Blocks (PID-STC) to control interacting loops whose interaction can be eliminated, by using an example of temperature control in a distillation column:
TC 1 TC 2 PID controller TC 1 TC 2 m2 m1 T1 T2 LL - 1 LL - 2 g21 g22 g12 g11 + + Distillation column - -
Figure 1.13.8-12 Controlling Interacting Loops whose Interaction Can Be Eliminated
If interaction exists between the column top temperature and column bottom temperature con- trol segments of a distillation column process, first execute non-interacting control.
The method of non-interacting control is shown below:
In the figure, when the transmission function between the output mi and temperature Tj of the
controller TCi is gij. T1 and T2 will be represented as follows after non-interacting elements
LL-1 and LL-2 are applied: T1 = (g11-g12 • g21/g22) m1
T2 = (g22-g12 • g21/g11) m2
As a result, the process is divided into two control loops that are regulated based on T1 and
T2, respectively.
Configure STC after confirming the result of this non-interacting control.
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Controlling a Loop Subject to Impulse Noise
When a Self-Tuning PID Controller Block (PID-STC) is used to control a loop subject to im- pulse noise, the Self-Tuning PID Controller Block (PID-STC) estimates process characteris- tics after removing the impulse noise. When noise generates frequently, set a noise band (NB).
If impulse noise is generated frequently at intervals of TR/10 or shorter, consider using filters to remove the noise.
1.14
Manual Loader Block (MLD)
Manual Loader Block (MLD) may be applied to output manipulated output value (MV) to man- ually operate final control elements, such as control valves.
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Manual Loader Block (MLD)
▼ Connection
Manual Loader Block (MLD) outputs manipulated output value (MV) set from operation and monitoring function. When in tracking (TRK) mode, the tracking input signal received from the TIN terminal is output as manipulated output value (MV).
The figure below shows a function block diagram of the Manual Loader Block (MLD): TSI TIN OUT (TSW) (MV, ∆MV) SUB MV Output processing
Figure 1.14-1 Function Block Diagram of Manual Loader Block (MLD)
The table below shows the connection methods and connected destinations of the I/O termi- nals of the Manual Loader Block (MLD):
Table 1.14-1 Connection Methods and Connected destinations of the I/O Terminals of Manual Loader Block (MLD)
I/O terminal
Connection method(*1) Connection destination(*1)
Data refer-
ence Data set-ting connection Process I/OTerminal SoftwareI/O Functionblock
OUT Manipu-lated output x x x x SUB Auxiliaryoutput x Δ x x TIN Trackingsignal input x Δ x x TSI TrackingSW input x Δ x x x *1: x: Connection allowed
Blank: Connection not allowed
Δ: Connection allowed only when connecting to a switch block (SW-33, SW-91) or inter-station data link block (ADL).
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Function of Manual Loader Block (MLD)
The MLD block performs output processing and alarm processing.
The only processing timing available for the MLD block is a periodic startup. Selections avail- able for the scan period used to execute a periodic startup include the basic scan period, the medium-speed scan period (*1), and the high-speed scan period.
SEE
ALSO For more information about the types of output processing and alarm processing possible for the MLD block,
refer to:
1.1.3, “Input Processing, Output Processing, and Alarm Processing Possible for Each Regulatory Con- trol Block” on page 1-12
For more information about the output processing, refer to:
4, “Output Processing” in the Function Blocks Overview (IM 33K03E21-50E) For more information about the alarm processing, refer to:
5, “Alarm Processing-FCS” in the Function Blocks Overview (IM 33K03E21-50E)
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Data Items - MLD
Table 1.14-2 Data Items of Manual Loader Block (MLD)
Data Item Data Name Entry Permittedor Not (*1) Range (*2) Default (*2)
MODE Block mode x --- O/S (MAN)
ALRM Alarm status --- NR
AFLS Alarm flashing status --- 0 AF Alarm detection specifica-tion --- 0 AOFS Alarm masking specifica-tion --- 0 MV Manipulated output value Δ (*3) MV engineering unit value MSL MH Manipulated variable high-limit setpoint x MSL to MSH MSH ML Manipulated variable low-limit setpoint x MSL to MSH MSL TSW Tracking switch x 0, 1 0 RSW Pulse width reset switch x 0, 1 0 OPHI Output high-limit index x MSL to MSH MSH OPLO Output low-limit index x MSL to MSH MSL OPMK Operation mark x 0 to 64 0 UAID User application ID x --- 0 *1: x: Entry is permitted unconditionally
Blank: Entry is not permitted Δ: Entry is permitted conditionally *2: MSH: MV scale high limit
MSL: MV scale low limit
*3: Entry is permitted when the block mode is MAN SEE
ALSO For more information about valid block modes of the MLD block, refer to:
1.15
Manual Loader Block with Input Indicator
(MLD-PVI)
Manual Loader Block with Input Indicator (MLD-PVI) may output manipulated output value while displaying the process variable (PV). It may be applied to manually operate final control elements and observing the process variable (PV) at the same time.
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Manual Loader Block with Input Indicator (MLD-PVI)
▼ Connection
Manual Loader Block with Input Indicator (MLD-PVI) displays the value input from the IN ter- minal as process variable (PV). It also outputs the value set from operation and monitoring function as manipulated output value (MV). In tracking (TRK) mode, the block outputs the tracking input signal received from the TIN terminal as manipulated output value (MV). The figure below shows a function block diagram of the Manual Loader Block with Input Indi- cator (MLD-PVI): MV PV TSI OUT (TSW) (PV, ∆PV, MV, ∆MV) TIN Output processing SUB IN processingInput
Figure 1.15-1 Function Block Diagram of Manual Loader Block with Input Indicator (MLD-PVI) The table below shows the connection methods and connected destinations of the I/O termi- nals of the Manual Loader Block with Input Indicator (MLD-PVI):
Table 1.15-1 Connection Methods and Connected destinations of the I/O Terminals of Manual Loader Block with Input Indicator (MLD-PVI)
I/O terminal
Connection method(*1) Connection destination(*1)
Data refer-
ence Data set-ting connection Process I/OTerminal SoftwareI/O Functionblock
IN Measure-ment input x Δ x x OUT Manipu-lated output x x x x SUB Auxiliaryoutput x Δ x x TIN Trackingsignal input x Δ x x TSI TrackingSW input x Δ x x x *1: x: Connection allowed
Blank: Connection not allowed