Process Control Systems Episode 6 pot

... prime variable. Secondary Controller Primary controller FIG 6. 1. Cascade control resolves the process into two parts, each within a closed loop. 1 56 1 Multiple-loop Systems The vector gain of ... constant gain for the primary loop. RATIO CONTROL SYSTEMS In a ratio control system, the true controlled variable is the ratio K of two measured variables X and Y: K=; (6. 3) Contro...

Ngày tải lên: 12/08/2014, 16:21

... 14.7 12.2 359 14.5 12.1 394 13.9 11.4 361 14.1 11 .6 395 14.2 11 .6 366 14.2 12.0 3 96 14.0 11 .6 367 13.9 11 .6 397 14.0 11.1 368 14.5 11.5 398 14.0 11.4 369 13.8 11.1 399 14.7 11.4 370 13.9 11.5 ... 0. 16 0.73 0.183 0.08 A 11 0.13 0 .67 0. 168 0.10 B 12 0.17 0 .69 0.173 0.10 C 13 0.18 0 .64 0. 160 0.05 D 14 0.17 0 .65 0. 163 0.05 A 15 0.22 0.74 0.185 0.05 B 16 0.15 0.72 0.180 0.0...

Ngày tải lên: 11/08/2014, 20:22

... between the controllabilit’y of this process and the two-capacity process. Taken on the basis of an equal ratio of secondary to primary element, the dead-time plus capacit’y process is 400/al6 or ... 1.25. Zntegral control of dead time (aboue) is the same as propor- tional control of a dead-time plus integrating process (below). Dynamic Elements in the Control Loop I P7 Proport...

Ngày tải lên: 12/08/2014, 16:21

... 0 125 - 36 P 127r&, 158 220 361 llOTd/T, 127 1 96 22%,/T, 254 540 Process 70 Gain 4.OOsd 0 .64 rd/r, 4.80 0. 76 6.00 0.95 8.00 1.27 -__ 3.197d 0.517&1 4.00 0 .64 5.37 0. 86 2. 867 d 0.45rJn 4.00 0 .64 6. 79 1.08 Perform- ance, PR/100 m 4 .52sd2/rl 3 .65 4.58 0.9772/71 0.81 0. 96 2. ... Three-mode Controllers Modes Proportional plus reset Noninter- 0.51Td acting 0 .64...

Ngày tải lên: 12/08/2014, 16:21

... Journal, November, 1 963 . 3. Shinskey, F. G.: Analog Computing Control for On-line Applications, Control Eng., November, 1 962 . 4. Mathias, R. A., and R. I. Van Nice: Adaptive Control Systems- A Survey, Electra-Technology, ... October, 1 960 . 5. White, B.: The Quarie Optimal Controller, Instruments and Automation, Novem- ber, 19 56. 6. Bernard, J. W., and F. J. Soderquist: Dow Eva...

Ngày tải lên: 12/08/2014, 16:21

... Feedforward Analog Computer Control of a Superfractionator, Control Eng., March, 1 964 . 4. Shinskey, F. G.: Analog Computing Control for On-line Applications, Conlrol Eng., November, 1 962 . PROBLEMS 8.1 ... Manipulated variable - c * Process Controlled variable * I I FIG 8.1. The control system embodies a for- ward flow of information. Feedforward Control I 223 MzY FIG 8.17. T...

Ngày tải lên: 12/08/2014, 16:21

... The control system for once-through boiler must be as closely knit as the process itself. Control of Energy Transfer h P a Set boint to combustion- :ontrol system Set point to feedwater flow controller match ... heating medium, manipulation of its flow t’o bring about temperature control of the process fluid is effective. If the process fluid is boiling, steam flow directly inf...

Ngày tải lên: 12/08/2014, 16:21

... cascade control. 6. P RP = 1.75 set; 70 = 5.0 sec. 6. 3 Two level controllers must be used, one set for high level, the other low. The outputs of the flow controller and the high-level controller ... d = 1 .6 F, peak to peak. 5.3 T,, = 75 set; 14 = 3.O”F, peak to peak. 5.4 2 = 3.8%; 7, = 3.8 sec. 5.5 Preload 9 = 30%; td = 3 .6 min; et = 4.45”F. 5 .6 P = 18%. Chapter...

Ngày tải lên: 12/08/2014, 16:21

... ratio -control systems, 163 , 164 Raoult’s law 3 26 Ratio contral, 160 - 167 dividers in, 160 of flow, 161 - 167 of fuel and air, 242, 243 Ratio control, infinite rangeability, 163 , 164 multipliers in, 162 - 164 Ratio ... derivative, 31, 95, 96 of reset, 96- 99 Second-integral control, 166 , 167 Secondary loop, 154-1 56 (See also Cascade control) Selective control systems...

Ngày tải lên: 12/08/2014, 16:21