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OPC Toolbox 2.1.4
Managing OPC Toolbox™ Objects
This example shows you how to manage OPC Toolbox™ objects.
Contents
Step 1: Find OPC Toolbox™ Objects in Memory
You use the opcfind function to find OPC Toolbox objects in memory.
opcfind
ans =
[]
Create some OPC Toolbox™ objects
da = opcda('localhost', 'Dummy.Server.1'); grp = addgroup(da); itm1 = additem(grp, 'Fake.Item.ID1'); itm2 = additem(grp, 'Fake.Item.ID2');
Find all valid objects
allOPC = opcfind
allOPC =
[1x1 opcda] [1x1 dagroup] [1x1 daitem] [1x1 daitem]
The information is returned in a cell array, because opcfind can locate different objects. To access an object, use cell indexing.
newGrp = allOPC{2}
newGrp =
Summary of OPC Data Access Group Object: group1
Object Parameters
Group Type : private
Item : 2-by-1 daitem object
Parent : localhost/Dummy.Server.1
Update Rate : 0.5
Deadband : 0%
Object Status
Active : on
Subscription : on
Logging : off
Logging Parameters
Records : 120
Duration : at least 60 seconds
Logging to : memory
Status : Waiting for START.
0 records available for GETDATA/PEEKDATA
To find objects with a specific property, pass property/value pairs to the opcfind function.
allDA = opcfind('Type', 'opcda')
allDA =
[1x1 opcda]
Step 2: Remove Objects From Memory
To delete an OPC Toolbox object from memory, use the delete function with the object. Deleting a client object deletes all group and item objects associated with the client. Deleting a group deletes all items in that group.
delete(grp)
Find all remaining valid objects.
allOPC = opcfind
allOPC =
[1x1 opcda]
Using the delete function with the object will remove the object from the OPC Toolbox engine but not from the MATLAB® workspace. To remove an object from the MATLAB workspace use the clear function. To see what objects are in the MATLAB workspace, use the whos function.
Display the current workspace.
whos
Name Size Bytes Class Attributes OPCBlksTutorial_Scope 1x1 1866 struct accessRights 1x1 560 struct allDA 1x1 690 cell allID 1x1 110 cell allMdlFiles 2x1 918 struct allOPC 1x1 690 cell allServers 1x1 110 cell ans 0x0 0 double badInd 600x1 600 logical canDT 1x1 562 struct clientName 1x35 70 char da 1x1 630 opcda events 1x2 1290 struct exEvtTime 20x1 160 double exItmId 1x3 252 cell exQual 20x3 5760 cell exTStamp 20x3 480 double exVal 20x3 480 double grp 1x1 630 dagroup hostInfo 1x1 1120 struct isBadQual 600x3 1800 logical isRepeatQual 600x3 1800 logical itm1 1x1 630 daitem itm2 1x1 630 daitem itmIDs 1x2 184 cell k 1x1 8 double logDuration 1x1 8 double logEvtTime 600x1 4800 double logIDs 1x3 306 cell logQual 600x3 172778 cell logRate 1x1 8 double logTime 600x3 14400 double logVal 600x3 14400 double loggingDuration 1x1 8 double loggingSeconds 1x1 8 double mDir 1x48 96 char mI 1x1 8 double mdlDir 1x61 122 char mdlPubDir 1x59 118 char newGrp 1x1 630 dagroup ns 3x1 29452 struct numRecords 1x1 8 double oldDir 1x59 118 char options 1x1 130 struct opts 1x1 719 struct pI 1x1 8 double pubMFiles 9x1 3209 struct r 1x1 752 struct realItems 21x1 2060 cell recAvail 1x1 8 double repInd 600x1 600 logical sFirst 20x1 29768 struct sPeek 1x1 1610 struct sReal8Disk 40x1 31328 struct sawtoothItems 10x1 1044 cell statusInfo 1x1 838 struct stopdata 1x1 452 struct thisMFile 1x20 40 char thisName 1x15 30 char thisPath 0x0 0 char tout 51x1 408 double triangleItems 10x1 984 cell vals 1x2 16 double
Since an object was deleted, it is no longer valid.
grp
grp = Invalid dagroup object. This object should be removed from your workspace using CLEAR.
The items contained by that group are also invalid
itm1
itm1 = Invalid daitem object. This object should be removed from your workspace using CLEAR.
