48-Bit Isolated Digital I/O
NI 6527
• 24 optically isolated digital inputs
(0-28 VDC)
Operating Systems
• Windows 2000/NT/XP
• 24 isolated, solid-state relay digital
• Real-time performance with
LabVIEW (page 134)
outputs (0-60 VDC, 0-30 Vrms
)
• Switch up to 120 mA
• Digital filtering on inputs
• Others such as Linux and
Mac OS X (page 187)
• Messaging (change notification)
• NI-DAQ driver simplifies
configuration and measurements
Recommended Software
• LabVIEW
• LabWindows/CVI
• Measurement Studio
Models
• NI PCI-6527
• NI PXI-6527
Other Compatible Software
• Visual Basic
• C/C++, C#
Driver Software (included)
• NI-DAQ 7
Family
NI 6527
Bus
PCI,
PXI
Digital I/O Lines
24 inputs and
24 outputs
Maximum Rate
Software timed
Logic Level
Isolation
60 VDC
channel to channel
Handshaking I/O
8255 chipset
Change Notification
Pattern Matching
O to 28 VDC input
and 0 to 60 VDC
(30 Vrms) output
–
–
✓
–
Table 1. Digital I/O Products Specifications Summary (See page 385 for detailed specifications.)
Overview and Applications
Debouncing Filter for Glitch Removal
NI 6527 devices are 48-bit, parallel, isolated DIO interfaces for PCI Each input line can be digitally filtered to prevent a momentary glitch
and PXI. They have 24 optically isolated digital inputs and 24 solid- or spike from affecting the line state. When you use messaging, filtering
state relay outputs. NI 6527 devices can sense digital levels up to blocks spurious change events caused by noise on the input line.
28 VDC and switch currents up to 120 mA. The channel-to-channel
isolated inputs and outputs protect your system, reduce noise, and Digital Switch Outputs and Power-Up States
break ground loops.
The 24 solid-state relay outputs on the NI 6527 devices can switch
external devices, including those requiring high input currents, and
control digital logic levels at both TTL and non-TTL levels.
Each relay output has two terminals. Writing a logic low to an output
Features
Digital Inputs
You can use the 24 optically isolated inputs of the NI 6527 devices to closes the connection between the terminals; writing a logic high
read the status of external logic at TTL and non-TTL levels. opens the connection. Depending on how your load connects to the
Each input channel has two differential isolated terminals – one for terminals, an output can either source or sink currents. By adding
the signal and one for its reference. A potential difference of 2 to 28 pull-up resistors externally and, if needed, an isolated power supply,
VDC between the two terminals registers as a logic high. Logic low is you can output digital signals that source or sink currents. The solid-
between 0 and 1 V. The inputs feature 60 VDC isolation from the state relay outputs have a maximum switching capacity of 60 VDC,
computer and between channels.
30 Vrms, or 120 mA, and are isolated up to 60 VDC or 30 Vrms from
the computer and between channels.
Messaging – Change Notification
NI 6527 device outputs include circuitry to protect against
NI 6527 devices can generate a message when one or more user- transient currents above the rated values. When excessive current
selected input lines changes, either from low to high, high to low, or flows through the relay, the relay limits the current to approximately
both. Once notified of a change, NI-DAQ can read the status of other 260 mA (typical).
input lines, set outputs, or perform some other programmed
operation. Using this feature, you can monitor lines without polling,
thus using your CPU more efficiently.
National Instruments • Tel: (800) 433-3488 • Fax: (512) 683-9300 • info@ni.com • ni.com 377