SECTION 5 Examples of Function Block Combinations

Transcription

1 SECTION 5 Examples of Function Block Combinations 5-1 BASIC EXAMPLES OF CONTROL Simple Control Multi-channel Control Control for Switching Multiple Set Points Control for Switching Constants by Three Set Point Zones Ramp Program Control Time-proportional Control Monitoring and Accumulating Flowrate EXAMPLES OF APPLIED CONTROL TYPES Cascade Control Feedforward Control Sample PI Control Dead Time Compensation

2 5-1 Basic Examples of Control This section shows basic examples of how to connect the function blocks when performing control Simple Control Function block used: Basic () Use the Field I/O blocks (AI 4-point/AO 4-point blocks, etc.) as the analog input/outputs. AI 4-point Block Model 586 AO 4-point Block Model 587 Basic Note When the square root function is used in flowrate control, insert the Square Root block (Block Model 131) in analog input. Analog Output AI 4-point Block Model 586 AO 4-point Block Model 587 Square Root Block Model 131 ÁÂ Basic 152

3 5-1-2 Multi-channel Control Function blocks used: Basic () Constant ITEM Setting (Block Model 171) Step Ladder Program (Block Model 301) Use the Field I/O blocks (AI 8-point/AO 8-point blocks, etc.) as the analog input/outputs. Local Set Point value Local Set Point value Local Set Point value Constant ITEM Setting Block Model 171 Differential contact Step Ladder Program Block Model 301 AI 8-point Block Model 551 LSP Basic AO 8-point Block Model 552 Basic 153

4 5-1-3 Control for Switching Multiple Set Points Function blocks used: Basic () Contact Selector (Block Model 165) DI from CPU Unit (Block Model 451) Register multiple Set Points for switching in advance to the Constant Selector block. Connect the DI from CPU Unit block to the Constant Selector block, and switch the Local Set Points of the Basic block according to the I/O memory (contacts) of the CPU Unit. Use the Field I/O blocks (AI 4-point/AO 4-point blocks, etc.) as the analog input/outputs. Set Point switching CPU Unit I/O s memory Contact switching Contact Distributor Block Model 201 DI from CPU Unit Block Model 451 Contact Selector Block Model 165 AI 4-point Block Model 586 AO 4-point Block Model 587 LSP Basic 154

5 5-1-4 Control for Switching Constants by Three Set Point Zones Function blocks used: Basic () ITEM Setting (Block Model 171) High/Low Alarm (Block Model 111) Step Ladder Program (Block Model 301) Register three sets of constants for switching in advance to the three Constant ITEM Setting blocks. Input the current Set Point value of the Basic block to the High/Low Alarm block. Three Set Point zones can be prepared in the Step Ladder Program block by combining the high alarms and low alarms of the High/Low Alarm block. Select the Constant ITEM Setting block according to the Set Point zone. Switching according to Set Point zone Low limit alarm High limit alarm SP Constant ITEM Setting Block Number 171 Constant ITEM Setting Block Number 171 Constant ITEM Setting Block Number 171 Step Ladder Program Block Model 301 High limit Low limit High/Low Alarm Block Model 111 AI 4-point Block Number 586 P,I,D Basic SP AO 4-point Block Number

