC server is no longer to be used the OPC server object must be released properly Setting the interface gOpcServer to Nothing terminates the OPC server provided that no OPC clients are connected Create Group To access the items a group must first be created using the method AddGroup of the OPC server interface A group is defined as a set of items and is identified by a PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Page 21 PAM ISA OPc DEMO Page 22 EXCEL SHEET APPLICATION unique name There are additional parameters passed to AddGroup like the activity flag and the update rate AddGroup returns on success an interface to the new created group object Dim gOpcGroup As IOPCItemMgtDisp Dim UpdateRate As Long Dim ServerHdl As Long UpdateRate 500 Set gOpcGroup gOpcServer AddGroup G1 True UpdateRate 1 0 0 ServerHdl UpdateRate If gOpcGroup Is Nothing Then MsgBox Error AddGroup End If Add Items Items can be added to the group using the method Addltems of the group interface A list of all item names is passed
13. e Manual Automatic or Record If the Manual refresh mode is selected the Refresh button is activated Each time the Refresh button is pressed all items displayed in the item list are read from the OPC server and the corresponding values are updated In the Automatic mode the OPC server informs the Excel sheet when a value has been changed and the items are kept up to date automatically The Record mode enables periodic recording of the item values displayed in the item list By selecting this option the Record chart is displayed and the Record button is activated Press this button to open a dialog for choosing the sample rate and to start the recording Chart The chart provides a graphical representation of values displayed in the item list Only values of the type number can be shown correctly There are two kinds of charts In the Manual and Automatic refresh mode a Column Chart is displayed This chart shows a vertical bar for each value where height corresponds to the item value PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Page 19 PAM ISA OPc DEMO Page 20 EXCEL SHEET APPLICATION In the Record refresh mode a Line Chart is displayed This chart contains a graph of each value displayed in the item list which shows the historical values of the item There are 100 samples recorded for each value The first sample always contains the latest value of an item The time base depends on the sample rate se
14. error Problem starting the watchdog thread 0x0D0300B Win32 client requesting an unknown variable 0x0D0300C Variable size mismatch 0x0D0300D Unable to access JTAG because of still active sessions 0x0D0300E JTAG is already being accessed 0x0D0300F JTAG access is not initialized 0x0D03010 Unable to initalize PAM application structures 0x0D0301 1 Internal error GetData failed 0x0D03012 Internal error Command interpreter Unknown command 0x0D03013 Internal error CHNL CMD DWNLOADBEG Type not supported 0x0D03014 Internal error Problem downloading data 0x0D03015 Pam gt PC Unknown DPID 0x0D03016 Internal error Unable to initialize the session manager 0x0D03017 Internal error Unable to initialize the session fifos 0x0D03018 Internal error Unable to go to the specified state 0x0D03019 PC gt Pam Dualport fifo full 0x0D0301A Pam gt PC Windows fifo full PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Page 25 APPENDIX A Page 26 0x0D03100 PC gt Pam Windows fifo full 0x0D03101 Internal error Not enough memory 0x0D03102 New application detected Variables list mismatch Restart the OPC server 0x0D03103 Unable to initialize communicate with the Pam ISA device driver 0x0D03104 0x0D03105 Internal error Unable to cre
15. ess mechanism using the PAM ISA Opc Server Version 1 0 xx A short introduction to the OPC concept at the beginning of this document will give the necessary background to understand how the OPC is used A demo application is provided in the last chapter to illustrate how the OPC mechanism can be used in practice A simple Excel sheet demonstrates the data access to PAM ISA information with the automation interface using Visual Basic Scope Prior knowledge about OPC is not required to read this document However this document gives a short overview of the OPC specification For detailed information about OPC please refer to the references listed belovv To understand the implementation part of the Excel demonstration sheet some programming experiences with languages like Visual Basic will be needed It is also necessary to have some basic knovvledge on the COM architecture to access OPC objects References Documents 1 OPC Data Access Custom Specification 2 0 OPC Foundation 1998 http www opcfoundation org 2 OPC Data Access Automation Specification 2 0 OPC Foundation 1998 3 Data sheet PAM ISA 006 8035 Atlas Copco Controls 1999 4 Inside COM Dale Rogerson Microsoft Press 1997 5 PAM Can Bus Interface User s Manual 006 8029 B Atlas Copco Controls 1997 6 PAM ISA Technical manual 006 8037 PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Page 5 INTRODUCTION REFERENCES Page 6 Glossary
16. ion D pamisa agl located under ACC pam isa must be first compiled After compilation download D_pamisa pai to the PAM ISA using PAM Tools Then start the PAM and check if the application is able to run The optical ring must be closed by a single fiber Typical log messages when application is correctly synchronized with the PAM ISA Opc Server 0B80M105 Start Synchronisation 0B80M106 Synchronisation is done 0B80M10C Channel Bootvare version Dl gesdp 1013 0B80M10D Channel Firmware version Dl gesdp 1013 0B80M10B Channel protocol Dl gesdp PC based channel 0B80M107 Valid Application Excel Sheet application The Excel sheet demo application D_pamisa xls illustrates how the PAM ISA Opc Server can be accessed in order to collect information from the PAM ISA device Because Visual Basic is used to access the automation interface of the PAM ISA Opc Server the Excel sheet must be opened with Macros enabled Connection The Excel sheet must be connected to the PAM ISA Opc Server before the PAM data can be accessed On the first line is listed the name of the PAM ISA Opc Server which is set to ACC PAMISA_OpcServer 20 by default To work with the PAM ISA Opc Server this name doesn t have to be changed But this could be the name of any OPC server installed on your machine Press the button Connect to open the connection If the connection is established the server name will be grayed and the button changes to Disconnec
