frank.seipel

arj3090: Thanks for the quick response.  AdvancedHMI is great, it even has an Ethernet driver for Logix, etc, and I have used it.  However, I'd prefer this solution work through a web browser.  

Good Morning, I need to write a STRING type tag to a ControlLogix PLC via a web browser so lab personnel can tag contents of various storage tanks approved including the date, their initials, etc.  I wrote a simple VBSCRIPT, below, to achieve this using OPC to RSLinx Gateway 2.5x running on the same PC as this script, and it works fine when I double click it, to either read OR write the PLC tag, without any Matrikon or other 3rd party software.  Note that it reads/writes to a string array, a fixed value, to a SINGLE array element -- as this is just a test -- once I have it working I will tie it into a web input form. Please bear in mind, this computer handles datalogging and a number of other tasks running under RSVIEW32 7.40, thus it is Windows XP and II 5.1.  I cannot upgrade to newer windows at this time due to cost.  It also handles web-based plotting using Dygraphs and Oracle mySQL, so IIS is already set up on the PC.  I even have Excel functions written to query the Oracle MySql server to look up averages and tag values (poor-man's OSI PISOFT). The problem is, when I try to run the script from a web browser, as I need to do, it throws an error on the Set objOPCServer = CreateObject("OPC.Automation") line.  The error is below: Microsoft VBScript runtime (0x800A01AD) ActiveX component can't create object I assume this is some sort of DCOM permissions error; but I tried to set script/directory permissions to an Administrator account and it STILL did it.  This web site ONLY functions on a plant LAN, I'm not terribly concerned about security.  If someone could tell me how to remedy this, it would be very helpful.  Or if they could provide a free alternative way to achieve the tag write within a web browser, that would be great.  Obviously, it does NOT throw this error when I double-click the same script within Windows logged in under Administrator account. Also, I ALREADY have a 1756-eWeb ControlLogix card, and use it to read PLC values to web pages; however, I cannot use WriteLogixTag because it appears only to allow me to write values to a CPU in the same SLOT as the eWeb card; since it's on a different rack, and I cannot move it, that is NOT an option.  It MIGHT be possible to use CIP Generic message on the eWeb, but I don't know enough about CIP, to build a command that would write a string tag -- so alternately if someone can provide a simple example of that it would prove invaluable.  I do NOT understand why Allen-Bradley's eWeb ReadLogixTag function ACCEPTS a full path but WriteLogix only takes a 'slot' as a parameter... If there is an easier way or alternate script language means of writing a tag than what I'm doing below, I am open to that as well.  I think this might be useful to others as a free way to view plant data on a web page WITHOUT any 3rd party products (even without an eWeb card) if this minor issue could be overcome. . .   <%@ Language= "VBScript" %> <% response.write("Hello world! - VBScript in IIS") 'Define variables Dim objOPCServer Dim objOPCGroup Dim objOPCItem1 Dim vItem Dim vQuality 'make reference to RSLinx OPC Automation Interfaces dll and Create OPC Server object Set objOPCServer = CreateObject("OPC.Automation") 'Connect to RSLinx objOPCServer.Connect "RSLinx OPC Server", "" 'Define OPC Server parameters objOPCServer.OPCGroups.DefaultGroupIsActive = True objOPCServer.OPCGroups.DefaultGroupUpdateRate = 300 'Create OPC Group Set objOPCGroup = objOPCServer.OPCGroups.Add("VSE") 'Add OPC item to read 'The code below assumes that opc item 'TANK_CONTENTS_ARRAY' resides on OPC topic 'Heartland' Set objOPCItem1 = objOPCGroup.OpcItems.AddItem( "[Heartland]TANK_CONTENTS_ARRAY[0]", 1) objOPCItem1.Read CLng(0), vItem, vQuality objOPCItem1.Write ("TEST_STRING_CONTENTS") 'msgbox "The Value Is: " & vItem %>