7.4.2
Diagnostic Alarm Reset
There are three ways to reset a diagnostic alarm:
•
from the ToolboxST Application (as displayed in the
on the previous page of the document)
•
from the Alarm Viewer (right-click the alarm and select
Reset
) — refer to GEI-100620
•
using a SYS_OUTPUTS block and the RSTDIAG input pin — refer to GEI-100682
Note
Application engineers often program a CIMPLICITY push button to allow for a diagnostic reset using the RSTDIAG
input pin.
7.4.3
Time Stamping
The time stamp applied to an I/O pack diagnostic alarm is the time when that diagnostic originated. When a diagnostic has
been reset, a subsequent occurrence of the same diagnostic then creates a new time stamp. If a diagnostic alarm occurs several
times without being reset by the operator, it retains the original time stamp.
The WorkstationST
*
Alarm Viewer Live View displays the diagnostic time when each transition to the active state occurs. If a
diagnostic alarm occurs several times, a new time stamp is applied by the WorkstationST Alarm Server for display in the
WorkstationST Alarm Viewer. However, if the Alarm Server is restarted, or if the connection to the I/O pack's owning
controller is lost, then the Alarm Server must get an updated dump of the current state of all I/O pack diagnostics from the
controller. Since the I/O pack only retains the original time when the diagnostic first occurred, the Alarm Server and Alarm
Viewer would then show the original time after the restart and reconnect. Refer to GEI-100620, WorkstationST Alarm Viewer.
The ToolboxST application has an I/O Diagnostic Viewer for displaying the I/O pack's current diagnostics alarm status. It
displays the I/O pack's known time stamp, which is the time of the first occurrence of the diagnostic. Each time the user
refreshes the viewer, the pack's time stamp is obtained. Refer to GEH-6700, ToolboxST User Guide for Mark VIe Control, the
section, I/O Diagnostic Viewer.
7.4.4
Voter Disagreement Diagnostics Detection (VDDD)
Each I/O pack produces diagnostic alarms when it is configured as TMR and any of its inputs disagree with the voted value of
that input by more than a configured amount. This feature allows the user to find and fix potential problems that would
otherwise be masked by the redundancy of the control system. The user can view these diagnostics the same way one views
other diagnostic alarms. The designated controller triggers these diagnostic alarms when an individual input disagrees with
the voted value for a number of consecutive frames. The diagnostic clears when the disagreement clears for a number of
frames.
The user configures voter disagreement diagnostics for each variable. Boolean variables are all enabled or disabled by setting
the DiagVoteEnab signal to enable under the configuration section for each input. Analog variables are configured using the
TMR_DiffLimit setting under configuration for each point. This difference limit is defined in one of two ways. It is
implemented as a fixed engineering units (EU) value for certain inputs and as a percent of configured span for other variables.
For example, if a point is configured as a 4-20 mA input scaled as 0-40 EU, its TMR_DiffLimit is defined as a percent of
(40-0). The type of limit checking used is spelled out in the dialog box for the TMR_DiffLimit for each board type. The
following table provides some examples of TMR limit checking.
170
GEH-6721_Vol_I_BP
GEH-6721_Vol_I Mark VIe and Mark VIeS Control Systems Volume I
Public Information
