Chapter3 MakingSignal Connections
6527User Manual 3-6 ni.com
Power Connections
Four of the pins on the I/O connector are not isolated. Pin 50 and pin 100
connectto GND , thecomputer ground reference. Pin 49 and pin 99 of
the I/O connector supply +5 V from the computer power supply via a
self-resettingfuse. The fuse resets automatically within a few seconds after
an overcurrent condition is removed. The +5 V pins are referenced to the
GNDpins and can be used to power external digit alci rcuitry that does not
require isolation.
•Powerrating: 1 A at +4.5 to +5.25 V
Warning Thepower pins, +5 V and GND, are not isolated; they connect to your computer
powersupply. Never connect a +5 V power pin directly to GND. Never connect a +5 V or
GND pin to anyother voltage source; doing so can lead to injury.National Instruments is
not liable for anydamage or injury resulting from such a connection.
Pin Signal Name Description
83,85, 87, 89,
91, 93, 95, 97
DIG+3.<7..0> Isolated output port 3, firstterminals—Each ofthese is the first
oftwo terminals of a bidirectional solid-state relay 1.Alogiclow
(datab it of 0) closes the relay.
84,86, 88, 90,
92, 94, 96, 98
DIG–3.<7..0> Isolatedoutput port 3, second terminals —Each of these is the
second of twoter minals of a bidirectional solid-state relay.
A logic low(data bit of 0) cl oses the relay.
67,69, 71, 73,
75, 77, 79, 81
DIG+4.<7..0> Isolated output port 4, firstterminals—Each ofthese is the first
oftwo terminals of a bidi rectional solid-state relay.A logic low
(datab it of 0) closes the relay.
68,70, 72, 74,
76, 78, 80, 82
DIG–4.<7..0> Isolatedoutput port 4, second terminals —Each of these is the
second of twoter minals of a bidirectional solid-state relay.
A logic low(data bit of 0) cl oses the relay.
51,53, 55, 57,
59, 61, 63, 65
DIG+5.<7..0> Isolated output port 5, firstterminals—Each ofthese is the first
oftwo terminals of a bidi rectional solid-state relay.A logic low
(datab it of 0) closes the relay.
52,54, 56, 58,
60, 62, 64, 66
DIG–5.<7..0> Isolatedoutput port 5, second terminals —Each of these is the
second of twoter minals of a bidirectional solid-state relay.
A logic low(data bit of 0) cl oses the relay.
1Theconnection is complete when the relay is closed. The connection is broken when the relay is open.
Table3-2. Signal Descriptions for 6527 I/O Connector Pins (Continued)