RTD, Precision Resistance Temperature Detector
Contents
1. ea udd 01 Ages 5 e 5 udd sx 07 1 9501 uonnjosaJ YUM OLLLLL L 020500001 914 92 43 ISIN 222 19 5 1 N38Hf0D 3 lt uon enqns 5 019Z K2e1n22e enjosqe os pajeas Sd 101515 YOLVINWIS GLY 3012313 3HQ1VH3d4W313ONVISIS3H 531935 Z Q 1H Specifications Series Chapter 3 Installation 3 1 Initial Inspection IET instruments receive a careful mechanical and electrical inspection before shipment Upon receipt verify that the contents are intact and as ordered The instrument should then be given a visual and operational inspection If any shipping damage 1 found contact the carrier and IET Labs If any operational problems are en countered contact IET Labs and refer to the warranty at the beginning of this manual Save all original packing material for convenience in case shipping of the instrument should become necessary 3 2 Installation For a rack mounted model installation in a 19 inch rack may be made using the slots in the rack mount ing ears mounting location that does not expose the unit to excessive heat is recommended For bench models there is no required installation2. e 9522 ay peua 5 BY Buom uaym sajns 3 9429500 ONINYVM L gt Aje idA sadejuns UO JaAjis Aue ADeuNdIe 1594 10 si ul yeaq 5141 Hulsn sKeM 50 01 1 U21IMS seu UI yea1g YUMS 5 3SN3S pu N3HHf D 11 BSN 5 gt 1 5 D 1 LN388R2 9sn N3HHfD 1 pue ASN 5 gt Z 5 0 uon euuo 0 0 0 5 01 03 5 ay 195 unas SOZ 10 SIY uonisod 501 941 ur 0 e Buurnbei 195 ay se os uonne 95 701 pue suonisod 50015 OM seu 5 OL 941 bunmes YDUMS 6897771 65 NS 1000 9 7 Q1H A 0001 00 3ueAn pue 5 LL 10 ur gt 10 days Jad 001 5 666 01 01000 01 10 001 10 001 10
3. 16 Table 5 2 Replaceable Parts EISL 17 Figure 5 2 RTD Series Replaceable Parts 17 Series Chapter 1 INTRODUCTION 1 1 Introduction The RTD Series Precision RTD Resistance Temperature Detector Simulator provides a very broad range of absolute resistance values that replace RTD s thermocouples Thermocouples present a re sistance that depends on the temperature The RTD simulator effectively replaces an RTD to test analyze and calibrate RTD measuring systems The RTD Series simulator is a precision resistance source with excellent characteristics of accuracy stability temperature coefficient and power coeffi cient All these features serve to make it a laboratory resistance standard exceeded in performance only by stand alone standard resistors The special design of the RTD Series provides absolute accuracy and re quires no zero resistance subtraction from any setting Wirewound resistors are used for 1 steps and over The wirewound resistors exhibit stability of better than 10 ppm year improving as they age The low resistance resistors are constructed with resistance wire There 15 a minimum of copper resistance in series to limit temperature coefficient effects The RTD Series employs completely enclosed dust tight very low contact resistance switches They feature solid silver alloy contacts and quadruple l
4. to 55 Storage temperature 40 to 70 Humidity lt 80 RH Switch type Multiple solid silver contacts dust tight diallyl phthalate body To allow continuous rotation a blank position is added on all decades except the 10 decade Specifications Series SPECIFICATIONS CONTINUED Au OE Resistor type Wirewound hermetically sealed low inductance Terminals Four 5 way gold plated tellutium copper binding posts with low thermal emf and low resistance for four terminal Kelvin measurements plus one binding post connected to case for shielding Options RH Rear output is available as an option Specifications Series 10 4 eas e2id 2 2 ainbig 66 61 0 60323 14 100 9 2 1 514 ALY gt 51069 3802 ADVI 8865 915 4 6965 916 19 AN puesi INI 58 131 Ajajes jauuosied dae pue subis 1504 2 5 Bunsnfpe uaym 4 9 s1032npuoo aJeq esn pue e s UaBUOdWOD 12e3u02 pasn gt 5 2 je suauM
