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4
Chapter 4 Features and Functions
Digital I/O Operation
Digital Input Operation
•
From the front-panel, you can read data from the built-in digital I/O
bits/port (numbered 090 through 094) or any one of the 8-bit ports on
a digital I/O module or multifunction module.
•
From the remote interface, you can read data from the individual bit
channels and 8-, 16-, or 32-bit ports on a digital I/O module or
multifunction module, as well as from the built-in digital I/O bits/port
(numbered 090 through 094).
•
Instrument reset will set all digital I/O ports in the instrument as
input ports. Pressing Card Reset or issuing a RESET command will
set all ports on the specified module as input ports (ports on other
modules are not affected).
•
Front-Panel Operation: Select an 8-bit digital I/O port, press Read to
read the data from the port. The data can be displayed as either
decimal or binary (see page 33).
•
Remote Interface Operation: Use the following command to read an
individual bit (bit 6) on a module in slot 4. A "0" (bit cleared) or a "1"
(bit set) will be returned.
OUTPUT 709; "DREAD 402"
OUTPUT 709; "VIEW 403"
The range of possible returned values is shown:
Parameter
Decimal Range
BYTE
WORD
-32768 to 32767
LWORD
-2
WORD values greater then 32767 and LWORD values greater then
31
for (2
-1) are returned as negative numbers. These values are in 2's
complement form.
92
! Read data from Port 402.
! View a bit channel 4.
0 to 255
31
31
-80000000
to (2
-1)
Hex range
00
to FF
h
h
-8000
to 7FFF
h
h
to 7FFFFFFF
h
h
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