National Instruments EIGHT CHANNEL SPST RELAY MODULE manual


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Table of contents for the manual

  • Page 1

    323617A-01 May 2003 © 2003 National I nstruments Corp. Al l rights res erved. FieldPoint™, Nati onal Instruments™, NI™, and™ are trademarks of National Instruments Corporation. Product and company names ment ioned herein are trademark s or trade names of their respecti ve companies. For patents covering National Inst ruments product[...]

  • Page 2

    cFP-RLY-421 2 Before you conf igure a FieldPoint system that uses a cFP-RL Y -421 module, calculate the total power consumption of the I/O modules on the FieldPoint bank. Y ou ca n find the po wer requirement specification in the operating inst ructions for ea ch I/O module . The maximum power the netw ork module can supply is specified in t[...]

  • Page 3

    © National Instruments Corp. 3 cFP-RLY-421 Figure 1. Installing the cFP-RL Y -421 Wiring the cFP-RL Y -421 The cFP-CB- x connector block has conne ctions for each of the eight cFP-RL Y -421 relay channels and for an external supply to power f ield devices. If you are using the cFP-RL Y - 421 in a hazardous voltage application, you mu st use the cF[...]

  • Page 4

    cFP-RLY-421 4 T able 1 li sts the terminal assign ments for the signals of each channel. All of the COM terminals are conne cted internally and all of the V SUP terminals are connected inte rnally . NI does not recommend using them with the cFP-RL Y -421. Caution Cascading power between two modules defeats isolation between those modules. Ca[...]

  • Page 5

    © National Instruments Corp. 5 cFP-RLY-421 Connecting Loads to the cFP-RL Y -421 W ire an external po wer supply to the load and IC terminal of the individu al channel as shown in Figure 2. This method of wiring keeps the electrical connections of the cFP-RL Y -421 within safe current limits. Figure 2. Connecting a Load The cFP-RL Y -421 has eight[...]

  • Page 6

    cFP-RLY-421 6 In addition, the cFP-RL Y -421 has internal protection MO Vs to pre vent excessiv ely high voltag e from being applied across the contacts. The MO Vs are located between the NO and IC contacts of each relay . Howe ver , National Instruments still recommends the use of a protection circuit across an inductive load. The flyback p[...]

  • Page 7

    © National Instruments Corp. 7 cFP-RLY-421 Diode Circuit CR Circuits Varistor Circuit Diagram Notes Use in DC applications only . Compared to RC type, circuit delays release time (2 to 5 times values stated in catalog). For lar ger voltages, use diode with rev erse breakdo wn 10 times circu it voltage an d forward load circuit. For smaller v oltag[...]

  • Page 8

    cFP-RLY-421 8 In-Rush Current The type of l oad and its in-rush current charac teristics, together with switching frequency , can ca use contact welding. For loads with in-rush current, measure the steady state current and in-rush current to determine the proper rela y . Some typical types of loads and the in-rush current they create are sum[...]

  • Page 9

    © National Instruments Corp. 9 cFP-RLY-421 Upgrading the FieldPoint Firmware Y ou may need to upgrade the FieldPoint f irmware when you add ne w I/O modules to the FieldPoi nt system. For information on determining which fi rmware you need and ho w to upgrade the firmw are, go to and enter fpmatrix . Isolation and Sa fety Guidelines Ca[...]

  • Page 10

    cFP-RLY-421 10 •D o not share the exter nal supply voltages (the V and C terminals) with other de vices (including othe r FieldPoint de vices), unless those devices ar e isolated from human contact. • Y ou must connect the protecti ve ea rth (PE) ground terminal on the cFP-BP- x backplane to the syst em safety ground. The backplane PE gr[...]

  • Page 11

    © National Instruments Corp. 11 cFP-RLY-421 Specifications The follo wing specifications ar e typical for a range of – 40 to 60 °C unless otherwise noted. Relay Characteristics Number of channels ..................... ..... 8 Relay type ......... ...................... .......... 1 SPST , nonlatching Maximum switching ca pacity (resisti ve load[...]

  • Page 12

    cFP-RLY-421 12 Physical Indicators ..... .............. ........... ........... . Green POWER and READY indicators, 8 green output state indicators W eight cFP-RL Y -421 .................... .......... 130 g (4.5 oz) Power Requirements Power from network modul e ............ 1,700 mW Isolation Voltage Maximum isolation v oltage .............[...]

  • Page 13

    © National Instruments Corp. 13 cFP-RLY-421 Safety This product is designed to meet the requirements of the following standards of safety for electric al equipment for measurement, control, and laboratory use: • IEC 61010-1, EN 61010-1 • UL 3121-1, UL 61010C-1 • CAN/CSA C22.2 No. 1010.1 For UL, hazardous location, and othe r safety certifica[...]

  • Page 14

    cFP-RLY-421 14 Where to Go for Support For more information about settin g up the FieldPoint system, refer to these National Instruments documents: • FieldPoint network module user manual • Other FieldPo int I/O m odule operating instructions • FieldPoint connector bl ock operating instructions Go to for the most current[...]