5. Since this 15 a high accuracy instrument it is rec ommended that a space be provided that would not expose it to mechanical abuse and keep it maintained at laboratory standard temperatures near 23 Installation 3 3 Repackaging for Shipment Ifthe instrument is to be returned to IET Labs contact the Service Department at the number or address shown on the front cover of this manual to obtain a Returned Material Authorization RMA number and any special shipping instructions or assistance Proceed as follows 1 Attach a tag to the instrument identifying the owner and indicate the service or repair to be accomplished Include the model number the full serial number of the instrument the RMA number and shipping address 2 Wrap the instrument in heavy paper or plastic 3 Protect the front panel and any other protru sions with cardboard or foam padding 4 Place instrument in original container or equally substantial heavy carton 5 Use packing material around all sides of instrument 6 Seal with strong tape or bands 7 Mark shipping container DELICATE INSTRUMENT FRAGILE etc 3 4 Storage If this instrument 15 to be stored for any lengthy period of time it should be sealed in plastic and stored in a dry location It should not be subjected to temperature extremes beyond the specifications Extended expo sure to such temperatures can result in an irreversible change in resistance and requ
6. 41 79 42 21 42 63 43 04 43 45 43 87 44 28 44 70 137 136 135 134 133 132 131 130 129 128 127 126 125 124 123 122 121 120 119 118 117 116 115 114 113 112 111 110 109 108 107 106 105 104 103 102 101 100 99 98 97 96 95 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 75 Ohms 45 11 45 52 45 94 46 35 46 76 47 18 47 59 48 00 48 41 48 82 49 23 49 64 50 06 50 47 50 88 51 29 51 70 52 11 52 52 52 92 53 33 53 74 54 15 54 56 54 97 55 38 55 78 56 19 56 60 57 00 57 41 57 82 58 22 58 63 59 04 59 44 59 85 60 25 60 66 61 06 61 47 61 87 62 28 62 68 63 09 63 49 63 90 64 30 64 70 65 11 65 51 65 91 66 31 66 72 67 12 67 52 67 92 68 33 68 73 69 13 69 53 69 93 70 33 74 73 72 71 60 59 58 57 56 55 54 53 52 51 48 45 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 23 22 21 20 19 18 17 16 15 13 12 Ohms 70 73 71 13 71 53 71 93 72 33 72 73 73 13 73 53 73 93 74 33 74 73 75 13 75 53 75 93 76 33 76 73 77 13 77 52 77 92 78 32 78 72 79 11 79 51 79 91 80 31 80 70 81 10 81 50 81 89 82 29 82 69 83 08 83 48 83 88 84 27 84 67 85 06 85 46 85 85 86 25 86 64 87 04 87 43 87 83 88 22 88 62 89 01 89 40 89 80 90 19 90 59
7. 90 98 91 37 91 77 92 16 92 55 92 95 93 34 93 73 94 12 94 52 94 91 95 30 11 10 9 8 E 6 5 4 3 2 4 3 gt 40 41 42 43 44 45 46 47 48 49 50 Ohms 95 69 96 09 96 48 96 87 97 26 97 65 98 04 98 44 98 83 99 22 99 61 00 00 00 39 00 78 01 17 01 56 01 95 02 34 02 73 03 12 03 51 03 90 04 29 04 68 05 07 05 46 05 85 06 24 06 63 07 02 07 40 07 79 08 18 08 57 08 96 09 35 09 73 0 12 0 51 10 90 1 28 5 54 16 31 6 70 7 08 7 47 7 85 8 24 18 62 9 01 100 101 102 103 104 105 106 107 108 109 110 111 112 113 Ohms 119 78 120 16 120 55 120 93 121 32 121 70 122 09 122 47 122 86 123 24 123 62 124 01 124 39 124 77 125 16 125 54 125 92 126 31 126 69 127 07 127 45 127 84 128 22 128 60 128 98 129 37 129 75 130 13 130 51 130 89 131 27 131 66 132 04 132 42 132 80 133 18 133 56 133 94 134 32 134 70 135 08 135 46 135 84 136 22 136 60 136 98 137 36 137 74 138 12 138 50 138 88 139 26 139 64 140 02 140 39 140 77 141 15 141 53 141 91 142 29 142 66 143 04 143 42 5 15 16 18 119 120 21 122 23 24 25 26 27 128 129 150 151 52 153 55 156 157 159 70 171 172 174 T5 176 Ohms 143 80 144 17 144 55 144 93 145 31 145 68 146 06 146 44 146 81 147 19 147 57 147 94 148 32 148 70 1
