Writable/readable status

Allowlist entries control whether a point is writable, in addition to granting access to database points, thereby allowing projects broad control over the way distinct Open Platform Communications (OPC) Server instances interact with the RealTime database (RTDB).

Points in the RTDB that do not appear in the allowlist, can not be read or written to.

Each allowlist entry contains:

• The table in which the point is located.

• The point name.

• The writable status.

A point will either be set as READWRITE or READONLY. READWRITE grants full access to the point; it can be browsed and written to. The READONLY status is used to block writes to a point that is allowlisted. Any time a client tries to access an unlisted point, or write to one that is listed as READONLY, the action will be prevented and an error message will be sent to the OPC Server log.