National Instruments cFP-RLY-421 User manual

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FieldPoint Operating Instructions
cFP-RLY-421
Eight-Channel SPST Relay Module
These operating instructions describe how to install and use the
National Instruments cFP-RLY-421 relay module, revision
185151C-01 and later. For information about installing and using
earlier revisions of the cFP-RLY-421, refer to document number
323617B-01. Earlier revisions of the cFP-RLY-421 display the
following symbol on the module label: .
For information about configuring and accessing the cFP-RLY-421
over a network, refer to the user manual for the FieldPoint network
module you are using.
Features
The cFP-RLY-421 is a Compact FieldPoint relay output module
with the following features:
• Eight single-pole single-throw (SPST) relay channels
• Switches up to 1.5 A at 40 VDC or 250 VAC
• –40 to 55 °C operation
• 250 Vrms CAT II continuous channel-to-ground isolation,
verified by 2,300 Vrms, 5 s dielectric withstand test
• Hot swappable
Installing the cFP-RLY-421
The cFP-RLY-421 mounts on a Compact FieldPoint backplane
(cFP-BP-x), which provides operating power to the module.
Installing the cFP-RLY-421 onto a powered backplane does not
disrupt the operation of the bank.
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cFP-RLY-421 2 ni.com
To install the cFP-RLY-421, refer to Figure 1 and complete the
following steps:
1. Align the captive screws on the cFP-RLY-421 with the holes
on the backplane. The alignment keys on the cFP-RLY-421
prevent backward insertion.
2. Press firmly to seat the cFP-RLY-421 on the backplane.
3. Using a number 2 Phillips screwdriver with a shank of at least
64 mm (2.5 in.) length, tighten the captive screws to 1.1 N ⋅m
(10 lb ⋅in.) of torque. The nylon coating on the screws prevents
them from loosening.
Figure 1. Installing the cFP-RLY-421
1 cFP I/O Module
2 Captive Screws
3 cFP Controller Module
4 Screw Holes
5 cFP Backplane
4
4
3
2 1
5
5
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© National Instruments Corp. 3 cFP-RLY-421
Wiring the cFP-RLY-421
The cFP-CB-xconnector block has connections for each of the
eight cFP-RLY-421 relay channels and for an external supply to
power field devices. If you are using the cFP-RLY-421 in a
hazardous voltage application, you must use the cFP-CB-1
connector block or a suitable hazardous voltage cable. A hazardous
voltage is a voltage greater than 42.4 Vpeak or 60 VDC.
Caution Ensure that hazardous voltage wiring is
performed only by qualified personnel adhering to local
electrical standards.
Each relay channel of the cFP-RLY-421 has two terminals:
one NO (normally open) and one IC (isolated common).
Table 1 lists the terminal assignments for the signals of each
channel.
All of the COM terminals are connected internally and all of the
VSUP terminals are connected internally. NI does not recommend
using the VSUP and COM terminals with the cFP-RLY-421.
Table 1. Terminal Assignments
Channel
Terminal Numbers
NO IC
012
134
256
378
4 9 10
511 12
613 14
715 16
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cFP-RLY-421 4 ni.com
Caution Cascading power between two modules defeats
isolation between those modules. Cascading power from
the network module defeats all isolation between
modules in the FieldPoint bank.
Connecting Loads to the cFP-RLY-421
Wire an external power supply to the load and the IC terminal of
the individual channel as shown in Figure 2. Install a 1.5 A, 250 V
maximum, fast-acting fuse suitable for the load at the IC terminal
to protect the module and the load from damage.
Figure 2. Connecting a Load
The cFP-RLY-421 has eight SPST electromechanical relays. The
power-up state is off (open) to ensure safe installation. In the ON
Table 2. VSUP and COM Terminal Assignments
VSUP COM
17 18
19 20
21 22
23 24
25 26
27 28
29 30
31 32
+
–
To next channel
cFP-RLY-421
IC
NO
V C
VSUP
COM
or
AC
Sourcing
Load
1.5 A,
250 V max
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© National Instruments Corp. 5 cFP-RLY-421
state, the NO and IC contacts connect to form a short circuit. In the
ON state, there is an effective resistance of up to 150 mΩbetween
the NO and IC terminals, which causes a voltage drop.1For
example, if the current is 1.5 A, the voltage drop across the NO
and IC terminals can be as high as 0.225 V.
The amount of current the relay can switch depends on the voltage,
the type of load, and the ambient temperature. Refer to the
Specifications section for more information.
Protecting Contacts for Inductive Loads
When an inductive load is connected to a relay, the energy stored
in the inductive load can produce a large counter-electromotive
force when the relay switches. This flyback voltage can severely
damage the relay contacts and greatly shorten the life of the relay.
It is best to limit flyback voltages by installing a flyback diode
across an inductive DC load or a metal oxide varistor (MOV)
across an inductive AC load.
The cFP-RLY-421 has internal protection MOVs to prevent
excessively high voltage from being applied across the contacts.
The MOVs are located between the NO and IC contacts of each
relay. However, National Instruments recommends installing
protection circuits across inductive loads. The flyback protection
causes a small leakage current, which is detailed in the
Specifications section.
Refer to the NI Switches Help for information about selecting and
installing contact protection circuits. Go to ni.com/manuals,
search for switches help, and select the current version of the
NI Switches Help.
Status Indicators
After you install the cFP-RLY-421 onto a backplane and apply
power to the network module, the green POWER indicator lights
and the cFP-RLY-421 informs the network module of its presence.