8. PRECISION INSTRUMENTS TEST AND MEASUREMENT RTD Series Precision Resistance Temperature Detector RTD Simulator User and Service Manual Copyright O 2014 IET Labs Inc Visit www ietlabs com for manual revision updates RTD Series im November 2014 9 F ietlabs TEL 516 334 5959 FAX 516 334 5988 4 PRECISION INSTRUMENTS TEST AND MEASUREMENT 8 ietlabs TEL 516 334 5959 FAX 516 334 5988 WARRANTY We warrant that this product is free from defects in material and workmanship and when properly used will perform in accordance with applicable IET specifications If within one year after original shipment it is found not to meet this standard it will be repaired or at the option of IET replaced at no charge when returned to IET Changes in this product not approved by IET or application of voltages or currents greater than those allowed by the specifications shall void this warranty IET shall not be liable for any indirect special or consequential damages even if notice has been given to the possibility of such damages THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE N WARNING OBSERVE ALL SAFETY RULES WHEN WORKING WITH HIGH VOLTAGES OR LINE VOLTAGES Dangerous voltages may be present inside this instrument Do not open the case
9. Refer servicing to qualified personnel HIGH VOLTAGES MAY BE PRESENT AT THE TERMINALS OF THIS INSTRUMENT WHENEVER HAZARDOUS VOLTAGES 45 V ARE USED TAKE ALL MEASURES TO AVOID ACCIDENTAL CONTACT WITH ANY LIVE COMPONENTS USE MAXIMUM INSULATION AND MINIMIZE THE USE OF BARE CONDUCTORS WHEN USING THIS INSTRUMENT Use extreme caution when working with bare conductors or bus bars WHEN WORKING WITH HIGH VOLTAGES POST WARNING SIGNS AND KEEP UNREQUIRED PERSONNEL SAFELY AWAY CAUTION DO NOT APPLY ANY VOLTAGES OR CURRENTS THE TERMINALS OF THIS INSTRUMENT IN EXCESS OF THE MAXIMUM LIMITS INDICATED ON THE FRONT PANEL OR THE OPERATING GUIDE LABEL Contents Chapter 1 Introduction e t 1 1 Chapter 2 50601110 811005 2 78 2 Chapter 3 Installati n 6 3 1 initial REESE 6 3 27 Installation 6 3 3 Repackaging for Shipment eren e 6 NM ED E 6 Chapter 4 Operation e 7 41 Initial Inspection and 7 22 7 42 General Considerations ice teret 7 43 Electrcal Considerations oi eret tetigere oer 7 4 3 1 Thermal emf Considerations essere 7 44 Dial 8 4
10. following are some possible choices Resistance Standards or Transfer Standards for 1 Q 100 1000 1 10 100 1 and 10 per step calibrated to 10 ppm IET options include the follow ing models e HATS LR HATS Y SRL Series The 1 and 10 transfer standards optional and are only used to take advan tage if desired of the adjustability of these two decades Precision resistance measurement bridge or multimeter with a transfer accuracy of l ppm Options include e Guildline Model 9975 e Measurements International Model 6000A Maintenance RTD Series ET ESI model 242 242A 242C or 242D e Ahigh precision high stability digi tal multimeter e g Fluke 8508A along with a set of resistance stan dards for ratio mode 5 3 4 Calibration Procedure To calibrate the RTD Series unit proceed as follows l Set up the calibration equipment in the re sistance measurement mode and exercise the switches 10 times in each direction Allow the switches to cool for 15 minutes Confirm the minimum resistance of the unit Allow a confidence band for the uncer tainty of the measuring instrument and Setup Determine the allowable upper and lower limits for each resistance setting of each decade based on the specified accuracy and the confidence band for the RTD being tested Confirm that the resistances fall within these limits If any resistances fall outside
