▼ PID Control Algorithm
For control computation, the PID-TP block holds the same control algorithms as a PID control- ler block. The algorithms are:
• PV proportional and derivative type PID control (I-PD) • PV derivative type PID control (PI-D)
• Basic type PID control (PID) • Automatic determination type 2 • Automatic determination type
The control algorithm can be specified on the Function Block Detail Builder: Choose one from the followings.
• PV proportional and derivative type PID control (I-PD) • PV derivative type PID control (PI-D)
• Basic type PID control (PID) • Automatic determination type 2 • Automatic determination type
The default is "PV proportional and derivative type PID control (I-PD)."
When the block mode of the PID Controller Block is remote cascade (RCAS), the PID control algorithm [Automatic determination] and [Automatic determination 2] will act as follows:
• Automatic determination type: Same actions as in the cascade (CAS) mode. • Automatic determination type 2: Same actions as in the automatic (AUT) mode.
SEE
ALSO For more information about PV proportional and derivative type PID control (I-PD) algorithm, refer to:
“n PV Proportional and Derivative Type PID Control (I-PD)” on page 1-94
For more information about the control algorithms other than PV proportional and derivative type PID control (I-PD), refer to:
“n PID Control Computation” on page 1-51
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Time-Proportioning ON/OFF Output
▼ Time-Proportioning ON/OFF Period
The PID-TP block performs time-proportioning ON/OFF output as output signal conversion. In the time-proportioning ON/OFF output, a contact output (1 point) defined to the OUT termi- nal is turned ON for the period of time proportioning to the manipulated output value (MV) within the ON/OFF period.
Time OFF
ON
Proportional to manipulated output value (MV)
ON/OFF period (constant)
On time (sec.) = ON/OFF period (sec.) • Output value (MV value) (%) 100 (%)
Figure 1.10-2 Operation of Time-Proportioning ON/OFF Output
The time-proportioning ON/OFF output is always off against 0 % and on against 100 % of the manipulated output value (MV) respectively. For instance, if the ON/OFF period is 10 seconds and manipulated output value (MV) is 80 %, the ON time will be 8 seconds.
The time-proportioning ON/OFF period is set through the Function Block Detail Builder. Time-proportioning ON/OFF Period: 1.00 to 256.00 seconds
Default is 1.00 second.
If there are multiple PID-TP blocks, their simultaneous turning on at the beginning of the ON/OFF period will cause a large fluctuation in the load of power supply for the final control element (such as heaters). To reduce such load fluctuation, the phases of PID-TP blocks’ ON/OFF outputs are automatically shifted.
• Phasing the ON/OFF period of the function blocks. The phasing is performed according to the internal block numbers so as to prevent the multiple blocks ON/OFF in the same phase (*1).
• Phasing the ON/OFF period of the I/O modules. For the “time-proportioning ON/OFF pulse period” in the Details Setting dialogue box of IOM Builder, set the same value as the “time-proportioning ON/OFF period” specified with Function Block Detail Builder. In addition, specify “Operation start offset” in the Details Setting dialogue box of IOM Build- er so as to prevent a heavy load caused by multiple outputs ON/OFF in the same period (*2).
*1: The function is supported in SFCS and PFCS
*2: The function is supported in FFCS series, KFCS2, KFCS, LFCS2, and LFCS
IMPORTANT
After FCS initial start, the PID-TP MV will be forced to 0 (MSL). The MV saved by [Save tun- ing parameter] command will be ignored.
