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National Instruments Corp.

7

FP-RLY-420

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 larger voltages, use diode with reverse 
breakdown 10 times circuit voltage and 
forward load circuit.

For smaller voltages, use reverse breakdown 
voltage of 2 to 3 times power supply voltage.

Diagram

Notes

Circuit A is suitable for AC or DC 
applications, but if used with AC 
voltage, impedance of the load 
should be smaller than the CR 
circuit’s. Do not utilize for timer 
loads, as leakage current can cause 
faulty operations.

Circuit B is suitable for AC or DC. 
If the load is a relay or solenoid, 
release times lengthen. Effective 
when connected to both contacts, 
power supply voltage across the 
load is 100 to 200 V. 

Diagram

Notes

Effective for AC and DC 
applications.

Circuit slightly delays release time. 
Effective when connected to both 
contacts, power supply voltage 
across the load is 100 to 200 V.

Load

Load

Load

Load

Содержание FP-RLY-420

Страница 1: ...output module with the following features Eight Single Pole Single Throw SPST relay channels Switching capacity 3 A at 35 VDC or 250 VAC On Off LED indicators Hot plug and play operation 3 000 V inpu...

Страница 2: ...Installation The FP RLY 420 mounts on a FieldPoint terminal base FP TB xx unit The hot plug and play operation of the FP RLY 420 allows you to install it onto a powered terminal base without disturbi...

Страница 3: ...ternal operation of the FP RLY 420 however you may connect an external supply to power field devices by connecting to the V and C terminals of the terminal base If you connect an external supply to th...

Страница 4: ...contacts connect together to form a short circuit Choose the impedance of the loads so that the current switched by any one channel in the ON state is no more than 3 A In the ON state there is an eff...

Страница 5: ...nter electromotive force may occur at relay switching time because of the energy stored in the inductive load These flyback voltages can severely damage the relay contacts and greatly shorten the life...

Страница 6: ...the protection device always locate it near the immediate area of the load or contact Typically you should mount a protective device within 18 in of the load or contact Typically contact protection ci...

Страница 7: ...otes Circuit A is suitable for AC or DC applications but if used with AC voltage impedance of the load should be smaller than the CR circuit s Do not utilize for timer loads as leakage current can cau...

Страница 8: ...abel and status indicators You can remove the insertable label to see wiring diagrams for the input channels Figure 5 Status Indicators and Module Label Type of Load In Rush Current Resistive load Ste...

Страница 9: ...ne of the terminal base with an isolation barrier designed and tested to protect against fault voltages of up to 3000 Vrms In addition the FP RLY 420 provides double insulation compliant to UL and IEC...

Страница 10: ...ed for normal operating voltages of 250 Vrms Do not use the FP RLY 420 as the sole isolating barrier between human contact and working voltages of more than 250 Vrms Specifications The following speci...

Страница 11: ...only 250 Vrms designed per IEC 1010 as double insulated Physical Indicators Green POWER and READY indicators 8 green output state indicators Weight 160 g 5 6 oz Power Requirements Power from network...

Страница 12: ...Dimensions Figure 6 shows the mechanical dimensions of the FP RLY 420 installed onto a terminal base Dimensions are given in inches millimeters Figure 6 Mechanical Dimensions 4 31 109 5 3 60 91 44 4...

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