PI OPCTool User Guide
PI_OPCTool
User’s Guide
Version 2.2.1.0
Revision A
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|PI_OPCTool.doc |
Table of Contents
Introduction 1
Reference Manuals 1
Diagram of Hardware Connection 2
Principles of Operation 3
Installation 5
Starting PI_OPCTool 7
Connecting to an OPC Server 9
Connecting to an OPC Server on the Local Node 9
Connecting to an OPC Server on a Remote Node 9
Checking the Status of the OPC Server 10
Creating a Group 11
Adding Items to a Group 11
Displaying an OPC Server's Tags Automatically 11
Displaying an OPC Server's Tags Manually 12
Filtering Items 13
Adding an Item 13
Removing an Item 15
Reading Data 17
Executing Synchronous Read Operations 17
Executing Asynchronous Operations 17
Reading All Items in a Group 18
Reading One Item in a Group 18
Executing Advise Operations 19
Writing Data 21
Writing to an Array 21
Writing a Date or Time Value 22
Activating and Inactivating Items / Groups 23
Saving and Loading Configuration Data 25
Remote Operation 27
Technical Information 29
Troubleshooting 31
Introduction
OPC (OLE for Process Control) is a standard established by the OPC Foundation task force to allow applications to access process data from the plant floor.
OPC servers with communication interfaces that comply with the OPC Standard allow client software applications that follow this standard to communicate with any of those servers without regard to hardware releases or upgrades.
The connection between the client and the OPC server is either through the Microsoft COM interface or through OLE Automation, and the client accesses data from the data cache maintained by the OPC server or requests that the server read the device directly.
This PI_OPCTool uses an OPC COM custom interface to communicate with OPC servers. Use this tool to help configure and use the OSIsoft OPC Interface with the OSIsoft OPC Server or to check communications with any third-party OPC server.
This tool runs on NT platforms running NT4, Windows 2000, or XP.
The PI_OPCTool provides the following features.
• Connections to as many as five OPC servers.
• Creation of up to ten groups with up to 200 items per group.
• Synchronous read/write operations.
• Asynchronous read/write operations.
• Advise read operations.
• Tag filtering for refining the tags to be displayed and assigned as OPC items.
• Working configuration can be saved to files, to be used in creating PI tags and startup files for the PI OPC interface
This document describes the PI_OPCTool and how to use it to check communications with any Data Access version 1.0a or 2.0 OPC Server.
Reference Manuals
OSIsoft
• OPC Server Manual
• OPC Interface to the PI System
Vendor
The OPC standards are freely available from the OPC Foundation at .
Diagram of Hardware Connection
[pic]
Principles of Operation
This tool is designed to allow the user to validate data communication with an OPC server. It is not intended to be used to collect data for practical purposes, or as part of a functional application, nor is it intended to be used to configure PI tags on any extended basis. It is simply provided as a way to test the functionality of an OPC server, and to verify that network and application permissions are correctly set to allow communication between an OPC server and a client application.
Specifically, the tool will execute one method of the OPC Data Access specification when one button is clicked, wherever that is practically possible. For some functions, more than one call to the OPC server may be made when one button is clicked, for example: when connecting to the server, the tool will attempt to acquire several COM interface pointers, and will make several calls to the server. But overall, as far as possible, the rule is one click, one call. This is expressly intended to help in debugging problems in communicating with OPC servers, or to help in debugging the servers themselves.
There is no provision for storing data received from the OPC servers, or for sending data from a file or another program to an OPC server. This tool is for interactive use only.
Installation
The application does not require any installation. To use the online help, the help files (PI_OPCTool.hlp and PI_t) are required, but the only requirement for using the tool is the executable itself. The tool can run from a floppy or CD, if it is not on the hard disk.
The OPC proxy files must be installed on all machines, both client and server. These files can be obtained from the OPC Foundation, but both the client and the server probably include them in the installation.
This tool runs on NT platforms running NT4, Windows 2000, or XP.
Starting PI_OPCTool
To start the PI_OPCTool, simply double-click on the PI_OPCTool.exe file. The PI_OPCTool appears as shown below.
