Future Design MCTB 4.3, Руководство пользователя

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MCTB
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The minimum and maximum values for the lower and upper limits are defined by the OEM
limits set in the MCTB configuration. The MCTB prevents the user from entering set point limits
outside of these configuration values. Consult your OEM or equipment installer regarding the
maximum set point limits permitted for your system.
9.3.1 Ramp Rate Limits
(MCTB 4.3” version 4MA V1.3 only)
When the loop is configured for ramp rate operation, the set point Limit screen will provide fields for the
adjustment of the set point rate of change as well as the deviation hold. These limits are used to define the
rate at which the set point increases or decreases towards the target set point, as well as when to pause the
set point ramp should the process not be able to keep up.
The Rate Down and Rate Up entries allow the user to define the rate at which the set point ramps towards the
target set point entered by the user from the current process value. When a new set point is entered, if the set
point is below the current process value, the set point will utilize the rate down. When the new set point entered
is above the current process value, the set point will ramp according to the rate up entry. The minimum and
maximum values allowed to be entered for rate down and rate up are defined for the loop in the Configuration.
This allows the user or OEM to define the minimum/maximum rate of change allowed during normal operation.
NOTE: If a rate down/up entry of 0 is made, the set point change will be made immediate. For example, if
the rate down is 0 and a new set point of 10 is entered for the loop and the current process value is
90, the set point will immediately change to 10 with no ramp rate. This allows a loop to be configured
for ramp rate operation in the configuration, but also allows the user to bypass ramp rate operation
when not required by setting the rate of change to 0.
The Deviation Hold entry is used to temporarily pause the set point ramp should the process not be able to
keep up with the rate of change in set point. When the difference between the set point and process value
exceeds the deviation hold entry, the set point will be held at its current value until the process falls back within
the band. The set point would then continue ramping according to the corresponding rate of change entry.
9.4 Cascade
The Cascade settings screen allows for the adjustment of the cascade low and high or ratio set point. It is
available on systems programmed for the Cascade or Dual Loop + Cascade control type in the Configurator.
NOTE: The implementation of cascade control and its mode of operation is application specific and
determined by the system designer. The MCTB provides process, deviation and ratio control modes.
The cascade control mode is defined by the OEM in the MCTB configuration. If there are questions
or concerns about the configuration and operation of your MCTB controller, contact your OEM for
further information. Only your OEM can address equipment related issues.