PERFORMING A CONTROL OPERATION WHICH DOES
NOT IN FACT OCCUR.
When the tag is put into the control inhibit
mode, writing to the Field element value is prohibited. If the
system is configured in such a way that it does not give the
operator any indication that the tag is in the control inhibit
mode, the operator may assume that he is performing a control
operation which does not, in fact, occur.
Configure the system in such a way that it
provides a visual indication to the operator that a tag is in the
control inhibit mode.
Failure to follow these instructions can
result in death, serious injury, or equipment damage.
To provide a visual indication to the operator
that a tag is in the control inhibit mode the following can be
done:
Set any of the following Citect.ini parameters in
such a way that control inhibit mode will be indicated by changing
the background color or overlaying the numeric or text graphics
objects and symbol set objects with a dithered pattern:
[Page]ControlInhibitDitheringColor
[Page]ControlInhibitDitheringDensity
[Page]ControlInhibitTextBackgroundColor
and set [Page]IgnoreValueQuality parameter to a
value of 0 or 2.
or
Use the Control Mode element value (0 if the tag
is not in the control inhibit mode or 1 otherwise)
or
Use the Field element quality Tag Status
ControlInhibit bit (1 if the tag is in the control inhibit mode or
0 otherwise)
Control Mode
Control inhibit mode allows you to prohibit
writing to the Field tag element. Setting a tag in Control inhibit
mode is applied system wide. Writing to the Field element will be
prohibited for each of the I/O Data Consumers.
Control inhibit mode is controlled by the “Control
Mode” element which is described in the following table.
Reference
Syntax
CitectSCADAData type
Description
TagName.ControlMode
INT
Value of Control
Mode element
TagName.ControlMode.V
INT
Value
Allowed values are:
0 – Control inhibit mode is Off.
1 – Control inhibit mode is On.
Default value: 0.
TagName.ControlMode.VT
TIMESTAMP
Timestamp of
when the value last changed
TagName.ControlMode.Q
QUALITY
Quality. The
Control Mode quality is QUAL_GOOD if the tag was put into the
Control inhibit mode on the primary server and it was propagated to
redundant servers. Otherwise the general quality status will be
QUAL_UNCR and the extended susbstatus will be QE_NOT_REPLICATED to
indicate that not every redundant server is aware of the fact that
the tag is in Control inhibit mode.
TagName.ControlMode.QT
TIMESTAMP
Timestamp of
when the quality last changed
TagName.ControlMode.T
TIMESTAMP
Time of when the
tag was put in or out of the Control inhibit mode. (equal to 0 at
start up)
Note: The quality of tags referenced by
items, ex. Tag1.v or Tag1.Field.t, is GOOD and its timestamps are 0
(INVALID TIMESTAMP). Therefore they give no visual indication of
any not good quality, error or change in handling state such as
control inhibit or override mode regardless of the setting used for
the [Page] IgnoreValueQuality parameter.