11. screws from the sides of the instrument and remove the housing 3 Using the binding posts in the 4 terminal connection connect RTD Series to a resis tance meter 4 Rotate all knobs approximately 10 times and be careful not to rotate the minimum setting decade beyond the stops Breaking in the switches helps elimi nate any residual contact corrosion resistance 5 Setall dialsto zero except the 10 ohm decade which has a minimum stop at position 1 6 Measure the 100 setting It should bea 100 2 ppm if an adjustment is needed proceed as follows 7 Turn the potentiometer TO on the lowest de cade board either 0 001 or 0 01 board fully clockwise and record the reading 8 Turn the potentiometer TO on the lowest decade board either 0 001 or 0 01 fully counter clockwise and record the reading 9 Setthe potentiometer to obtain the midpoint resistance reading between maximum and minimum 10 Repeat the same process for the 0 01 ohms and 0 1 ohms decades as applicable 11 Setting these TO potentiometers to their mid points will bring the fixed 10 ohms very close to its nominal 12 Re measure 10 O minimum The number should be very close to its nominal If any adjustments are necessary Locate a piece of manganin resistance wire 1 11 on the lowest decade 0 001 or 0 01 board 13 Trim the wire as follows If the 10 2 resis tance is high reduce it by adding a small bit of solder to an exposed port
12. the order of 5 ppm 4 2 4 Thermal emf Considerations The highest quality low emf components are used in the RTD Series series In particular the terminals are made of gold plated tellurium copper which exhibits low emf and low resistance There nevertheless may be some minute thermal emf generated at the user s test leads where they contact the RTD Series bind ing posts This will depend on the test lead material Whenever this is critical brass and iron materials should be avoided This emf will be virtually eliminated 1f a meter with so called True Ohm capability is used Otherwise it may appear as a false component of the dc resistance measurement and can be the order of milliohms 4 3 Dial Setting The 10 decade does not go below the 1 position in order to maintain a precise and constant minimum resistance of 10 O so that no subtraction of zero resis tance is required Excise caution so as not force 100 decade dial below 1 position To set values requiring a 0 in the 10 2 position follow this example for a 205 Q setting set the dials to 1 10 5 0 0 0 Whenever the dials are used in positions 0 9 the resulting resistance is read directly Both the decimal point and the steps are clearly marked on the panel For additional flexibility and range each decade provides a 10 position setting This 10 position on any one decade equals the 1 position on the next higher decade It adds about 1196
13. 1 Minimum resistance O 10 000 10 000 10 00 10 00 Number of decades Absolute accuracy ppm Resolution Tempco max ppm C Stability ppm 24hrs Stability ppm year 1 50 5 3 2 10 Maximum resistance 0 1 111 110 1 111 110 11 111 10 11 111 10 Tempco typical es 4390173 43 9 17 3 43 9 17 3 43 9 17 3 0 At 23 C true ohm measurement 30 70 RH absolute reading SI traceable Switch Setting The 10 Q switch has two stops at positions 1 and 10 Absolute accuracy without zero subtraction is accomplished by having a minimum settable resistance which includes all contact and wiring resistances Absolute accuracy applies for every setting See table above for the minimum settable resistance for any model Minimum settable resistance is implemented by a mechanical stop in one of the decades Maximum Power for rated accuracy 100 mW or 100 mA for 10 000 to 10 999 100 mW per step for the highest decade in use for 11 Q and over Maximum Current 200 mA Breakdown Voltage 1000 V 9 17 3 9 17 5 no zero subtraction required Connection to Terminals 2 terminal devices use H and L CURRENT terminals 3 terminal devices use H CURRENT L CURRENT and G terminals 4 terminal devices use all CURRENT and SENSE terminals Note Ground Strap 1 the only connection between CURRENT and SENSE terminals Environmental conditions Operating temperature 0
