Relay Modules for Compact FieldPoint
NI cFP-RLY-421, NI cFP-RLY-423
• 4 or 8 electromechanical relays
•
8 form A (SPST), RLY-421
•
4 form C (SPDT), RLY-423
• Switch 250 VAC, 120 VDC
• Switch 1.5 A, maximum
• 2,300 V
rms
bank isolation for transient
overvoltage protection
• Hot swappable with autoconfiguration
• -40 to 55 °C operating range
(cFP-RLY-421)
• -40 to 60 °C operating range
(cFP-RLY-423)
NEW
Module
cFP-RLY-421
cFP-RLY-423
Output Channels
8
4
Maximum
Output Types
120 VDC, 250 VAC
120 VDC, 250 VAC
Output Current Rating
(See Specifications)
1.5 A
1.5 A
Separate Ground
Plane
per Channel
✓
✓
Isolation
The cFP-RLY-42x modules feature optical bank isolation with
2,300 V
rms
of breakdown isolation. In addition, the modules provide
double insulation for up to 250 V
rms
of operational isolation. Compact
FieldPoint can safely be used in applications where hazardous voltages
are present with the cFP-CB-1 connector block. These Compact
FieldPoint modules do not have channel-to-channel isolation.
Overview
The National Instruments cFP-RLY-42x devices are versatile relay
modules for Compact FieldPoint that can be used to control digital
signals ranging from low voltage to 120 VDC and to 250 VAC. These
modules are commonly used to control indicator lights, motors, and
power circuits. All the modules include onboard diagnostics to ensure
trouble-free installation and maintenance. Similar relay modules are
available for FieldPoint, see page 572 for more information.
Power Requirements
Because the cFP-RLY-42x are high power consumption modules,
they could limit the number of I/O modules that you can connect to
a single network interface module. Controllers and network interface
modules supply up to 9 W to power I/O modules. The RLY-421
requires up to 2.5 W and the RLY-423 requires up to 1.5 W.
Relay Modules
NI cFP-RLY-42x modules provide built-in module-to-module
isolation to protect your Compact FieldPoint system and controller
from high voltage levels. Each channel on the RLY-42x uses
electrically isolated output relays so that each relay output has a
separate ground plane and each channel can be used with a different
voltage potential. Thus, you can connect one channel to a 24 VDC
and another channel on the same module to a 250 VAC.
All the channels on the relay modules feature LEDs that indicates the
output state of each channel. The modules all feature a maximum
switching frequency of 10 Hz (20 operations). Overall data throughput
depends on software loop speeds and network speeds.
Field I/O Connections
Each input channel on the cFP-RLY-421 has two terminals:
1. Relay common terminal (IC)
2. Normally open terminal (NO)
Each channel of the cFP-RLY-423 has three terminals:
1. Normally open terminal (NO)
2. Normally closed terminal (NC)
3. Relay common terminal (IC)
NI [ NATIONAL INSTRUMENTS CORPORATION ]