[pic]
Connecting to an OPC Server
The PI_OPCTool can connect to a server that runs on the local node or on a remote node. The PI_OPCTool can display the names of installed OPC servers. If the name of the OPC server of the local node is not present, make sure that the OPC server or its client package is installed on this node. If the OPC server runs on another node, use the OPC Enumerator to locate it, if OPCEnum is installed on both nodes (described in this section). The PI_OPCTool can connect to as many as five OPC servers.
Connecting to an OPC Server on the Local Node
To connect to an OPC server on the local node, follow the steps below.
1. Click as shown in the figure below to display a list of the OPC servers registered on the system.
[pic]
2. Select the appropriate server and then click Connect. For the local node, leave the Node Name field blank.
A message box appears to confirm a successful connection and the name of the connected server appears in the Connected Servers field.
Connecting to an OPC Server on a Remote Node
The OPC Foundation has provided the OPC Enumerator tool to help establish connections between clients and servers that are on separate nodes. To use the tool, it must be installed on both nodes. The install kit for the OSIsoft OPC Interface installs OPCEnum on the client node in the Winnt/System32 directory and also places a set of files in the OPCEnum directory under the directory in which the OPC Interface was installed. To install the tool on another node, copy the files from the OPCEnum directory to the node and register them by running Register.bat. Then, check the DCOM configuration for the OPC Enumerator.
To connect to a server on a remote node, follow the steps below.
1. Verify that the OPC Enumerator is installed on both nodes. Then, enter the node name in the Node Name field and click Connect. The PI_OPCTool will connect to the remote OPCEnum and get a list of the servers on the remote node.
2. Click as shown in the figure above to display a list of the OPC servers registered on the remote node.
3. Select the appropriate server and then click Connect again.
A message box appears to confirm a successful connection and the name of the connected server appears in the Connected Servers field.
Checking the Status of the OPC Server
To check the server status, follow the steps below.
1. Select the server in the Connected Servers field.
2. Click Server Status.
Information about the server appears in the Points field, as shown in the figure below.
[pic]
Creating a Group
Up to ten groups can be defined for each OPC server. Each group must have a different name, although the same name can be used on different servers.
To create a group for a server, follow the steps below.
1. Select the server from list of servers in the Connected Servers field.
2. Enter a name for the group in the Group field.
3. Enter an update rate in milliseconds in the Update Rate field.
This rate specifies how often the server will check for new values for the items in this group. The server may not be able to provide the requested update. If the actual rate is different, this value replaces the one that was entered.
4. To create the group inactive, check the box next to the Inactivate button. This box is only enabled when a new group name is entered. Once the group is created, the user can activate and inactivate it using the button.
5. Click Create as shown in the figure below.
A message box appears to confirm a successful creation of a group, and the group is added to the list of Groups on this server.
[pic]
Adding Items to a Group
Up to 200 items can be added to each group that is defined for an OPC server. Before adding items to a group, display the list of available tags on the server. Then choose the tags to monitor and add them to a group.
If the OPC server does not support browsing, the ItemIDs can be entered manually. Be aware that the ItemID has to exactly match what the server is expecting. This includes punctuation characters and upper or lower case of characters, and the full ItemID must be entered, which may consist of several segments.
Displaying an OPC Server's Tags Automatically
Depending on the capabilities of the server, all the tags on the server can be displayed in a flat or hierarchical format by clicking List Server's Tags. If the server's items are in a flat format, the tags appear as a simple list. If the server's items are in a hierarchical format, the list appears as a tree that can be expanded as needed.
To display all the tags on a server, follow the steps below.
Caution: Do not use List Server's Tags for DeltaV or PI OPC servers, or any other which is likely to have a great many items. "All the server's tags" can be hundreds of thousands, and the function may crash the application or simply take an hour or more to complete. Use Manual Tag List instead.
1. Select the server from list of servers in the Connected Servers field.
If the server has the capability of listing its items, the Browsable checkbox is checked. Otherwise, the server does not support this functionality.
2. Click List Server's Tags. The tags appear as shown in the figure below. If the list is in a hierarchical format, expand the branches as needed.
[pic]
Displaying an OPC Server's Tags Manually
The user can control how many tags that he/she wants the server to display. This is particularly useful if there are very many tags, which can take many minutes to display.
