National Instruments cFP-RTD-122 manuale d’uso

323348B-01 April 2003 © 2002–2003 Nat ional Instr uments Corp. All ri ghts reserved. FieldPoint ™, National Instruments ™, NI™, and ni. com™ are tradema rks of National I nstruments Cor poration. Produc t and com pany n ames m entioned herein are trad emar ks or trad e names o f their respecti ve com panies . For patent s covering Nation[...]

FP-RTD-122 and cFP-RTD-122 2 ni.com Installing th e FP-RTD-122 The FP-R TD-122 mounts on a Fie ldPoi nt termin al base (FP-TB - x ), which pro vides operating po wer to the module. Inst alling th e FP-R TD-122 onto a po wered termin al base do es not disru pt the opera tion of the ba nk. T o install the F P-R TD-122, refer to Figure 1 an d complete[...]

© National Instruments Corp. 3 FP-RTD-122 and cFP-RTD-122 T o install the cFP -R TD-122, refer to Figure 2 and complete the follo wing steps: 1. Alig n the captive screws on the cFP-RTD-122 with the hol es on the bac kplane. The ali gnment keys on the cFP- R TD-12 2 prev ent backward ins ertion. 2. Press firmly to sea t the cFP-R TD-1 22 on the ba[...]

FP-RTD-122 and cFP-RTD-122 4 ni.com Wiring the [c]FP-R TD-122 The FP-TB- x terminal bases have connection s for each o f the eight input c hannels on the FP-R T D-122. Th e cFP-CB- x co nnector blocks pr ovide the same connect ions for t he cFP-R TD-122. T able 1 li sts t he term inal as sig nment s for t he si gnals asso ciat ed with each cha nnel[...]

© National Instruments Corp. 5 FP-RTD-122 and cFP-RTD-122 Figure 3 . [c]F P-RTD-122 Inpu t Circuitry T aking Measurements from Three-Wire R TDs Three-wire R TDs often ha ve a wire of one color (usually white, sometimes re d) for po siti ve e xcitation, and tw o wires of another color (usually red, sometim es black). Conn ect the positive ex citati[...]

FP-RTD-122 and cFP-RTD-122 6 ni.com Figure 5. Fou r -Wire RTD Connection s on One Channel T aking Measurements from T wo-Wire R TDs Connect eith er wire of a two-wire R TD to the EX+ terminal and the other wire to the COM term inal, and co nnect a sho rt jumper wire between th e COM and SENSE terminals. Figure 6. T wo-Wire RTD Connectio ns on One C[...]

© National Instruments Corp. 7 FP-RTD-122 and cFP-RTD-122 Converting Resistance M easurements to T emperatu re Measureme nts The [c]FP -R TD-122 has b uilt-in line arization algo rithms for platinu m R TDs of ei ther 100 or 1,00 0 Ω no minal resista nce, and for si x TCR (or a lpha, α ) values. The TCR is the av erage temperature co eff icient [...]

FP-RTD-122 and cFP-RTD-122 8 ni.com The [c]FP-R TD-122 uses a l inearizati on curve known as the Callendar-V an Dusen equat ion to measur e the temperature of R TDs. The equat ion is as follows: T emper atures belo w 0 ° C: R T = R 0 [1 + A × T + B × T 2 + C × T 3 × ( T – 100 °C )] T emper atur es a bo v e 0 ° C: R T = R 0 [1 + A × T + B [...]

© National Instruments Corp. 9 FP-RTD-122 and cFP-RTD-122 ef fects of th e lea ds. The only residua l error s ar e tho se ca us ed b y mismatchi ng the EX+ and COM lead s. Most R TDs have lead resistances wi thin 5% of each ot her, so the com pensation of the [c]FP-R TD-122 corrects for 95% or more of the errors introduced by lead resistanc es. Th[...]

FP-RTD-122 and cFP-RTD-122 10 ni.com Upgradin g the FieldPoi nt Firmw are Y ou may need t o upgra de the Fiel dPoin t firmware when y ou add new I/O module s to the Fi eldPo int syst em. For inf ormat ion on deter mining which f irmwar e you need an d ho w to upgr ade you r firmware, go to ni.com/info and enter fpmatrix . Isolation and Sa fety Guid[...]

© National Instruments Corp. 11 FP-RTD-122 and cFP-RTD-122 • Oper ate the [c]FP -R TD-122 only at or belo w Pollution Degree 2. Po llut ion Degree 2 mea ns tha t only no ncon ductive pollu tion oc curs in most case s. Occasion ally , howe ver , a tempor ary cond uctivity caused by con densati on must be expected. • Refer to t he Fiel dPoint pr[...]

FP-RTD-122 and cFP-RTD-122 12 ni.com Offset error , 4,00 0 Ω range 15 to 35 °C ......... ............... ... 0.2 Ω ty p, 0. 7 Ω ma x – 40 to 70 °C .............. ........... 0.8 Ω typ, 4.0 Ω ma x Gain error 15 to 35 °C ............. ........... ... 0.01% ty p, 0. 02% max – 40 to 70 °C ........... ........... ... 0.07% typ, 0. 1% m[...]

© National Instruments Corp. 13 FP-RTD-122 and cFP-RTD-122 Maximum altitud e ........... ........... ....... 2,000 m; a t higher a ltitude s the isolat ion v oltage r atings must be lowered Pollutio n De gree ......... ....... ........... ... 2 Shock an d Vibratio n Thes e speci fic ations apply on ly to the cFP -R TD- 122. NI recommends Compact F[...]

FP-RTD-122 and cFP-RTD-122 14 ni.com CE Complia nce This produ ct meets the essential re quirements of applicab le European Direct iv es, as amended for CE Mark ing, as follows: Lo w-V oltage Dire cti ve (safety)......... 73/23 /EEC Electrom agnetic Compati bility Directi ve (EMC ) ............. ....... ........... 89/33 6/EEC Note Ref er to t he D[...]

© National Instruments Corp. 15 FP-RTD-122 and cFP-RTD-122 Go to ni.com/support for the most current m anuals, example s, and t rouble shootin g info rmati on. For telephone supp ort in the United States, crea te your service request at ni.com/ask and follow the calling instructions or dial 512 795 8248. F or telep hone support outside the United [...]