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OPERATING INSTRUCTIONS
FP-RLY-420
8-Channel, SPST Relay Module
These operating instructions describe the installation, features, and
characteristics of the FP-RLY-420. For details on configuring and
accessing the FP-RLY-420 over a network, refer to the user manual
for the particular FieldPoint network module you are using with
the FP-RLY-420.
Features
The FP-RLY-420 is a FieldPoint relay output module with the
following features:
• Eight Single-Pole Single-Throw (SPST) relay channels
• Swit
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module. The maximum number of terminal bases per bank multiplied by 1 watt is the total power the network module can supply. For example, an FP-1000 or FP-1001 can support nine terminal bases (9*1 W = 9 W). Next, refer to the specifications section in the operating instructions for the I/O modules. Use the Power from Network Module specification. For example, a bank of modules consisting of four FP-RLY-420 and five FP-DI-301 modules requires a total of 8.4 W from the FieldPoint network mo
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Field Wiring The terminal base has connections for each of the eight relay channels and an external supply to power field devices. Each relay channel of the FP-RLY-420 has two terminals: N.O. (Normally Open) and I.C. (Isolated Common). The external supply is not needed for the internal 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 the V and C
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Figures 2a and 2b show examples of basic wiring connections. + – VC V sup Load N.O. I.C. COM N.O. Load + V sup I.C. – N.O. I.C. N.O. + Load COM I.C. – Load a. Total Current Less b. Total Current Greater Than 6 Amps Than 6 Amps Figure 2. Basic Field Connection (Two Channels Shown) Relay Output Circuit The outputs of the FP-RLY-420 consist of Form A electromechanical relays. The power-up state is off (open) to ensure safe installation. In the ON state, the N.O. and I.C. contacts connect togeth
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Figure 3 shows the diagram of one channel’s relay output circuit. V V sup N.O. I.C. COM C Figure 3. Relay Output Circuit The maximum switching capacity of each relay is 3 A up to 250 VAC or 35 VDC. To switch greater DC voltages, refer to Figure 4. 3 2.5 2 Safe Operating Current Region 1.5 (Amps) 1 .5 04 20060 80 100 120 DC Volts Figure 4. Maximum Current vs. DC Volts Contact Protection for Inductive Loads When inductive loads are connected to the relays, a large counter-electromotive force
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In addition, the FP-RLY-420 contains its own internal protection MOV to prevent excessively high voltage from being applied across the contacts. The MOV is located between the N.O. and I.C. contacts of each relay, but National Instruments still recommends the use of a protection circuit across your inductive load. Guidelines for Selecting Contact 1 Protection Circuits Proper selection is critical as the use of a contact-protection device can extend contact life. When mounting the protectio
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Diode 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. Load For smaller voltages, use reverse breakdown voltage of 2 to 3 times power supply voltage. CR Circuits Diagram Notes Circuit A is suitable for AC or DC applications, but if used with AC voltage, impedance of the load should be smalle
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In-Rush Current The type of load and its in-rush current characteristics, together with switching frequency, can cause contact welding. For loads with in-rush current, measure the steady state current and in-rush current to determine the proper relay. Some typical types of loads and the in-rush current they create are summarized in the following chart. Type of Load In-Rush Current Resistive load Steady-state current Solenoid load 10 to 20 times the steady-state current Motor load 5 to 10 ti
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After the module has been inserted into a terminal base (and power is applied), the green POWER indicator lights and the FP-RLY-420 informs the network module of its presence. When the network module recognizes the FP-RLY-420, the network module sends initial configuration information to the FP-RLY-420. After receiving this initial information, the green READY indicator lights and the FP-RLY-420 is in its normal operating mode. In addition to the green POWER and READY indicators, each ch
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•Do not share the external supply voltages (V and C on the terminal base) with other devices (including other FieldPoint devices) unless those devices are also isolated from human contact. • As with any hazardous voltage wiring, ensure that all wiring and connections meet with applicable electrical codes or common sense practices. Mount terminal bases in an area, position, or cabinet that prevents accidental or unauthorized access to wiring with hazardous voltages. • The isolation of the
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Maximum switching frequency Mechanical .................................20 operations per second Electrical.....................................1 operation per second at maximum load Relays operate time...........................6 ms typical, 8 ms max. Relays release time ...........................3 ms typical, 4 ms max. Relay bounce time ............................3 ms max. Contact material................................Gold-plated silver cadmium oxide Isolation (CH–GND and CH–CH)....3,000
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Mechanical Dimensions Figure 6 shows the mechanical dimensions of the FP-RLY-420 installed onto a terminal base. Dimensions are given in inches [millimeters]. 4.22 [107.19] 4.31 [109.5] 3.60 [91.44] Figure 6. Mechanical Dimensions