The Manual Tag List button displays one level of a hierarchical tree. Select either Branches, Leaves, or a Flat view of the item list. Leaves are Items that can be added to a group. Branches can have Leaves under them, and they can also be items themselves. A Flat view displays all Leaves below the selected Branch in a simple list.
If no displayed Item or Branch is selected, the tool will operate from the root of the server's Item tree. If a branch is selected, then the requested operation will be carried out at that position. This allows the user to first get a listing of the branches at the root level, then select a branch and proceed downward into the branches and leafs below that branch. If a Flat view is selected and a branch is selected, the tool will get a list of all the leaves below that selected branch.
The tags appear as shown in the figure below.
[pic]
Filtering Items
Filter by selecting for Input/Output Items, or (if the server supports it) by specifying a server-specific filter string.
To filter the tags based on Input/Output :
1. Select the server in the Connected Servers field.
2. If the server has the capability of listing its items, the Browsable checkbox is checked. Otherwise, the server does not support this functionality.
3. Choose to display a Branch, Leaf, or a Flat view of the item list.
4. Select the Input (for all readable tags) or Output (for all writeable tags) checkboxes to select all readable or all writeable tags, respectively. Both boxes can be checked to list only items that are both readable and writable.
5. As described above, either click List Server's Tags, or choose a branch and click Manual Tag List.
To filter using server-specific strings:
1. Select the server in the Connected Servers field.
2. If the server has the capability of listing its items, the Browsable checkbox is checked. Otherwise, the server does not support this functionality.
3. Choose to display a Branch, Leaf, or a Flat view of the item list.
4. Enter the filter string in the Filter box. These strings are free-form, and each server which supports filtering will have its own format for what can be put into the filter string.
5. As described above, either click List Server's Tags, or choose a branch and click Manual Tag List.
[pic]
Adding an Item
After the tags are displayed, choose the ones to add as items to a group.
To add the tags on a server to a group, follow the steps below.
1. Select the server in the Connected Servers field.
2. Select the group in the Group field the item will be added to.
3. (a) If the server supports browsing, double-click the item in the browse tree, and the full ItemID of the Item will be copied to the Item field. The PI_OPCTool also adds the item to the Tag field, with the group name pre-pended. Edit the TAG field to make sure the tag name is unique.
OR
(b) If double-clicking the tag name does not add the item to the Item field, enter the item name manually. Enter a tag name in the Tag field as well.
Note: The Tag field is only a temporary name for this Item in this group. The same Item can be added to a group more than once, the same Item can be added to multiple groups. But each Item that is added to a group must have a unique Tag name. This tag has nothing to do with PI Tags, unless the configuration is saved and used it to create PI tags. The tag could be named "Fred"; it doesn't matter, as long as there's not already a "Fred" tag in the group.
4. Click Add to Group to add the item to the group.
A message box appears to confirm the successful addition of the Item to the group, and the item appears in the Points field as shown in the figure below.
[pic]
Removing an Item
To remove an item, enter its name in the Tag field (double-click the item in the Points field instead) and click Remove from Group, as shown below.
[pic]
Reading Data
The PI_OPCTool can do synchronous and asynchronous read operations and both can be used to test communications with the server. However, the fact that the PI_OPCTool can do a synchronous read operation on the server does not mean that the OPC Interface (or third-party client) can also read data. The OPC Interface makes asynchronous calls to read data, because they are faster. Verify that data can be read with the PI_OPCTool using a refresh, asynchronous read, or advise operation, all of which are asynchronous calls.
Executing Synchronous Read Operations
To do a synchronous read operation, follow the steps below.
1. Select the server in the Connected Servers field.
2. Select the group in the Group field containing the items to be read.
3. Click SyncRead, as shown below. The current values for all items in the group appear in the Points field.
[pic]
Executing Asynchronous Operations
Asynchronous operations can be done on individual items or on all items in a group. The Advise function can also be used to ask that the server send new data as it becomes available. The OSIsoft OPC Interface makes asynchronous calls. Therefore, it is important that the user verify that data can be read with the PI_OPCTool using a refresh, advise, or asynchronous read, which all operate asynchronously. What that means is that the tool makes a request, and sometime later, the server initiates a call to the tool, with either the data or the error code if the operation failed. To make that callback, the server has to have permission to initiate the conversation with the tool, or with the PI interface. Performing an asynchronous operation with the tool will verify that the DCOM permissions are set up properly and the server has the necessary permissions to initiate a conversation with the client.
