ProSoft Technology MVI69-101S - Manual (Page 99)

Reference MVI69-101S ♦ CompactLogix or MicroLogix Platform
IEC 60870-5-101 Slave Communication Module
ProSoft Technology, Inc. Page 99 of 149
March 16, 2009
The Cyclic Set IV Time parameter must be set to determine how frequently the IV
Checks will be performed. If the IV bit is ON for a number of times given by the IV
Fail Count parameter the module will consider the point as invalid. The following
illustration shows how these parameters are implemented:
If the IV bit field is absent or set to 0, the invalid quality state for the point will
always be reported as valid.
If a database bit address (1 to 64000) is present, the application may consider
the point with an invalid flag if the previous logic checks the iv bit as 1 during
consecutive IV Check Delay scans. The iv bits would have to be reset to 0 to set
the point to valid state.
The IV DB bit defined for each point can be unique or many points may share the
same bit. The last case could be used when the points on an I/O module are to
be considered as one set. In this case only a single bit is required. For a point
that is the result of a computation, the valid quality state could be set for each
point individually.