OPC

OPC (OLE for Process Control).

Printfaqtory is a full OPC 2 compliant server that is, without doubt, THE easiest to configure OPC Server available. A normal OPC configuration requires you to define each Tag individually, a lengthy and error prone task for several thousands of tags (or even 10). With PrintFaqtory, you just identify the column that contains the Tag names and the tags are created for you automatically, grouped under the name of the Report. And that’s not all. If you follow the OPC standard of the “.” notation in your Tag names then all your sub groups will be created automatically also. This interface is only relevant for Tag based reports from a PLC or DCS.

Below is an example of a Tag Report that once defined in PrintFaqtory (click here for an example), will generate the OPC Tags on the first printing of the report and then update the Tags on subsequant prints. If enabled, a record of each Tags value is kept in a history table for Historical Analysis.

After the above report has been defined in PrintFaqtory (click here for an example) and printed, selecting the ‘Extracted Data’ tab displays the result of the print processing for diagnostic purposes i.e. for checking that the Document Header and Line definitions are correct.

If all is well with the Header/Line definitions, then the Tag data is available to OPC Clients. Below is an example of Matrikon’s OPC Explorer connected to PrintFaqtory.

PrintFaqtory also has the ability to export the Tag database to a comma delimited text file (.csv) for importing the Tags into OPC Clients or editing in Excel. From PrintFaqtory's main menu, select File>Export Tag Database.

The OPC Client’s Add Tag screen above shows how PrintFaqtory has automatically generated the Tag Groups. Note, although Write Access is enabled, PrintFaqtory will (of course) ignore OPC writes. Below is the OPC Client display of the Tags.

DCOM (Distributed COM) configuration.

All OPC servers are DCOM applications and can be called by remote PCs over the network. DCOM requires configuring by dcomcnfg.exe (from PrintFaqtory’s main menu, Setup>DCOM Configuration). DCOM configuration is very much a blackart with unexpected consequences of innocuous configuration changes. For any OPC Server, not just PrintFaqtory, the only DCOM configuration that works 100% is to have the OPC Server PC and the OPC Client PC logon to a NT/WIN2K/XP domain with the same user ID. This allows the OPC Client PC to start (and re-start) the OPC Server. The OPC Server must then be configured by dcomcng.exe to set the User Account to the Interactive User. This allows PrintFaqtory’s interface to be visible when the PrintFaqtory OPC Server is started, remotely, by an OPC Client (if this is not set then the PrintFaqtory OPC Server will run on the target machine but without any indication to the user that it is running).

Before a remote OPC Client can connect to the PrintFaqtory OPC Server, it will require the registry entries for the OPC Server. These are located in the PrintFaqtory installation directory as ‘PrintFaqtory OPC Client.reg’. Double-click this file (from the client) to update the client’s registry (or download it from here).

DCOM Configuration. Step 1. From PrintFaqtory’s main menu, select Setup>DCOM Configuration. Scroll down to the ‘PrintFaqtory.OPC’ entry and click the Properties button. The PrintFaqtory.OPC Properties screen below opens.

Step 2. Click on the ‘Identity’ tab and select the ‘Interactive User’ Option button. Click on OK to close this screen and click OK again to close dcomcng.exe. PrintFaqtory will now run with the full user interface, if started by a OPC Client on a remote PC.

Of course if you don’t want the users to have the ability to change the PrintFaqtory configuration, select ‘This user’ and enter a UserID that is not available to your users (Administrator is recommended).