The OSIsoft OPC Interface makes asynchronous read calls for triggered read operations, when the change of a value in PI triggers a request for the current value of an item. It uses Refresh calls to poll for values, and most common and most efficient, it uses Advises to have the server send new values as they become available.
Reading All Items in a Group
To do a Refresh operation on a group, follow the steps below.
1. Select the server in the Connected Servers field.
2. Select the group in the Group field containing the items to be read.
3. Click Refresh (either Version 1.0 or 2.0) as shown below. The current values for all items in the group appear in the Points field.
[pic]
Reading One Item in a Group
To do an asynchronous read operation on one item in a group, follow the steps below.
1. Select the server in the Connected Servers field.
2. Select the group in the Group field containing the items to be read.
3. Select the tag to read. Either double-click the tag in the server list field or enter the name in the Tag field.
4. (a) Version 1.0: Click AsyncRead. The current value for the selected item is displayed in the Points field.
If Device Read is selected before AsyncRead is clicked, then the value is read from the device. If Device Read is deselected before AsyncRead is clicked, then the value is read from the server's cache.
(b) Version 2.0: Click AsyncRead. The current value for the selected item is displayed in the Points field. All values are read from the device. There is no effect if the Device Read checkbox is checked.
//
Executing Advise Operations
To do an advise operation, follow the steps below.
1. Select the server in the Connected Servers field.
2. Select the group in the Group field containing the items to be read.
3. Click Advise, (either Version 1.0 or 2.0). The current values for all the items in the group appear in the Advise Data field, as shown below.
[pic]
The server continues to send data as it becomes available until UnAdvise is clicked (with the appropriate server and group selected), or until the group is deleted, or disconnected from the server.
Writing Data
The PI_OPCTool can do synchronous and asynchronous write operations, and both can be used to test communications with the server. However, just because the PI_OPCTool can do a synchronous write operation on the server does not mean that the OPC Interface (or third-party client) can also write data. The OPC Interface makes asynchronous calls to write data, because they are faster. Verify that asynchronous write operations can be done with the PI_OPCTool.
To write data with the PI_OPCTool, follow the steps below.
1. Select the server in the Connected Servers field.
2. Select the group in the Group field containing the items that to be read.
3. Double-click the point in the Points field to which data should be sent. Or, enter the name of the point in the Tag field.
4. Enter a value in the Value field, select the type of write operation (Synch, Asynch 1.0, or Asynch 2.0), and click Write as shown below. The new value for the point appears in the Points field. If the group is set to advise, the new value also appears in the Advise Data field, as shown in the figure. The data type might need to be specified using the dropdown list of available data types. It's always safest to use the data type that the server itself uses for the data, if possible, but the server should transform the data type if it can be done.
[pic]
Writing to an Array
To write to an array tag, select the array type and then enter the values in the Value field. Separate each value with a comma. The values will be assigned to the array elements in order. It is not possible to skip an element and then write to elements that come after it in the array.
Writing a Date or Time Value
To write to a VT_DATE item, use the following format.
ccyy/mn/dd hh:mm:ss.000
This is the only valid format for the PI_OPCTool.
For example, write the following date values.
1998/11/29 15:43:22.902
1998/11/29 15:43:22
Activating and Inactivating Items / Groups
Each configured OPC group and each item is created in the server in an initially activated state. Use the active flag of a group or item, along with the update rate, to reduce resources used by clients and servers. These attributes affect how often data and quality information is updated and how often calls are made to the client.
The expected operation by servers and clients is beyond the scope of this user guide. Refer to the OPC Data Access Custom Interface Standard Version 2.05 for detailed information. For general testing of communications with the server, it is recommended to leave groups and items in the activated state.
To inactivate groups or items, select the group or item and click Inactivate.
After clicking Inactivate the button changes to Activate which can be clicked to reactivate objects.
Saving and Loading Configuration Data
The PI_OPCTool supports saving configuration data to files.
• The Opcint.bat file is a template batch file that can be used to start the OPC Interface based on settings selected with the PI_OPCTool.
