777810-01 Datasheet, PDF (1/9 Pages) National Instruments Corporation – 48-Bit Isolated Digital I/O

48-Bit Isolated Digital I/O
NI 6527
• 24 optically isolated digital inputs
(0-28 VDC)
• 24 isolated, solid-state relay digital
outputs (0-60 VDC, 0-30 V_rms)
• Switch up to 120 mA
• Digital filtering on inputs
• Messaging (change notification)
• NI-DAQ driver simplifies
configuration and measurements
Models
• NI PCI-6527
• NI PXI-6527
Operating Systems
• Windows 2000/NT/XP
• Real-time performance with
LabVIEW (page 134)
• Others such as Linux and
Mac OS X (page 187)
Recommended Software
• LabVIEW
• LabWindows/CVI
• Measurement Studio
Other Compatible Software
• Visual Basic
• C/C++, C#
Driver Software (included)
• NI-DAQ 7
Family
Bus
NI 6527
PCI,
PXI
Digital I/O Lines
24 inputs and
24 outputs
Maximum Rate
Software timed
Logic Level
O to 28 VDC input
and 0 to 60 VDC
(30 V_rms) output
Isolation
60 VDC
channel to channel
Table 1. Digital I/O Products Specifications Summary (See page 385 for detailed specifications.)
Handshaking I/O
–
8255 chipset
–
Change Notification Pattern Matching
✓
–
Overview and Applications
NI 6527 devices are 48-bit, parallel, isolated DIO interfaces for PCI
and PXI. They have 24 optically isolated digital inputs and 24 solid-
state relay outputs. NI 6527 devices can sense digital levels up to
28 VDC and switch currents up to 120 mA. The channel-to-channel
isolated inputs and outputs protect your system, reduce noise, and
break ground loops.
Features
Digital Inputs
You can use the 24 optically isolated inputs of the NI 6527 devices to
read the status of external logic at TTL and non-TTL levels.
Each input channel has two differential isolated terminals – one for
the signal and one for its reference. A potential difference of 2 to 28
VDC between the two terminals registers as a logic high. Logic low is
between 0 and 1 V. The inputs feature 60 VDC isolation from the
computer and between channels.
Messaging – Change Notification
NI 6527 devices can generate a message when one or more user-
selected input lines changes, either from low to high, high to low, or
both. Once notified of a change, NI-DAQ can read the status of other
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.
Debouncing Filter for Glitch Removal
Each input line can be digitally filtered to prevent a momentary glitch
or spike from affecting the line state. When you use messaging, filtering
blocks spurious change events caused by noise on the input line.
Digital Switch Outputs and Power-Up States
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
closes the connection between the terminals; writing a logic high
opens the connection. Depending on how your load connects to the
terminals, an output can either source or sink currents. By adding
pull-up resistors externally and, if needed, an isolated power supply,
you can output digital signals that source or sink currents. The solid-
state relay outputs have a maximum switching capacity of 60 VDC,
30 V_rms, or 120 mA, and are isolated up to 60 VDC or 30 V_rms from
the computer and between channels.
NI 6527 device outputs include circuitry to protect against
transient currents above the rated values. When excessive current
flows through the relay, the relay limits the current to approximately
260 mA (typical).
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