Q.: What are the limitations of OPC Time Monitor demo version?
A.: The demo version only provides valid data for 1 hour since server started.
Q.: Is OPC Time Monitor compliant with the OPC specifications?
A.: OPC Time Monitor successfully passes OPC Data Access Compliance Test 1.1.
Q.: For connections that OPC Time Monitor makes to my servers, I need to set up a special security for DCOM. It seems that settings made directly in registry or via DCOMCNFG have no effect on OPC Time Monitor. What is wrong?
A.: OPC Time Monitor sets its own security (technically speaking, it calls CoInitializeSecurity). For most situations, this should work fine. With some servers (WonderWare) or with certain network configurations it may, however, be necessary to tweak the security even more.
In order to allow the DCOM security for OPC Time Monitor be configured via DCOMCNFG, use REGEDIT tool to add a DWORD value UseCustomSecurity = 0 under HKEY_LOCAL_MACHINE\SOFTWARE\OPC Labs\Time Monitor.
Q.: When I am browsing the OPC Time Monitor from my client, I do not see the $CurrentValue and PreviousValue nodes, or my client refuses to add them into its configuration. How can I make them work?
A.: Some clients have problems with items that claim a canonical data type VT_EMPTY. $CurrentValue and PreviousValue are special nodes because their type depends on the server the value comes from, and this data type may not be known to OPC Time Monitor upfront. To resolve this (starting with Build 3058), you can configure a "Requested Data Type" in the configuration tool for every time topic. This setting controls both how the OPC Time Monitor requests the value from the server, and also how it presents the $CurrentValue and PreviousValue to its clients.