• The tag configuration file contains the defined groups and the items that were added to them. It is a comma-separated variable (CSV) file and it can be imported it into a spreadsheet to use with PI-SMT (the PI System Management Tool) or edit directly and use it as input to PICONFIG.
Load these files into the PI_OPCTool to avoid having to redefine groups and items.
To save configuration data, follow the steps below.
1. Select the server in the Connected Servers field.
2. Click Save.
3. In the dialog box that appears, enter a file name for the Opcint.bat file in the top field and a file name for the group/item configuration data in the bottom field. Then click OK. The data is saved in the files specified.
[pic]
To load the configuration data, follow the steps below.
1. Start the PI_OPCTool.
2. Click Load.
3. In the dialog box that appears, enter a file name for the Opcint.bat file in the top field and a file name for the group/item configuration data in the bottom field. Then click OK. Configuration data is loaded into the PI_OPCTool.
Remote Operation
The OPC Server can be located on a different node from the OPC client. For this remote operation, verify that DCOM settings are correct on the local and remote nodes. For detailed instructions, refer to the documentation that accompanies the server. Be sure to see the user manual for the OSIsoft OPC Interface, which has detailed information about configuring DCOM.
Technical Information
In general, the tool is designed to execute one OPC method at a time. Wherever possible, when a button is pressed, one call is made to the OPC server. Of course, there's a compromise between usability and simplicity, so there are buttons which execute multiple commands, namely the commands which actually read and write data. When a Refresh or Read button is clicked, the tool will ask for the appropriate interface pointers, if it doesn't already have them, execute the requested operation, and finally it will release the pointers. The exception to this is the case where the group is advised. If the group has an Advise active, the asynchronous operation does not require any more interface pointers to be acquired, and the tool does not release the pointers after the operation is complete. The pointers are released when Unadvise is called. This is, of course, on a per-version basis, so if a group has a Version 1.0a Advise active, that will have no impact on what the tool does for a version 2.0 Refresh: the tool will acquire, use, and release the v2.0 interface pointers.
This tool is not intended to be a complete implementation of the OPC Data Access standard, but it exercises most of the features of the server, and all of the features which are used by the PI OPC Interface.
Troubleshooting
When working with the PI_OPCTool, some of the problems listed in this section may be encountered. For severe problems, contact OSI Tech support (if trying to set up an OSI product) or the OPC server vendor.
Fail to Receive Data from Refresh or Advise
If data cannot be retrieved using the Refresh or Advise features, but it comes in while doing a synchronous read operation, it is likely there is a permission problem in the DCOM configuration. Check the DCOM permission settings.
Unable to Get IOPCServer Pointer
The server would not provide a pointer to its IOPCServer interface. This is a severe problem that makes the server unusable.
Unable to Get IOPCBrowseServerAddressSpace Pointer
The server does not support the listing of its items. Enter item names manually.
Unable to get IOPCGroupStateMgt Pointer
This means the group's update rate can not be changed, or flag the group as active or inactive. The server is broken, but probably somewhat usable.
Unable to Use IUnknown Pointer
This is a severe error, and means that the server is not usable.
Unable to Use IOPCServer Pointer
This is a severe error, and means that the server is not usable.
Unable to Set Group State
The server failed to set the group state as requested. This means the update rate cannot be changed, or flag the group as active or inactive. The server is broken, but probably usable.
Unable to Get Browse Type
The server says it supports browsing, but won't publish whether it has a hierarchical or flat namespace. The server is broken but probably usable. Enter item names manually.
//
Unable to Get Status
We asked the server to report its status, and it refused. This is a Bad Thing, since this is required functionality for an OPC server. The biggest problem it will present is that this is the only way to ask the server for its local time. The server is still usable, but server timestamps aren’t available.
Unable to Get Group State
We asked the server to tell the state of a group, and it refused. This is a Bad Thing, since this is required functionality for an OPC server. The biggest problem it will present is that the update rate can’t be changed or the active/inactive flag for the group. Talk to the server vendor.
Unable to Find Server
The operating system does not have a server registered under the name that was entered. Verify that the server name was entered correctly. In order to connect to a server running on a remote node, the server must be registered on the local node. Not all servers can be run remotely. Refer to the documentation for the OPC server for instructions about how to handle this.
