The following items are contained in the MPC SISO function block faceplate:
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MNPLT1 Descriptor – The configured description of the manipulated variable.
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CNTRL1 Descriptor – The configured description of the controlled variable.
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BKCAL_IN1 Variable – This area displays the BKCAL_IN1 value of the MPC SISO block in cyan. The background color of the 3-D box changes from gray to orange or red when the Output status becomes uncertain or bad, respectively. The displayed decimal format of BKCAL_IN1 is determined by the MNPLT1_SCALE.DECPT parameter field.
Clicking this box while the target mode of the block is MAN or OOS produces a dialog prompting the operator for an Output value. The valid range for input is defined by the EU 0 and EU 100 values of the MNPLT1_SCALE parameter. Valid input ranges from -10 percent to 110 percent of MNPLT1_SCALE.
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Controlled Variable – This area displays the controlled variable value of the MPC SISO block in yellow. The background color of the 3-D box changes from gray to orange or red when the PV status becomes uncertain or bad, respectively. The CNTRL1 value is visible in the decimal format provided by CNTRL1_SCALE.DECPT.
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Units – This is the engineering units description
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EU 100 – This is the value corresponding to 100% of scale
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Constraint High and Low Limits – These arrowheads are vertically positioned relative to the bar graph to indicate the High and Low Constraint Limits. Although these arrows cannot be dragged with the mouse, the values they indicate can be modified by using the detail display.
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SP1 High and Low Limits – These arrowheads are vertically positioned relative to the bar graph to indicate the High and Low SP Limits. Although these arrows cannot be dragged with the mouse, the values they indicate can be modified by using the detail display..
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AUTO/MAN buttons – These buttons are used to set the target mode of the MPC SISO block to the corresponding mode. The visibility of these three buttons is based on permitted modes of the MPC SISO block. Buttons for AUTO and MAN mode are displayed when the respective mode is a permitted mode.
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Target Mode – This field contains a word in white text that describes the target mode for the loop. The background changes to blue when the target mode and normal mode are different.
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Actual Mode – This field contains a word in yellow text that describes the ACTUAL mode of the loop. The background changes to blue when the actual mode and normal mode are different.
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Setpoint slew keys – These gray buttons with a white arrowhead pointing up or down are used to increment or decrement the setpoint value by 1 CNTRL1 engineering unit if CNTRL1_SCALE.F_DECPT is less than or equal to 1. If CNTRL1_SCALE.F_DECPT is 2 or greater, each click changes the setpoint by 0.1 engineering unit. The setpoint slew keys are visible if the target mode is AUTO, MAN, or OOS.
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Manipulated Variable Output slew keys – These gray buttons with a cyan arrowhead pointing up or down are displayed below the Setpoint Slew keys only when the loop has a target mode of MAN or OOS. Click the up arrow or down arrow to increment or decrement the MNPLT1 value by 1 MNPLT1 engineering unit.
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BKCAL_IN1 bar graph – This field indicates the value of BKCAL_IN1, which is the same as the value displayed in the BKCAL_IN1 display box.
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Manipulated Variable Output slider – This large cyan arrowhead to the left of the Output Bar Graph is displayed only when the target mode of the block is MAN or OOS. To move this button, hold down the left mouse button while the cursor is over the arrowhead and then move the mouse up or down to correspond to the new manipulated value desired. The new value is then written to the MNPLT1 parameter of the loop. The arrowhead remains in the new position.
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Manipulated Variable Limits – These cyan arrowheads are vertically positioned relative to the Manipulated Variable bar graph to indicate the High and Low Limits. Although these arrows cannot be dragged with the mouse, the values they indicate can be modified by using the block's detail display.
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Tick marks – This vertical arrangement of black lines is used to indicate percentages of CNTRL1 and MNPLT1 scale.
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CNTRL1 bar graph – This graph indicates the value of the CNTRL1 parameter for the block, which is the same as the value displayed in the Controlled Variable display box.
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Setpoint slider – To move this button, hold down the left mouse button with the cursor over the arrowhead and then move the mouse up or down to correspond to the new SP1 (setpoint) value desired. The new value is then written to the SP1 parameter of the loop. The arrowhead is controllable only when the target mode is AUTO, MAN, or OOS.
Another arrowhead with the same size and movement range as the Setpoint slider but with a transparent fill color and a black border indicates the Working Setpoint (SP_WRKn) of the nth Controlled Variable in the MPC block. This arrow's movement range is restricted within the SP Limit arrows and is the actual SP used by the controller to calculate output moves. When SPn and SP_WRKn have the same value, SP_WRKn is superimposed upon SPn and, therefore, is not distinguishable from SPn. The Working Setpoint is visible as a separate entity when setpoint ramping prevents SP_WRKn from going to SPn immediately.
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EU 0 – This area shows the value corresponding to 0% of scale.
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Detail Display button – This button is used to open the detail display for the MPC SISO block.
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Setpoint Entry - Setpoint Entry is the 3-D recessed box displaying the SP1 value of the block. The Setpoint Entry box is next to the Setpoint slider. The background color of this box changes from gray to orange or red when the CNTRL1 status becomes uncertain or bad, respectively. Clicking this box while the target mode is AUTO, MAN, or OOS produces a dialog box that prompts you for an SP (Setpoint) value. The valid range for input is defined by the engineering unit EU 0 and EU 100 values of CNTRL1_SCALE. Valid input ranges from 10 percent to 110 percent of PV scale. The SP value is then visible in the decimal format provided by CNTRL1_SCALE.DECPT.
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MPC Operate Overview button – This button is used to open the MPC Operate picture for this block.
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Limit Information - These fields display a word in yellow text representing the AV_ACT[n] value of the MPC block. The background color of these 3-D boxes change from gray to blue when the SPWRK_ACT[n] value is non-zero. The text displayed represents the following values:
Value Text
Text
0.0
Not Limited
1.0
Low Limited
2.0
High Limited
3.0
Constant