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National Instruments FieldPoint cFP-RTD-122 Operating Instructions Manual

Manual is about: Eight-Channel Three-Wire RTD and Resistance Input Modules

Summary of FieldPoint cFP-RTD-122

  • Page 1

    323348b-01 april 2003 © 2002–2003 national instruments corp. All rights reserved. Fieldpoint™, national instruments™, ni™, and ni.Com™ are trademarks of national instruments corporation. Product and company names mentioned herein are trademarks or trade names of their respective companies. For paten...

  • Page 2

    Fp-rtd-122 and cfp-rtd-122 2 ni.Com installing the fp-rtd-122 the fp-rtd-122 mounts on a fieldpoint terminal base (fp-tb- x ), which provides operating power to the module. Installing the fp-rtd-122 onto a powered terminal base does not disrupt the operation of the bank. To install the fp-rtd-122, r...

  • Page 3

    © national instruments corp. 3 fp-rtd-122 and cfp-rtd-122 to install the cfp-rtd-122, refer to figure 2 and complete the following steps: 1. Align the captive screws on the cfp-rtd-122 with the holes on the backplane. The alignment keys on the cfp-rtd-122 prevent backward insertion. 2. Press firmly ...

  • Page 4

    Fp-rtd-122 and cfp-rtd-122 4 ni.Com wiring the [c]fp-rtd-122 the fp-tb- x terminal bases have connections for each of the eight input channels on the fp-rtd-122. The cfp-cb- x connector blocks provide the same connections for the cfp-rtd-122. Table 1 lists the terminal assignments for the signals as...

  • Page 5

    © national instruments corp. 5 fp-rtd-122 and cfp-rtd-122 figure 3. [c]fp-rtd-122 input circuitry taking measurements from three-wire rtds three-wire rtds often have a wire of one color (usually white, sometimes red) for positive excitation, and two wires of another color (usually red, sometimes bla...

  • Page 6

    Fp-rtd-122 and cfp-rtd-122 6 ni.Com figure 5. Four-wire rtd connections on one channel taking measurements from two-wire rtds connect either wire of a two-wire rtd to the ex+ terminal and the other wire to the com terminal, and connect a short jumper wire between the com and sense terminals. Figure ...

  • Page 7

    © national instruments corp. 7 fp-rtd-122 and cfp-rtd-122 converting resistance measurements to temperature measurements the [c]fp-rtd-122 has built-in linearization algorithms for platinum rtds of either 100 or 1,000 Ω nominal resistance, and for six tcr (or alpha, α ) values. The tcr is the averag...

  • Page 8

    Fp-rtd-122 and cfp-rtd-122 8 ni.Com the [c]fp-rtd-122 uses a linearization curve known as the callendar-van dusen equation to measure the temperature of rtds. The equation is as follows: temperatures below 0 ° c: r t = r 0 [1 + a × t + b × t 2 + c × t 3 × ( t – 100 °c)] temperatures above 0 ° c: r t...

  • Page 9

    © national instruments corp. 9 fp-rtd-122 and cfp-rtd-122 effects of the leads. The only residual errors are those caused by mismatching the ex+ and com leads. Most rtds have lead resistances within 5% of each other, so the compensation of the [c]fp-rtd-122 corrects for 95% or more of the errors int...

  • Page 10

    Fp-rtd-122 and cfp-rtd-122 10 ni.Com upgrading the fieldpoint firmware you may need to upgrade the fieldpoint firmware when you add new i/o modules to the fieldpoint system. For information on determining which firmware you need and how to upgrade your firmware, go to ni.Com/info and enter fpmatrix ...

  • Page 11

    © national instruments corp. 11 fp-rtd-122 and cfp-rtd-122 • operate the [c]fp-rtd-122 only at or below pollution degree 2. Pollution degree 2 means that only nonconductive pollution occurs in most cases. Occasionally, however, a temporary conductivity caused by condensation must be expected. • refe...

  • Page 12

    Fp-rtd-122 and cfp-rtd-122 12 ni.Com offset error, 4,000 Ω range 15 to 35 °c ........................... 0.2 Ω typ, 0.7 Ω max –40 to 70 °c......................... 0.8 Ω typ, 4.0 Ω max gain error 15 to 35 °c ........................... 0.01% typ, 0.02% max –40 to 70 °c......................... 0.07%...

  • Page 13

    © national instruments corp. 13 fp-rtd-122 and cfp-rtd-122 maximum altitude............................. 2,000 m; at higher altitudes the isolation voltage ratings must be lowered pollution degree .............................. 2 shock and vibration these specifications apply only to the cfp-rtd-122...

  • Page 14

    Fp-rtd-122 and cfp-rtd-122 14 ni.Com ce compliance this product meets the essential requirements of applicable european directives, as amended for ce marking, as follows: low-voltage directive (safety)......... 73/23/eec electromagnetic compatibility directive (emc) ............................... 8...

  • Page 15

    © national instruments corp. 15 fp-rtd-122 and cfp-rtd-122 go to ni.Com/support for the most current manuals, examples, and troubleshooting information. For telephone support in the united states, create your service request at ni.Com/ask and follow the calling instructions or dial 512 795 8248. For...