17. lected in the record dialog PAM application The PAM demo application provided with the PAM ISA Opc Server has eight channel variables f the demo application has been downloaded eight items appear in the drop down lists of the item list in the Excel spreadsheet The item names are as follows Variable Name Item Name Description LRI_StartStop Commld 0x010 Start Stop demo application Default 0 LRI_Offset Commld 0x020 Phase offset in degrees added to the SinShiftValue Default 0 LRI Limit Commld 0x030 Max value for RampValue Default 0 gt not active LRI_ChangeRate Commld 0x040 Change cycle in milliseconds Default 10 LRI_IncrementSize Commld 0x050 Value with which the RampValue is incremented each cycle Default 0 1 LRO_RampValue Commld 0x100 incremented value Default 0 LRO SinValue Commld 0x110 sinus value Default 0 LRO_SinShiftValue Commld 0x120 sinus value shifted by offset Default 0 Table 5 SEQARABEChannel Variables Created by PAM Application This PAM application is a simple application which can be started and stopped with the variable LRI_StartStop When running the variable LRO_RampValue is incremented periodically then reset to zero when the limit LRI Limit is reached For the LRO_SinValue a sine signal is generated The same signal shifted by the value LRI_Offest is generated for LRO_SinShiftValue PAM ISA Opc Server User Ma
18. ms are updated and can be accessed only if they exist in at least one group em Figure 2 Group ltem Relationship An OPC server usually has multiple groups of two kinds private and public groups Private groups are visible to only one client whereas public groups can be used by all clients Interface Referring to the OPC server objects mentioned in the section above there is a well defined interface that can be used to access the server obiects This section provides a short overview of the interfaces provided by the OPC DataAccess specification For detailed information on these interfaces please refer to 2 Since the OPC specification is based on the COM architecture the interfaces defined for the OPC server objects represents interfaces to COM components Like any COM component OPC server objects also provide the lUnknown interface Beside this interface the following interfaces are defined PAM ISA Opc Server User Manual Page 8 DOC 006 8036 Rev May 22 2000 OPC NTERFACE Object Interfaces Server IOPCCommon IOPCServer IOPCServerPublicGroups IOPCServerBrowseServerAddressSpace IPersistFile IConnectionPointContainer IOPCServerDisp IOPCServerPublicGroupsDisp IOPCServerBrowseServerAddressSpaceDisp Group IOPCItemMgt IOPCGroupStateMgt IOPCPublicGroupStateMat IOPCSynclO IOPCASynclO2 IConnectionPointContainer IOPCItemMatDisp IOPCGroupStateMgtDisp IOPCPublicGroupSt
19. nual DOC 006 8036 Rev May 22 2000 PAM ISA OPc DEMO EXCEL SHEET APPLICATION Before starting the application the PAM should be reset To do this select the Reset item see SEQARABE and change its value to 1 All variables are now reset to their default values To start the application change the value of the item Commld 0x010 to a value not equal to zero e g 1 To stop the application set it back to zero Using the OPC automation interface vvith Visual Basic n this section the Excel sheet demo application vvhich is realized vvith the scripts language Visual Basic is discussed in more detail The aim of this section is to highlight some key points concerning the OPC automation interface Further documentation of the demo application can be found in the source code Detailed information concerning the OPC automation interface can be found in 2 In this example the automation interface version 1 0 of the OPC DataAccess specification is used This specification has changed significantly in version 2 0 and the procedure for accessing an item differs from the procedure described in this section General Before the OPC DataAccess automation interface can be used with Visual Basic make sure that the type library OCSTK 1 0 Type Library is selected in the reference list Connect To connect to the OPC server an appropriate COM object must be created using the function CreateObject The name passed to this function correspon
20. reset the PAM The PAM will be reset each time a value not equal to zero is written Write only variable State of the PAM device Read only variable Please refer to appendix A for details Number of SAM s connected to the PAM Read only variable PAM bootware date of creation Read only variable PAM boot ware version Read only variable PAM boot ware CRC Read only variable PAM firmware date of creation Read only variable PAM firm ware version Read only variable PAM firm ware CRC Read only variable PAM application name Read only variable PAM application date of creation Read only variable Page 13 PAM ISA OPC SERVER Page 14 Driver Error DESCRIPTION PAM application time of creation Read only variable PAM application version Read only variable PAM application CRC Read only variable Status of the PAM ISA windows driver Please refer to appendix A for details Error code of the PAM ISA windows driver Please refer to appendix A for details Systeminfo variables for SAM lt n gt connected to PAM lt n gt hex SAM address Sam lt n gt Parameters CRC SAM boot ware version Read only variable SAM boot ware CRC Read only variable SAM firm ware version Read only variable SAM firm ware CRC Read only variable SAM application version Read only variable SAM application CRC Read only variable SAM parameters version Read only