6 Block address ITEM No. Data Explanation AI 4-point block 021 Y1 (analog input 1) AO 4-point terminal block X1 (analog output 1) source designation 031 X1 (analog output 1) Basic Block source designation 029 Current SP 054 P (proportional band) 055 I (integral time) 056 D (derivative time) High/low limit alarm block X1 input value source designation 012 U1 high limit alarm 013 U2 low limit alarm Step Ladder Program block 2100 STEP00 declaration When ITEM013 low alarm of LOAD address Set constant ITEM of OUT address 101. (batch send command) When not ITEM012 (high alarm) of LOAD NOT address When not ITEM013 (low alarm) of AND NOT address Set constant ITEM of OUT address 102. (batch send command) When ITEM012 high alarm of LOAD address Set constant ITEM of OUT address 103. (batch send command) Constant ITEM Setting block 021 Setting of P (proportional band) 1 value 022 Setting of I (integral time) 1 value 023 Setting of D (derivative time) 1 value Destination designation of ITEM Destination designation of ITEM Destination designation of ITEM Batch send switch Constant ITEM Setting block 021 Setting of P (proportional band) 2 value 022 Setting of I (integral time) 2 value 023 Setting of D (derivative time) 2 value Destination designation of ITEM Destination designation of ITEM Destination designation of ITEM Batch send switch Constant ITEM setting block 021 Setting of P (proportional band) 3 value 022 Setting of I (integral time) 3 value 023 Setting of D (derivative time) 3 value Destination designation of ITEM Destination designation of ITEM Destination designation of ITEM Batch send switch 156

7 Low limit alarm ( DU) Constant selector 1 Constant selector 1 at low limit alarm ON High limit alarm Low limit alarm ( DU) Constant selector 2 Constant selector 2 at high limit alarm OFF and low limit alarm OFF ( DU) High limit alarm Constant selector 3 Constant selector 3 at high limit alarm ON 157

8 5-1-5 Ramp Program Control Follow the procedure below to perform program control for changing the Set Point value in a ramp manner proportionately to the elapsed time. Function blocks used: Basic () Ramp Program (Block Model 155) Step Ladder Program (Block Model 301) Register the ramp program (max. seven steps, each step comprising a ramp rate and soak value) in advance to the Step Ladder Program block. The Step Ladder Program is used in combination with the run/stop command from the Step Ladder Program block and the arrival at final signal to the Step Ladder Program block. Ramp program RSP SP Time Operation instruction Ramp Program Block Model 155 Step Ladder Program Block Model 301 Arrival at final st200 AI 4-point Block Model 586 RSP Basic AO 4-point Block Model

9 5-1-6 Time-proportional Control Follow the procedure below to perform time-proportional control where contact output (ON/OFF) changes proportionately to the ON/OFF time ratio. Function blocks used: Basic () Analog/Pulse Width Converter (Block Model 192) Assign the of the function block to the Analog/Pulse Width Converter block. The Analog/Pulse Width Converter block outputs the ON/OFF pulse signal obtained by changing the ON and OFF times proportionally to. Analog/Pulse Width Converter SSR Time-proportional output Contact output AI 4-point Block Model 586 DO 16-point Block Model 514 Contact Distributor Block Model 201 Timeproportional Analog/Pulse Width Converter Block Model 192 Basic Block Model

10 5-1-7 Monitoring and Accumulating Flowrate Function blocks used: PI 4-point (Block Model 562) Accumulator for instantaneous value input (Block Model 150) Connect the instantaneous value output value of the PI 4-point block to the Accumulator for instantaneous value input block when accumulating 8-digit accumulated values based on the instantaneous values from the Pulse Input Unit CS1W-PPS01. Example Let s apply scaling of 0 to 6000 to zero (0%) through to span (100%) of the pulsse input instantaneous value, and set accumulation to maximum per hour. (The accumulated value is taken to be when 6000 has continued for 100% for one hour.) The accumulation result is stored to ITEM012 and ITEM013 of the Accumulator for instantaneous value input block. Pulse input PI 4-point Block Model 562 Instantaneous value Accumulator for instantaneous value input Block Model 150 Block address ITEM No. Data Explanation PI 4-point terminal block Instantaneous value output range 3: 0 to to Y1 (instantaneous value output value 1) Note % Accumulator for instantaneous value input X1 source designation 008 Input QR accumulation rate (accumulation value when input 100% is continuous for one hour) TU time unit (2: time) to 9999 Accumulated value (lower 4 digits) to 9999 Accumulated value (upper 4 digits) Note 1 This instantaneous value differs from the instantaneous value, that is reflected in the allocated relay words n+1 to n+4 of the Pulse Input Unit CS1W-PPS01, in that the instantaneous value is for each operation cycle of the PI 4-point block. 160