Low-Cost Industrial Digital I/O – 150 V
NI 6521
• 8, ±30 VDC digital inputs with 60 V
channel-to-channel isolation
• 8 nonlatching mechanical relay outputs
• 150 V AC/DC maximum switching voltage
with maximum switching current of 2 A
and maximum switching power of 60 W
• UL listed: UL 61010-1 (IEC 61010-1)
• High-reliability industrial feature set
includes isolation, programmable
power-up states, digital filtering,
watchdog timers, and change detection
• NI measurement services software for
highest productivity and performance
Recommended Software
• LabVIEW
• LabWindows/CVI
• Measurement Studio
Other Compatible Software
• C, C++
• Microsoft Visual Studio .NET 2003
Measurement Services
Software (included)
• NI-DAQmx driver, Version 7.5 or later
Safety
Operating Systems
• Windows 2000/NT/XP
• LabVIEW Real-Time
INPUT
Product
NI 6521
Bus
PCI, PXI
Inputs
8
Isolation
60 V channel-to-channel
Low
Threshold
±4 VDC
High
Threshold
±11 VDC
Mechanical
Relay Outputs
8
OUTPUT
Max Voltage
150 V AC/DC
Max Current
2A
Max Power
60 W
Industrial
Feature Set
Overview and Applications
The National Instruments 6521 products are industrial digital I/O devices
with eight channel-to-channel isolated digital inputs and eight nonlatching
mechanical relay outputs. You can use the eight differential, isolated,
±30 VDC digital inputs to read the status of sensors, actuators, and logic
devices. You can use the bipolar digital input channels to read from both
sinking and sourcing devices. NI 6521 devices register a logic low if the
voltage is between ±4 V, and register a logic high if the voltage is less
than -11 V or greater than +11 V.
NI 6521 devices offer three single-pole double-throw (SPDT) Form C
relays and five single-pole single-throw (SPST) Form A relays. You can
use NI 6521 relay outputs to switch devices requiring up to 150 V AC/DC.
NI 6521 relay outputs have maximum current rating of 2A and maximum
switching power of 60 W.
Note:
The switching current is limited by the maximum switching
power and maximum voltage. (current = power/voltage)
NI 6521 devices offer completely programmable configuration and do not
require setting up jumpers or DIP switches. These devices are ideal for use
with a programmable automation controller (PAC) for automotive test,
industrial monitoring, and control applications. With high-current drive, high-
voltage outputs, and isolation, you can connect the digital I/O module directly
to a wide array of industrial electronic devices, sensors, and actuators.
NI 6521 devices take advantage of NI-DAQmx measurement services
software (Version 7.5 or later) to speed up application development with
many helpful features such as DAQ Assistant, automatic code
generation, and high-performance multithreaded streaming technology.
Safety
•
•
•
•
•
UL listed: UL 61010-1 (IEC 61010-1)
Keyed connector
Insulation covers
Complete software configuration
High-voltage accessories
NI 6521 devices are UL listed and require the use of a keyed connector
to prevent high-voltage signals from accidentally being connected to a
low-voltage device. For added safety, PCI-6521 includes insulation covers
on both sides of the board to prevent the user from coming in contact
with high-voltage traces. Complete software configuration means that
the user at no point is required to come in the vicinity of high-voltage
traces. Several low-cost, high-voltage accessory options are available
to ensure safe operation.
Isolation
Channel-to-channel . . . . . . . . . . . . . . . . . . . . . . .60 VDC continuous
1
Channel-to-bus . . . . . . . . . . . . . . . . . . . . . . . . . .150 VDC continuous
2
Channel-to-earth . . . . . . . . . . . . . . . . . . . . . . . . .150 VDC continuous
3
1
2
3
Verified by 620 V
rms
dielectric withstand test, 5 s
Verified by 1400 V
rms
dielectric withstand test, 5 s
Verified by 850 V
rms
dielectric withstand test, 5 s
NI [ NATIONAL INSTRUMENTS CORPORATION ]
