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MCT-CM
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NOTE: The set point entry is critical in order for the step to operate correctly when Edge is selected as the
wait type. During the wait state, each selected loop and/or monitor input must arrive at or cross the
wait set point in order for the program to resume operation. Thus, the previous step must ensure that
the process values will be moving towards the target wait set point prior to the wait step beginning. If
all selected loops and/or monitors do not cross the wait set point after the wait step has started, the
program will pause indefinitely on the step until the user takes action.
The digital input selections are
made by pressing ‘Digital’ button on the Wait screen. When using the digital
input wait for selection, the digital input must be configured as a
‘wait input’. If it is not configured as a ‘wait
input
’, the program will wait on the step indefinitely until the user takes action since the input is unable to trigger
the end of the wait condition. See section 10.7 Digital Inputs for information on setting the digital input function.
6.1.3.1 Delta Control Setting
The delta control setting, accessed by pressing the
“Delta” button, is a special feature of MCT that works in
conjunction with the loop and monitor wait for setting. Typical uses for this function include wood drying or
heat-treating processes (metal, food, etc.) where temperature gradients through the product need to maintained
at a minimum.
When enabled for a loop, MCT will use the lowest process value (if a wait type of Increase is selected) or the
highest process value (if wait type of Decrease is selected) of all the selected loops and/or monitor inputs
programmed for the wait condition, and apply the delta set point offset to that value. The resulting value (lowest
loop or monitor input + Delta SP or highest loop or monitor input
– Delta SP) will be used as the set point for
the loop(s) selected in the list.
To enable delta control, at least one of the available control loops must be selected to have the delta set point
applied and a wait type of Increase or Decrease must be selected. If no loops are selected or a wait type of
Edge is selected, delta control will not be applied and the step will be a normal wait step.