When the network module recognizes the cFP-RLY-421, it sends
initial configuration information to the cFP-RLY-421. After the
cFP-RLY-421 receives this initial information, the green READY
indicator lights and the module is in normal operating mode.
1 At the end of relay life, the path resistance rises rapidly above 1 Ω.
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In addition to the green POWER and READY indicators, each
channel has a numbered, green output state indicator that lights
when the channel is in the ON state.
Isolation and Safety Guidelines
Caution Read the following information before
attempting to connect the cFP-RLY-421 to any circuits
that may contain hazardous voltages.
This section describes the isolation of the cFP-RLY-421 and its
compliance with international safety standards. The field wiring
connections are isolated from the backplane and the inter-module
communication bus. The isolation barriers in the module provide
250 Vrms Measurement Category II continuous isolation, verified
by 2,300 Vrms, 5 s dielectric withstand test. The cFP-RLY-421
provides double insulation (compliant with IEC 61010-1) for
working voltages of 250 Vrms1. Safety standards (such as those
published by UL and IEC) require the use of double insulation
between hazardous voltages and any human-accessible parts or
circuits.
Never try to use any isolation product between human-accessible
parts (such as DIN rails or monitoring stations) and circuits that
can be at hazardous potentials under normal conditions, unless the
product is specifically designed for such an application, as is the
cFP-RLY-421.
Even though the cFP-RLY-421 is designed to handle applications
with hazardous potentials, follow these guidelines to ensure a safe
system:
• As with any hazardous voltage wiring, make sure that all
wiring and connections meet applicable electrical codes and
commonsense practices. Mount terminal bases and backplanes
in an area, position, or cabinet that prevents accidental or
unauthorized access to wiring that carries hazardous voltages.
•Donot use the cFP-RLY-421 as the only isolating barrier
between human contact and working voltages higher than
250 Vrms .
1 Working voltage is defined as the signal voltage plus the common-mode voltage.
Common-mode voltage is the voltage of the module with respect to ground.
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© National Instruments Corp. 7 cFP-RLY-421
• When hazardous voltages are present on any channel, all
channels must be considered hazardous. Ensure that external
wiring and all circuits connected to the device are properly
insulated from human contact.
• Operate the cFP-RLY-421 only at or below Pollution Degree 2.
Pollution Degree 2 means that only nonconductive pollution
occurs in most cases. Occasionally, however, condensation can
cause temporary conductivity.
• You must connect the protective earth (PE) ground terminal on
the cFP-BP-xbackplane to the system safety ground. The
backplane PE ground terminal has the following symbol
stamped beside it: . Connect the backplane PE ground
terminal to the system safety ground using 14 AWG (1.6 mm)
wire with a ring lug. Use the 5/16 in. panhead screw shipped
with the backplane to secure the ring lug to the backplane PE
ground terminal.
• The cFP-RLY-421 is a UL Recognized component. The entire
Compact FieldPoint system must be installed in a UL Listed,
suitably rated NEMA or IP enclosure for safe use.
Figure 3. Installing the Compact FieldPoint System in an Enclosure
• Operate the cFP-RLY-421 at or below Measurement
Category II. Measurement Category II is for measurements
performed on circuits directly connected to the low-voltage
installation. This category refers to local-level distribution,
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such as that provided by a standard wall outlet. Do not use this
module with voltages in Measurement Categories III or IV.
Using This Product Safely
in Hazardous Locations
This product is suitable for use in U.S. and Canada: Class I,
Division 2, Groups A, B, C, D, T4 hazardous locations; and
nonhazardous locations.
Cautions Explosion hazard—Substitution of
components may impair suitability for Class I,
Division 2.
Explosion hazard—Do not disconnect equipment unless
power has been switched off or the area is known to be
nonhazardous.
Equipment must be used within its electrical and
environmental ratings. Refer to the Specifications section.
Refer to the product label for manufacturing location.
This product must be installed in an enclosure rated at least
IP 54.
Specifications
The following specifications are typical for a range of –40 to 55 °C
unless otherwise noted. All specifications are subject to change
without notice.
Relay Characteristics
Number of channels .......................... 8
Relay type ......................................... SPST, nonlatching,
normally open
Maximum switching capacity per channel (resistive load)
At 250 VAC ................................ 1.5 A at –40 to 45 °C
1.0 A at 45 to 55 °C
At 40 VDC ................................. 1.5 A at –40 to 45 °C
1.0 A at 45 to 55 °C
At 60 VDC ................................. 1.0 A
At 120 VDC ............................... 0.4 A
Minimum switching load.................. 10 mA at 5 VDC
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© National Instruments Corp. 9 cFP-RLY-421
Maximum switching power
AC .............................................. 375 VA
DC .............................................. 60 W
DC path resistance
Initial .......................................... 150 mΩ
End of life................................... ≥1 Ω
Note DC path resistance typically remains low for
the life of the relay. At the end of relay life, the path
resistance rises rapidly above 1 Ω. Load ratings apply
to relays used within the specification before the end of
relay life.
Off-state leakage
At 250 VAC ................................ 8 µA
At 120 VDC ............................... 0.12 µA
Expected life
Mechanical ................................. 2 ×107operations min
Electrical..................................... 100,000 operations
Maximum switching frequency
Mechanical ................................. 20 operations per second
Electrical..................................... 1 operation per second at
maximum load
Relay operate time ............................ 8 ms
Relay release time............................. 4 ms
Relay bounce time ............................ 4 ms
Contact material................................ Gold-plated silver
cadmium oxide
Physical
Indicators .......................................... Green POWER and
READY indicators, 8 green
output state indicators
Weight............................................... 137 g (4.8 oz)
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