14. 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 Operation Ohms 190 45 190 81 191 18 191 54 191 90 192 26 192 63 192 99 193 35 193 71 194 07 194 44 194 80 195 16 195 52 195 88 196 24 196 60 196 96 197 33 197 69 198 05 198 41 198 77 199 13 199 49 199 85 200 21 200 57 200 93 201 29 201 65 202 01 202 36 202 72 203 08 203 44 203 80 204 16 204 52 204 88 205 23 205 59 205 95 206 31 206 67 207 02 207 38 207 74 208 10 208 45 208 81 209 17 209 52 209 88 210 24 210 59 210 95 211 31 211 66 212 02 301 302 303 304 305 306 307 308 309 310 31 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 Ohms 212 37 212 73 213 09 213 44 213 80 214 15 214 5 214 86 215 22 215 57 215 93 216 28 216 64 216 99 217 35 217 70 218 05 218 41 218 76 219 12 219 47 219 82 220 18 220 53 220 88 221 24 221 59 221 94 222 29 222 65 223 00 223 35 223 70 224 06 224 41 224 76 225 11 225 46 225 81 226 17 226 52 226 87 227 22 227 57 227 92 228 27 228 62 228 97 229 32 229 67 230 02 230 37 230 72 231 07 231 42 231 77 232 12 232 47 232 82 233 17 233 52 362 363 364
15. 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 Ohms 233 87 234 22 234 56 234 91 235 26 235 61 235 96 236 31 236 65 237 00 237 35 237 70 238 04 238 39 238 74 239 09 239 43 239 78 240 13 240 47 240 82 241 17 241 51 241 86 242 20 242 55 242 90 243 24 243 59 243 93 244 28 244 62 244 97 245 31 245 66 246 00 246 35 246 69 247 04 247 38 247 72 248 07 248 41 248 76 249 10 249 45 249 79 250 13 250 48 250 82 251 16 251 50 251 85 252 19 252 53 252 87 253 22 253 56 253 90 254 24 254 59 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 Ohms 254 93 255 27 255 61 255 95 256 29 256 63 258 98 257 32 257 66 258 00 258 34 258 68 259 02 259 36 259 70 260 04 260 38 260 72 261 06 261 40 261 74 262 08 262 42 262 76 263 10 263 43 236 77 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 50
16. 49 07 149 45 149 82 150 20 150 57 150 95 151 33 151 70 152 08 152 45 152 83 153 20 153 58 153 95 154 32 154 70 155 07 155 45 155 82 156 19 156 57 156 94 157 31 157 69 158 06 158 43 158 81 159 18 159 55 159 93 160 30 160 67 161 04 161 42 161 79 162 16 162 53 162 90 163 27 163 65 164 02 164 39 164 76 165 13 165 50 165 87 166 24 166 61 166 98 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 Ohms 167 35 167 72 168 09 168 46 168 83 169 20 169 57 169 94 170 31 170 68 171 05 171 42 171 79 172 16 172 53 172 90 173 26 173 63 174 00 174 37 174 74 175 10 175 47 175 84 176 21 176 57 176 94 177 31 177 68 178 04 178 41 178 78 179 14 179 51 179 88 180 24 180 61 180 97 181 34 181 71 182 07 182 44 182 80 183 17 183 53 183 90 184 26 184 63 184 99 185 36 185 72 186 09 186 45 186 82 187 18 187 54 187 91 188 27 188 63 189 00 189 36 189 72 190 09 Operation Platinum Resistance 240 C to 629 C Temperature Coefficient 0 00385 Ohms Ohm C C 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276
17. 5 Power Considerations rep EGRE 8 4 6 Environmental Conditions 8 4 7 Switch Conditioning SES ESER Esia eisa 8 4 8 Meter Shunt Applications sss 9 9 Chapter 5 11 5 1 Maintainability and Reliability 5 aient 1 5 2 Preventive Maintenance cuis a ero 11 Y reo at 11 5 3 1 Calibration Interval iet 1 5 3 2 General 0 12 533 Required Equipment 5 3 e epi e ec ee HER Re HR Ee 12 5 34 Calibration Procedure oe see 12 5 4 Adjustments ei eerta a to EO OU e ER rer 13 5 4 1 Adjustment Considerations seen 13 5 4 2 Adjustment Trimming Procedure sese 14 5 5 Replaceable Parts Lasts eter erede ee ERE e 15 Figures and Tables Figure 1 1 RTD Series Resistance Substitutes 1 Figure 2 1 Typical Operating Guide Affixed to 4 Figure 4 1 Kelvin Bridge Connections 9 Table 5 1 Trimming POlODilomblofe 16 Figure 5 1 Typical Trimmer BOBIU o due