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Data Items - PID-TP
Table 1.10-3 Data Items of Time-Proportioning ON/OFF Controller Block (PID-TP) (1/2)
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 PV Process variable Δ (*3) PV engineering unit value SL RAW Raw input data Value in the unit at the con-nection destination --- SUM Totalizer value x Engineering unit value 0 SV Setpoint value Δ (*4) Value in the same engi-neering unit as PV SL CSV Cascade setpoint value x Value in the same engi-neering unit as PV SL RSV Remote setpoint value Δ (*5) Value in the same engi-neering unit as PV SL DV Control deviation value Value in the same engi-neering unit as PV 0 VN Input compensation value x --- 0 MV Manipulated output value Δ (*6) 0 to 100 % 0 % RMV Remote manipulated outputvalue Δ (*7) 0 to 100 % 0 %
Data Item Data Name Entry Permittedor Not (*1) Range (*2) Default (*2)
RLV1 Reset limit value1 0 to 100 % 0 % RLV2 Reset limit value 2 0 to 100 % 0 % HH High - high limit alarm set-point x SL to SH SH LL Low - low limit alarm set-point x SL to SH SL PH High - limit alarm setpoint x SL to SH SH PL Low - limit alarm setpoint x SL to SH SL VL Velocity alarm setpoint x ± (SH - SL) SH - SL PVP Velocity-Reference Sample Value in the same engi-neering unit as PV --- DL Deviation alarm setpoint x ± (SH - SL) SH - SL *1: x: Entry is permitted unconditionally
Blank: Entry is not permitted Δ: Entry is permitted conditionally *2: SH: PV scale high limit
SL: PV scale low limit
*3: Entry is permitted when the data status is CAL *4: Entry is permitted when the data mode is CAS or RCAS *5: Entry is permitted when the block mode is RCAS *6: Entry is permitted when the block mode is MAN *7: Entry is permitted when the block mode is ROUT
Table 1.10-4 Data Items of Time-Proportioning ON/OFF Controller Block (PID-TP) (2/2)
Data Item Data Name Entry Permittedor Not (*1) Range Default
MH Manipulated variable high-limit setpoint x 0 to 100 % 100 % ML Manipulated variable low-limit setpoint x 0 to 100 % 0 % SVH Setpoint high limit x SL to SH SH SVL Setpoint low limit x SL to SH SL P Proportional band x 1 to 1000 % 100 % I Integral time x 0.1 to 10,000 seconds 20 seconds D Derivative time x 0 to 10,000 seconds 0 second GW Gap width x 0 to (SH - SL) 0.0 DB Deadband x 0 to (SH - SL) 0.0 CK Compensation gain x -10.000 to 10.000 1.000 CB Compensation bias x --- 0.000 PMV Preset manipulated outputvalue x 0 to 100 % 0 %
CSW Control switch x 0, 1 0
PSW Preset MV switch x 0, 1, 2, 3 0
BSW Backup switch x 0, 1 0
OPHI Output high-limit index x 0 to 100 % 100 % OPLO Output low-limit index x 0 to 100 % 0 % OPMK Operation mark x 0 to 64 0 UAID User application ID x --- 0
Data Item Data Name Entry Permittedor Not (*1) Range Default
SH PV scale high limit Value in the same engi-neering unit as PV --- SL PV scale low limit Value in the same engi-neering unit as PV --- *1: x: Entry is permitted unconditionally
Blank: Entry is not permitted SEE
ALSO For more information about valid block modes of the PID-TP block, refer to:
1.11
PD Controller Block with Manual Reset
(PD-MR)
PD Controller Block with Manual Reset (PD-MR) performs proportional-derivative (PD) control function. This block may be applied to programmed temperature control process.
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PD Controller Block with Manual Reset (PD-MR)
▼ Connection
The PD Controller Block with Manual Reset (PD-MR) performs proportional (P) and derivative (D) control, while the integral (I) may be manually set to be applied to the control function. In programmed temperature control process, operating conditions do not remain the same throughout the process time. For example, a chemical process is accompanied by momentary generations of intense heat. In this case, among all PID actions of the controller block the in- tegral (I) actions may be weakened for a specific period of time during operation so that con- trol is performed only by proportional and derivative (PD) actions. In this type of process, it is necessary to set a wide proportional band, as a long dead time or large process time constant tends to cause hunting if an integral (I) action is performed.
By performing only proportional-derivative (PD) actions, the proportional band (P) can be nar- rowed. In addition, overshooting can be inhibited by shift the control phase by derivative (D) actions to achieve the better control result.
The figure below shows the function block diagram of PD Controller Block with Manual Reset (PD-MR): RMV SV CAS/AUT MAN INT TSI TIN BIN IN OUT (TSW) (VN) (PV, ∆PV, MV, ∆MV) SUB RSV CSV CAS AUT MAN RCAS SET MV PV computationControl processing Output processing Input processing ROUT
Figure 1.11-1 Function Block Diagram of PD Controller Block with Manual Reset (PD-MR)
The table below shows the connection methods and connected destinations of the I/O termi- nals of the PD Controller Block with Manual Reset (PD-MR):
Table 1.11-1 Connection Methods and Connected destinations of the I/O Terminals of PD Controller Block with Manual Reset (PD-MR)
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
SET Setting in-put x x
I/O terminal
Connection method(*1) Connection destination(*1)
Data refer-
ence Data set-ting connection Process I/OTerminal SoftwareI/O Functionblock
SUB Auxiliaryoutput x Δ x x
BIN Compensa-tion input x Δ x x TIN Trackingsignal input x Δ x x TSI TrackingSW input x Δ x x x INT InterlockSW 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 PD Controller Block with Manual Reset (PD-MR)
The PD-MR block performs input processing, control computation processing, output pro- cessing, and alarm processing.
The only processing timing available for the PD-MR block is a periodic startup. Selections available for the scan period used to execute a periodic startup include the basic scan peri- od, the medium-speed scan period (*1), and the high-speed scan period.
*1: The medium-speed scan period can only be used for the FFCS series, KFCS2, KFCS, LFCS2, and LFCS. SEE
ALSO For more information about the types of input processing, output processing, and alarm processing possible
for the PD-MR 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 input processing, refer to:
3, “Input Processing” in the Function Blocks Overview (IM 33K03E21-50E) 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)