Future Design MCTB 4.3, Руководство пользователя

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MCTB
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4.5 Soft Alarm Configuration
The Soft Alarm Configuration screen is accessed from the Setup menu. The screen allows the user or OEM to
program each soft alarm up to the total number entered on the Control Setup screen. When more than one
soft alarm is programmed, the left/right scroll buttons will be provided at the top right of the screen in order to
view/edit settings for each alarm.
The
Alarm Source drop down menu selection lists all loops, limits, monitor points and math equations (if
configured) to be chosen for the process value to be monitored by the alarm. Any configured logic equations
are also included as alarm source selections in which the true/false state of the equation is utilized to activate
the alarm.
The
Alarm Type drop down menu selection is used to choose the type of alarm. Alarm choices include process
(active) high, process (active) low, deviation high, deviation low, deviation band and end of program. The
deviation alarms can only be chosen for control loops. For the limit, monitor points, math/logic equations and
loops programmed for monitor only, there is no set point to associate with the alarm.
For the following alarm descriptions, PV = process value, SV = the control set point value, ASP is the alarm set
point and AHY is the alarm hysteresis.
Process (Active) High The alarm is independent of set point. When the process value is higher than the alarm
set point (PV > ASP), a process high alarm occurs. When the process value is lower
than the alarm set point minus the alarm hysteresis (PV < ASP
–AHY), the alarm is off.
When the alarm source is a logic equation, the alarm will activate when the result of the
logic equation is true. The alarm will deactivate when the result of the logic equation is
false.
Process (Active) Low The alarm is independent of set point. When the process value is lower than the alarm
set point (PV < ASP), a process low alarm occurs. When the process value is above the
alarm set point plus the alarm hysteresis (PV > ASP+AHY), the alarm is off.
When the alarm source is a logic equation, the alarm will activate when the result of the
logic equation is false. The alarm will deactivate when the result of the logic equation is
true.
Deviation High The alarm is dependent upon the control set point and alerts the operator when the
process value deviates too high over the set point value. For deviation high alarms, the
alarm set point is entered as a positive value. When the process is higher than the
control set point plus the alarm set point (PV > SV+ASP), a deviation high alarm occurs.