18. 8 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 Ohms 2715 56 275 89 276 23 276 56 276 89 277 23 277 56 277 90 278 23 278 56 278 90 279 23 279 56 279 90 280 23 280 56 280 90 281 23 281 56 281 89 282 23 282 56 282 89 283 22 283 55 283 89 284 22 284 55 284 88 285 21 285 54 285 87 286 21 286 54 286 87 287 20 287 53 287 86 288 19 288 52 288 85 289 18 289 51 289 84 290 17 290 50 290 83 291 16 291 49 291 81 292 14 292 47 292 80 293 13 293 46 293 79 294 11 294 44 294 77 295 10 295 43 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 313 59 313 91 314 24 314 56 314 88 315 20 C 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 RTD Series Ohms 315 52 315 84 316 16 316 48 316 80 317 12 317 44 317 76 318 08 318 40 318 72 319 04 319 36 319 68 319 99 320 31 320 63 320 95 321 27 321 59 321 91 322 22 322 54 322 86 Series 10 Chapter 5 MAINTENANCE 5 1 Maintainability an
19. ctice when high accuracy is required This effect is of the order of less than 1 mQ So it may be ignored whenever measurements of that magnitude are not important To perform this breaking in simply rotate each switch seven to ten times in each direction with the exception of the 10 Q decade switch which should not be rotated beyond the stops 4 7 PT 100 Temperature Charts One of the primary applications of the RTD Series is as calibration of temperature equipment that uses PT 100 Thermocouples Temperature conversion charts are show on the next two pages Series Platinum Resistance 200 C to 239 C Temperature Coefficient 0 00385 Ohms Ohm C 200 199 198 197 196 195 194 193 192 191 190 189 188 187 186 185 184 183 182 181 180 179 178 177 176 175 174 173 172 171 170 169 168 167 166 165 164 163 162 161 160 159 158 157 156 155 154 153 152 151 150 149 148 147 146 145 144 143 142 141 140 139 138 Ohms 18 49 18 93 19 36 19 79 20 22 20 65 21 08 21 51 21 94 22 37 22 80 23 23 23 66 24 09 24 52 24 94 25 37 25 80 26 23 26 65 27 08 27 50 27 93 28 35 28 78 29 20 29 63 30 05 30 47 30 90 31 32 31 74 32 16 32 59 33 01 33 43 33 85 34 27 34 69 35 11 35 53 35 95 36 37 36 79 37 21 37 63 38 04 38 46 38 88 39 30 39 71 40 13 40 55 40 96 41 38
20. d Reliability It is possible to maintain Model RTD Series indefi nitely Itis reliable due to its closed design and sealed switches and resistors It is possible to adjust the unit if necessary because it has adjustable decades for 1 Q decades and above and resistance wire for lower decades which can be trimmed The unit is resistant to electromagnetic interference EMI because of its metal enclosure 5 2 Preventive Maintenance Keep the unit in a clean environment This will help prevent possible contamination The Model RTD Series is packaged in a closed case and uses completely sealed switches This limits the entry of contaminants and dust to the inside of the switches Ifit is maintained in a clean or air condi tioned environment cleaning will seldom be required Should cleaning be needed 1 Remove the 4 housing screws from the side of the instrument and remove the housing 2 Remove any dust or debris using optical grade dry compressed air or a clean brush 3 Replace the housing and reattach the 4 hous ing screws The front panel should be periodically cleaned to eliminate any leakage paths from near or around the binding posts To clean the front panel Wipe the front panel clean using alcohol and a lint free cloth 5 3 Calibration The Model RTD Series may be employed as a stand alone instrument or as an integral component of a system If used as part of a system it should be calibrated as part of the ov