21. rir a 17 Demo Installation and Setup esse eee ee eee eee eee 17 PAM ISA software configuration 18 Excel Sheet application 2 8 8 s s ae eee eir aa ai isidir a33 18 CONNECTION cii ridad tdi dda 18 Description r b b Sn 19 PAM application 2 Y 20 Using the OPC automation interface with Visual Basic 21 Type conversion with Visual Basic eee eee 23 Appendix A daa 25 PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Page 3 TABLE OF CONTENTS Status and Error Codes ooccccccncncncicininncinnnnnncnonininininenenenenenenenenenenonenenenenenenenenenenos 25 fiver Stat s a r a UL m su DL A 25 DIIVer ETTOR caricia na id TT 25 Systainer ans 26 PAM ISA Opc Server User Manual Page 4 DOC 006 8036 Rev May 22 2000 Introduction The PAM ISA Opc Server is a common interface developed by Atlas Copco Controls to access the PAM ISA device from Microsoft Windows applications Its implementation is based on the OPC standard defined by the OPC Foundation Version 1 0 xx of the PAM ISA Opc Server handles data exchange between the PAM ISA device and Windows applications Future releases will enable more complex functionalities such as software download and upload Purpose This document presents an overview of how the PAM ISA device is accessed via the OPC server data acc
22. t The status changes to Ready To change the server name in order to connect to a different OPC server the Excel sheet has to be disconnected first Press Disconnect and wait until the status changes to Initialized PAM ISA Opc Server User Manual Page 18 DOC 006 8036 Rev May 22 2000 PAM ISA OPc DEMO EXCEL SHEET APPLICATION Description After the Excel sheet is connected to the OPC server the items can be accessed and displayed The demo sheet contains three parts to do so Item list e Refresh mode e Chart Item list The item list displays up to eight items For each item the name and the value of the corresponding PAM variable is shown The item can be selected from the combo box which displays a list of all items currently available The current item value is displayed in the second column This value can be changed if the item is writable To do so select the corresponding text field enter the new value and deselect the text field by selecting any cell in the excel sheet If the access permission is read only the value will be grayed and cannot be changed If the item value is an array of multiple values e g array of 8 bytes only one element of the array will be displayed The element to display can be selected with the spin box displayed next to the value Values of arrays cannot be changed although the access rights for the item would allow it Refresh mode There are three refresh modes possibl
23. to this method indicating the items which should be added to the group As a result a list of all item objects successfully added will be returned Dim itemIDs 1 As String Dim active 1 As Boolean Dim clientHandles 1 As Long Dim errors As Variant Dim serverHandles As Variant Dim itemObjects itemIDs 0 System Reset active 0 True clientHandles 0 1 gOpcGroup AddItems 1 itemIDs active clientHandles serverHandles errors itemObjects Null Null Null Read Write item value To read or write the values of an item the item objects returned by the method Addltems can be used Dim opcItem As OCSItem Dim value PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 PAM ISA OPc DEMO EXCEL SHEET APPLICATION Set opcItem itemObjects 0 if Not opcItem Is Nothing Then value opcItem value read item value opcItem value value write item value End If Callback registration If the OPC client wants to be informed if a value of an item changes a callback can be registered in the OPC server This is done by the method AddCallbackReference of the IOPCAsynclODisp interface A context id as well as a callback object has to be passed to this method The callback object must provide a method OnDataChange vvhich is called in case a item value changes If the OPC client doesn t want to be informed any more of a data change the callback reference can
24. ure 3 shows the components used to access the PAM ISA device via the PAM PAM ISA Opc ISA Opc Server Server system call Asa bus PAM ISA n Figure 3 PAM ISA Opc Server Architecture PAM ISA Opc Server User Manual DOC 006 8036 Rev May 22 2000 Page 11 PAM ISA OPC SERVER Page 12 DESCRIPTION The PAM ISA Opc Server is an out of process COM component that is started when the first OPC client tries to connect to the PAM ISA Opc Server During startup the PAM ISA Opc Server scans the PAM device for all available variables using the appropriate interface of the PAM Windows driver For each variable a corresponding item is created and stored in the cache This is done only once in the lifetime of the PAM ISA Opc Server If the number of variables in the PAM changes e g after downloading a new application the OPC Server must be terminated i e all OPC clients must disconnect from the OPC Server in order to reload the variables during the next startup Updating of item values is event driven If a variable changes the PAM informs the PAM ISA Opc Server which in turn updates the corresponding item The update rate defined by the OPC client is not considered in this case because PAM ISA s event driven concept keeps the item values always up to date The PAM ISA Opc Server 1 0 xx does not support software download to the PAM device Software downloads are done via the serial port using the PAM Tools
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