Unable to Connect to Server
The PI_OPCTool is unable either to locate the specified node, or unable to find the specified server on that node. If a node name was specified, try opening a DOS window and entering ping xxx, where xxx is the name for the remote node. If a proper response is received, the local node is able to communicate with the remote node.
If the node is located, verify that the server has been installed on the remote node. As a last resort, try rebooting the remote node. If the last client to communicate with the server failed to disconnect properly, the server may require restarting. Rebooting the node is the safest way of shutting down the server, unless the server documentation has other instructions. The client requesting a connection will restart it. Be aware that some servers require a manual startup before any client tries to connect.
If the server came with a simple sample client, as many do, try using that client to connect.
Unable to Get IUnknown Pointer
This is a severe error, and means that the server is not usable.
Unable to Add Group
The server failed to add a group. The error message may explain why. If not, check the following.
• Is there a group by that name already defined for this server?
• Have more groups been added than the server supports?
• Was an Update Rate entered?
//
Unable to Browse Items
The server claims to support browsing, but it's broken. It is probably still usable, but item names will have to be entered manually.
Unable to Change Browse Position
The server claims to support browsing, but it's broken. It is probably still usable, but item names will have to be entered manually.
Unable to Get Full Name
The server was asked for the complete Item name for an item, and returned an error. Enter various name combinations to see if the server can recognize them. If a server is using a hierarchical structure for its item list, the full name of the item may be a concatenation of the names of the branches. If the leftmost branch A1, for example, and the next branch is B2, and the final leaf is C4, the name of the item at C4 might be one of the following.
• A1.B2.C4
• A1/B2/C4
• A1-B2-C4
• A1_B2_C4
Try any of these name combinations, and if they do not work, consider other alternatives. And call the server vendor to tell them that the server is broken.
Unable to Add Item to a Group
The server failed to add an item to a group. Usually the server will explain why, and the error message will include the extra information. Some of the more frequent reasons:
• The group already has as many items as the server allows.
• The server does not recognize the item name as a valid name.
• The item cannot be returned with the selected data type. Try another data type.
• The server requires an access path. This is illegal, but at least one server has implemented that requirement. It was fixed by adding the access path information to the ItemID.
If the problem and the solution are not apparent from the error message, talk to the server vendor to see why the server is refusing the request.
Server Returns an Invalid Data Type
This is a last-chance check after adding an item. The server is supposed to return a "server handle", which is the ID the tool will use to read or write the data, and it also returns the canonical data type (the data type that the server itself uses for this data item). Some servers don't return an error when they don't like the item added to the group, they just return junk. So a check is done to make sure that the canonical data type makes sense. Usually when the "server handle" doesn't make sense, neither does the canonical data type.
It's anybody's guess as to what the server disliked about the item the user tried to add. Ask the server vendor.
//
Unable to Remove Item
The PI_OPCTool told the server to remove an item from a group, and it returned an error. The error message may give more information. This is not a serious problem, most likely: in most cases, either the group is being deleted anyway, or the server has dropped the connection and the group doesn’t exist anymore anyway. But if the server won’t allow the removal of items from the groups, this is very bad behavior. Talk to the server vendor. If the error comes when the server has died or the network connection has disappeared, don't worry about it.
Unable to Write Value
The server returned an error when the PI_OPCTool tried to write to the item. Most often this is caused by a server not reporting that the item is not writable. If a read does not produce a W in the left-hand column, the server is not saying that the item is writable. There are other possible reasons why the server would refuse a write, but if an item can be added to the group and read, this is the most likely reason.
Revision History
|Date |Author |Comments |
|14-Aug-02 |CGoodell |Reformatted version 1.0.1 |
|15-Aug-02 |CGoodell |Fixed headers & footers |
|15-Aug-02 |ACraven |Added platform info |
|15-Aug-02 |CGoodell |Removed part number |
|28-Apr-03 |ACraven |Updated version numbering to #.#.#.# |
|27-May-2003 |ACraven |Fixed title page version number |
|4-Sept-2003 |ACraven |Updated picture for Get Position, up version. |
|17-Nov-2003 |ACraven |Updated version |
|14-Apr-2006 |Janelle |Version 2.2.1.0, Revision A: updated How to Contact us page; fixed|
| | |headers, updated Table of Contents, removed first person |
| | |references |
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