21. eaf silver alloy wipers which keep switch contact resis tance to under 1 per decade and more impor tantly keep switch contact resistance reproducible insuring repeatable instrument performance High quality low resistance heavy duty gold plated tellurium copper binding posts minimize the thermal emf effects which would artificially reflect a change In dc resistance measurements All other conductors Introduction within the instrument as well as the solder employed contain no metals or junctions that contribute to ther mal emf problems The RTD Series is designed to allow very convenient maintenance of calibration over time The decades for the 0 001 Q through 0 1 Q steps are adjusted with convenient potentiometers Trimming of the higher decades is also possible With a resolution as low as 1 and a maximum available resistance of over 1111 11 the RTD Series may be employed for exacting precision mea surement applications requiring high accuracy and stability They can be used as components of dc and low frequency ac bridges for calibration and as well as RTD simulators Figure 1 1 RTD Series Precision RTD Simulator Series Chapter 2 SPECIFICATIONS For convenience to the user the pertinent specifications are given in a typical OPERATING GUIDE like the one shown in Figure 2 1 affixed to the case of the instrument SPECIFICATIONS RTD Z 6 001 RTD X 6 001 RTD Z 6 01 RTD X 6 0
22. erall system to provide an optimum system calibration Ifthe RTD Series is employed as a stand alone device the following should be observed Calibration Interval General Considerations Required Equipment Calibration Procedure 5 3 1 Calibration Interval The recommended RTD Series calibration interval is twelve 12 months If the instrument is used to transfer resistance values only recalibration is not required assuming that there has been no drastic change in the deviations of any individual resistors Maintenance 5 3 2 General Considerations Before starting the calibration procedure you need to consider the following Calibration environment should be 23 C and less than 5095 relative humidity Test instruments should be sufficiently more accurate than the RTD Series unit and or the uncertainty ofthe measurement instrumenta tion has to be considered in the calibration Test Uncertainty Ratio TUR The testing equipment and the RTD Series unit should stabilize at laboratory conditions for at least 24 hours Kelvin type 4 wire test leads should be used to obtain accurate low resistance measurements Steps should be taken to minimize thermal emf effects such as using a meter with True Ohm capacity Accepted metrology practices should be followed 5 3 3 Required Equipment Many combinations of standards transfer standards meters and bridges may be used to calibrate this in strument The
23. ion of the wire If the 10 resistance is low gently file the wire in one spot Make these steps carefully and slowly allowing the wire to cool down and re measuring Maintenance 14 Once the 10 adjustment is completed follow the Table 5 1 below for each decade less than 0 10 15 Use Fig 5 1 to locate the potentiometers on the decades 0 001 Q 0 01 and 0 10 16 Replace the housing and reinstall the 4 hous ing screws Setting on the RTD Z Potentiometer on RTD Z PC Board Trim Potentiom eters Figure 5 1 Typical Trimmer Board Maintenance RTD Series 13 Series 5 5 Replaceable Parts List SBm ngeetRed O 2 se10o5k Binding Post Black s Ta 060008 Knob Assembly _______________ Not Shown RTD Seres3100 ro SSCS Not Shown RTD 4000 001 1 mO step Decade Switch Assembly Not Shown RTD 4000 0 01 10 Decade Switch Assembly Not Shown RTD 40001 0 1 100 Decade Switch Assembly Not Shown RTD 4000 1 1 step Decade Switch Assembly Not Shown RTD 4000 10 10 Decade Switch Assembly Not Shown RTD 4000 100 10 Decade Switch Assembly Table 5 2 Replaceable Parts List Figure 5 2 RTD Series Replaceable Parts 14 Maintenance
