ProSoft Technology MVI56-104S - Manual (Page 139)

Reference MVI56-104S ♦ ControlLogix Platform
User Manual IEC 60870-5-104 Server Communication Module
ProSoft Technology, Inc.
Page 139 of 188
November 18, 2009
Invalid Bit Monitoring
This feature allows the application to set the invalid (IV) quality bit of the protocol
for all the monitored ASDU types supported. If the feature is enabled, the status
of each point configured by the user can have the individual IV quality bit
determined by the processor.
The parameters required to support this feature are:
Cyclic Set IV Time
IV Check Delay Time
IV Fail Count
To disable this feature, set the IV Fail Count parameter to 0. 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 used, the Cyclic Set IV Time parameter must be at least 3 times larger
than the IV Check Delay Time.
The C YCLIC S ET IV T IME parameter determines the interval at which the driver will
set all the IV bits for the points being monitored in the module. If the IV bit is ON
for the number of times specified by the IV
F AIL C OUNT parameter , the point is in
an invalid state. The driver will check the state of each bit at the frequency
determined by the IV
C HECK D ELAY T IME .
The values for the parameters must permit the driver to properly execute the
logic. For example, the value for C
YCLIC S ET IV T IME should be twice the IV
C HECK D ELAY T IME , multiplied by the IV F AIL C OUNT . If the cyclic timer is set to a
smaller value, the logic may not execute correctly.