User Guide - Eurotherm Ltda

More documents

Recommendations

Info

nanodac RECORDER/CONTROLLER: USER GUIDEB2.4.5 AUTOTUNE (Cont.)AT.R2GSome load types and process conditions can cause autotune to set an incorrect value for R2G resulting in aninstability in the system after an autotune has completed, In such circumstances, the value of R2G should bechecked, and if it is low (approaching 0.1) a manual entry should be made as follows:1. In the Tune menu, set the AT.R2G parameter to ‘No’.2. In the PID menu, enter the new R2G value (calculated as described below)3. In the Tune menu, enter a value for Low Output, calculated from: Low Output = -High Output x R2G4. In the Tune menu, set ‘TuneEn’ On.R2G CALCULATION1. In the Main menu, set the controller to Manual mode2. Turn heating on (limited by the value of ‘Output High’ in the Output menu) and measure the heatingrate (‘H’ °C/minute).3. Allow the process to heat to, say, 10% above the setpoint value then turn the heating off and allow thetemperature to settle.4. Turn cooling power on (limited by the value of ‘Output Low’ in the Output menu) and measure thecooling rate (‘C’ °C/minute) whilst allowing the temperature to fall below the setpoint value.5. Calculate the value of R2G from the equation R2G = (H/C) x (Output Low/output High)Example:For a measured heating rate (H) of 10°C per min and a measured cooling rate (C) of 25° per minute and with,Output High = 80% and Output Low = 40%, then R2G = (10/25) x (40/80) = 0.4 x 0.5 = 0.2.Output HiΔCTemp---------------------- = CoolingRateΔCtimeOP PowerHeating onΔHtimeΔHTempOutput LoΔHTemp----------------------- = HeatingRateΔHtimeΔCTempΔCtimeCooling onPVSPTemperatureTimeFigure 2.4.5d R2G calculationNote: This is not a very accurate method as it does not take natural cooling into account. Its mainadvantage is that it is simple to achieve.Appendix BPage 312HA030554Issue 7 Nov 12
nanodac RECORDER/CONTROLLER: USER GUIDEB2.4.5 AUTOTUNE (Cont.)FAILURE MODESThe conditions for performing an autotune are monitored by the Tune menu parameter ‘State’. If autotuneis not successful error conditions are read by this parameter as follows:TimeoutSet if any one stage is not completed within an hour. Possible causes are the loop beingopen circuit, or not responding to the controller demands. Some heavily lagged systemsmay produce a timeout if the cooling rate is very slow.TI LimitThis is set if Autotune calculates a value for the integral term which is greater than themaximum allowable (99999 seconds). This indicates that the loop is not responding orthat the tune is taking too long.R2G Limit Error occurs if the calculate value of R2G is outside the range 0.1 to 10.0. R2G limit canoccur if the gain difference between heating and cooling is too large, or if the controlleris configured for heat/cool, but the heating and/or cooling device is turned off or notworking correctly.B2.4.6 Relative Cool Gain in Well Lagged ProcessesIn the majority of processes Relative Cool Gain R2G is calculated by the autotune algorithm as described inthe previous sections.There are occasions, however, where an alternative algorithm may be preferred. These are processes whichare heavily lagged, where the heat loss to ambient is very small so that natural cooling is extremely slow, andcertain high order plants, those that need derivative, Td. This algorithm is known as R2GPD and has beenadded to controllers from firmware version V4.10.The type of algorithm is selected using the parameter 'Tune R2G' found in the Auto-Tune list, sections 4.6.3and 4.7.3. The choices are:-StandardThis is the default as described in example 2 in section B2.4.5. and is suitable for use onmost processes. The benefit of this algorithm is that it is relatively quick. However, inthe type of process described in the previous paragraph, it can produce values whichare not ideal. These values are generally identified by R2G equal to or very close to 0.1.R2GPDIf the process is known to be heavily lagged or produces values such as those abovethen R2GPD should be selected. This algorithm extends the autotune period byputting the controller into proportional plus derivative mode (PD) and uses the outputpower demand value during this period to determine the Relative Cool Gain.OffThe automatic calculation of Relative Cool Gain can be turned off and the value enteredmanually as described in section B2.4.6.HA030554Issue 7 Nov 12Appendix BPage 313
Page 1 and 2:
nanodacUser Guidenanodac recorder/c
Page 3:
Declaration of ConformityManufactur
Page 6 and 7:
nanodac RECORDER/CONTROLLER: USER G
Page 8 and 9:
Page 10 and 11:
Page 12 and 13:
Page 14 and 15:
Page 16 and 17:
Page 18 and 19:
Page 20 and 21:
Page 22 and 23:
Page 24 and 25:
Page 26 and 27:
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41:
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 98 and 99:
Page 100 and 101:
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 138 and 139:
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 166 and 167:
Page 168 and 169:
Page 170 and 171:
Page 172 and 173:
Page 174 and 175:
Page 176 and 177:
Page 178 and 179:
Page 180 and 181:
Page 182 and 183:
Page 184 and 185:
Page 186 and 187:
Page 188 and 189:
Page 190 and 191:
Page 192 and 193:
Page 194 and 195:
Page 196 and 197:
Page 198 and 199:
Page 200 and 201:
Page 202 and 203:
Page 204 and 205:
Page 206 and 207:
Page 208 and 209:
Page 210 and 211:
Page 212 and 213:
Page 214 and 215:
Page 216 and 217:
Page 218 and 219:
Page 220 and 221:
Page 222 and 223:
Page 224 and 225:
Page 226 and 227:
Page 228 and 229:
Page 230 and 231:
Page 232 and 233:
Page 234 and 235:
Page 236 and 237:
Page 238 and 239:
Page 240 and 241:
Page 242 and 243:
Page 244 and 245:
Page 246 and 247:
Page 248 and 249:
Page 250 and 251:
Page 252 and 253:
Page 254 and 255:
Page 256 and 257:
Page 258 and 259:
Page 260 and 261:
Page 262 and 263:
Page 264 and 265:
Page 266 and 267:
Page 268 and 269:
Page 270 and 271:
Page 272 and 273:
Page 274 and 275: nanodac RECORDER/CONTROLLER: USER G
Page 348 and 349: NANODAC RECORDER/CONTROLLER: USER G
Page 374 and 375:
Page 376 and 377:
Page 378 and 379:
Page 380 and 381:
Page 382 and 383:
Page 384 and 385:
Page 386 and 387:
Page 388 and 389:
Page 390 and 391:
Page 392:
show all

User Guide - Eurotherm Ltda

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?