Chapter 2
Digital I/O
2-4
ni.com
Table 2-2 summarizes the isolated inputs and outputs available on the
NI 8254R.
I/O for Normal Operation
The following sections describe I/O functions that are available on the
NI 8254R during normal operation.
Table 2-2. NI 8254R Isolated Inputs and Outputs
Primary
Function
Input or
Output
Number
Available
Signal
Names
44-Pin
D-SUB on
NI 8255R
Device Pin
Number
37-Pin
Terminal
Block
Number
Trigger
Input
3
TRIG 0
*
ISO Input 5
†
ISO Input 8
*
11
35
40
—
15
27
Quadrature
Encoder
Input
1
ISO Input 6
ISO Input 7
37
38
25
26
External
Shutdown
Control
Input
1
ISO Input 11
44
31
Product
Selection
Port
†
Input
1
ISO Input 0
ISO Input 1
ISO Input 2
ISO Input 3
ISO Input 4
15
30
31
32
34
9
10
11
13
14
General
Purpose
Input
2
ISO Input 9
*
ISO Input 10
*
41
43
29
30
General
Purpose
Output
4
ISO Output 0
ISO Output 1
ISO Output 2
ISO Output 3
12
13
27
28
198
35
36
37
* TRIG 0, ISO Input 8, ISO Input 9, and ISO Input 10 can also function as trigger change detectors.
†
ISO Input 5 can also function as a latch for the product selection port.