Chemtrac HydroAct HA4, Руководство пользователя

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70 Chapter 4. Controls
Enabled Enables the boost feature and allows users to initiate the boost from the “Boost Status”
option.
Action Options are “Output” or “Setpoint”. Selecting “Output” allows the user to set a pre-determined
control output. Selecting “Setpoint” allows the user to set a new target for the PID control.
Value Set the new output value or target setpoint, based on the selection above.
Duration Set the duration of the boost. Value is in HH:MM:SS format, up to 24 hours.
Delay
Set the inhibition delay, the time after a boost before a user can initiate a subsequent boost.
Value is in HH:MM:SS format, up to 24 hours.
4.1.2.4.6 Options Tab
Fail-safe on PV Alarm. If the process variable goes into data alarm the controller will go into fail-safe
mode.
4.1.2.5 Alarms and Thresholds
Alarms are the means by which values obtained from sensors cause visible, audible or physical action
to occur. Alarms are not to be confused with relays
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, as very flexible firmware and electronics are
utilized. An alarm in a HydroAct 4 unit will be visible on the screen and sound a buzzer. Two output
alarms per control output are available. Thresholds are similar to alarms except that they are events
that are supposed to occur and therefore will not cause the instrument to go into “Alarm”. Thresholds
are used to trigger relays to cause something to happen when a control output reaches a value.
To access the configuration:
Options → Alarms & Thresholds
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A mechanical or electronic device mounted on the electronics within the instrument that can switch (much like a light switch).
The number and type of relays is specified at the time of order.