24. ire recalibration Series Chapter 4 4 1 Initial Inspection and Setup This instrument was carefully inspected before ship ment It should be in proper electrical and mechanical order upon receipt An OPERATING GUIDE is attached to the case of the instrument to provide ready reference to specifications 4 2 Connection Four high performance low resistance heavy duty gold plated tellurium copper binding posts minimize the thermal emf effects which would artificially reflect a change in dc resistance measurements AII other conductors within the instrument as well as the solder employed contain no metals or junctions that contribute to thermal emf problems These terminals are labeled CURRENT H CURRENT L SENSE H and SENSE L provide two current and two potential terminals respectively In accordance with industry standards the two SENSE terminals are internally connected to the RTD circuit and the external shorting links must be connected for 4 terminal measurement as this 1s the only connec tion between CURRENT and SENSE terminals A fifth metal binding post labeled GND Ground is connected to the case and may be used as a guard or shield terminal When 4 terminal measurements are used it is best to use banana plugs rather than lugs because the center conductor of a banana plug is closer to the center of the banana jack Lugs may result is small differences from the calibrated values of
25. these limits the associated switch assembly may require adjustment or replacement 11 Series 12 5 4 Adjustments If one or more resistances fall outside the limits the associated resistor should be adjusted There is a trimming network provided for each resistance in these ranges These may be accessed by removing the housing and accessing the particular decade PC board Adjust the resistors from lowest to highest The order of decades does not matter Whereas it is possible to adjust any one resistance step note that the n step of a decade is the sum of resistances 1 through so that errors are cumula tive Itis therefore recommended that whenever any resistance of a particular decade is adjusted that all the resistances of that decade be tested and adjusted as required To adjust any ofthe resistances the following should be observed Adjustment considerations e Adjustment procedure 5 4 1 Adjustment Considerations Before adjusting or trimming any resistances observe the following N CAUTION N The RTD Series front panel GND binding post should be connected to the test instrument s ground point The equipment measuring the unit should conform to the guidelines provided in Section 5 3 5 4 2 Adjustment Trimming Procedure To trim or adjust any resistances proceed as follows 1 Stabilize RTD Series at laboratory tempera ture of 23 C for at least 8 hours 2 Remove the 4 housing
26. to the nominal total decade resistance Operation To determine the resistance obtained when one more 10 settings are used simply add 1 to the next higher decade For example and a setting of 10 10 10 10 10 10 becomes i 10000 0 10 1000 0 10 100 0 10 10 0 10 1 0 01 0 1 1 1 1 1 1 1 Use caution so as not to damage the switch To set values requiring a 0 in the 10 Q position follow this example for a 205 Q setting set the dials to 1 10 5 0 0 0 4 4 Power Considerations To maintain the maximum possible accuracy and precision power applied to the RTD Series should be kept as low as possible preferably below 0 1 W For best protection of the instrument it is advisable to limit the input power to 0 5 W This may be imple mented with a series resistor or fuse 4 5 Environmental Conditions For optimal accuracy the decade box should be used in an environment of 23 C It should be allowed to stabilize at that temperature for at least four hours after any significant temperature variation Humidity should be maintained at laboratory condi tions of lt 80 RH Operation RTD Series 4 6 Switch Conditioning The switch wipers employed in this unit are self cleaning They have solid silver alloy contacts After being left idle the wipers and contacts must be conditioned or broken in again to remove the film of silver oxide that develops over time This is standard metrology pra
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