Clear the associated variables.
clear grp itm1 itm2
Display the current workspace.
whos
Name Size Bytes Class Attributes OPCBlksTutorial_Scope 1x1 1866 struct accessRights 1x1 560 struct allDA 1x1 690 cell allID 1x1 110 cell allMdlFiles 2x1 918 struct allOPC 1x1 690 cell allServers 1x1 110 cell ans 0x0 0 double badInd 600x1 600 logical canDT 1x1 562 struct clientName 1x35 70 char da 1x1 630 opcda events 1x2 1290 struct exEvtTime 20x1 160 double exItmId 1x3 252 cell exQual 20x3 5760 cell exTStamp 20x3 480 double exVal 20x3 480 double hostInfo 1x1 1120 struct isBadQual 600x3 1800 logical isRepeatQual 600x3 1800 logical itmIDs 1x2 184 cell k 1x1 8 double logDuration 1x1 8 double logEvtTime 600x1 4800 double logIDs 1x3 306 cell logQual 600x3 172778 cell logRate 1x1 8 double logTime 600x3 14400 double logVal 600x3 14400 double loggingDuration 1x1 8 double loggingSeconds 1x1 8 double mDir 1x48 96 char mI 1x1 8 double mdlDir 1x61 122 char mdlPubDir 1x59 118 char newGrp 1x1 630 dagroup ns 3x1 29452 struct numRecords 1x1 8 double oldDir 1x59 118 char options 1x1 130 struct opts 1x1 719 struct pI 1x1 8 double pubMFiles 9x1 3209 struct r 1x1 752 struct realItems 21x1 2060 cell recAvail 1x1 8 double repInd 600x1 600 logical sFirst 20x1 29768 struct sPeek 1x1 1610 struct sReal8Disk 40x1 31328 struct sawtoothItems 10x1 1044 cell statusInfo 1x1 838 struct stopdata 1x1 452 struct thisMFile 1x20 40 char thisName 1x15 30 char thisPath 0x0 0 char tout 51x1 408 double triangleItems 10x1 984 cell vals 1x2 16 double
To remove all OPC Toolbox objects from the engine and to reset the toolbox to its initial state, use the opcreset function.
Note: Using the opcreset function will only delete objects from memory, not clear them from the MATLAB workspace.
opcreset
Verify that no objects remain.
allOPC = opcfind
allOPC =
[]
Variables associated with deleted objects still remain.
whos
Name Size Bytes Class Attributes OPCBlksTutorial_Scope 1x1 1866 struct accessRights 1x1 560 struct allDA 1x1 690 cell allID 1x1 110 cell allMdlFiles 2x1 918 struct allOPC 0x0 0 double allServers 1x1 110 cell ans 0x0 0 double badInd 600x1 600 logical canDT 1x1 562 struct clientName 1x35 70 char da 1x1 630 opcda events 1x2 1290 struct exEvtTime 20x1 160 double exItmId 1x3 252 cell exQual 20x3 5760 cell exTStamp 20x3 480 double exVal 20x3 480 double hostInfo 1x1 1120 struct isBadQual 600x3 1800 logical isRepeatQual 600x3 1800 logical itmIDs 1x2 184 cell k 1x1 8 double logDuration 1x1 8 double logEvtTime 600x1 4800 double logIDs 1x3 306 cell logQual 600x3 172778 cell logRate 1x1 8 double logTime 600x3 14400 double logVal 600x3 14400 double loggingDuration 1x1 8 double loggingSeconds 1x1 8 double mDir 1x48 96 char mI 1x1 8 double mdlDir 1x61 122 char mdlPubDir 1x59 118 char newGrp 1x1 630 dagroup ns 3x1 29452 struct numRecords 1x1 8 double oldDir 1x59 118 char options 1x1 130 struct opts 1x1 719 struct pI 1x1 8 double pubMFiles 9x1 3209 struct r 1x1 752 struct realItems 21x1 2060 cell recAvail 1x1 8 double repInd 600x1 600 logical sFirst 20x1 29768 struct sPeek 1x1 1610 struct sReal8Disk 40x1 31328 struct sawtoothItems 10x1 1044 cell statusInfo 1x1 838 struct stopdata 1x1 452 struct thisMFile 1x20 40 char thisName 1x15 30 char thisPath 0x0 0 char tout 51x1 408 double triangleItems 10x1 984 cell vals 1x2 16 double
Step 3: Clean Up
Clear any remaining variables associated with deleted objects.
clear da newGrp allOPC allDA
