Rockwell Automation 1791-XXXX Discrete I/O AC and DC Block I/O Input and Output Modules - Manual (Page 17)

I/O Interface and System Design
Chapter 2
2-7
DC Outputs
The dc output circuits for block I/O are capable of driving dc loads with a
maximum surge current (inrush) of 3A/72 Watts and a maximum holding
current of 500mA/12 Watts at 60
o C (1A/24 Watts at 30 o C). The maximum
drive characteristics are shown below (Figure 2.8).
Figure 2.8
dc Output Drive Current
3A
500mA
0
50ms
Time
Current
0
Surge
1A
Continuous @ 30 o C
Continuous @ 60 o C
The drive circuit for dc outputs is shown in Figure 2.9.
Figure 2.9
Simplified Schematic of dc Output Circuit
Output
Indication
LED
(logic)
System
Circuitry
Opto
Isolation
+10-30V dc
12247-I
Return
Output +
+
-
R
L
4K Ω
10K Ω
15V
1N4004
When sizing output loads, check the documentation supplied with the
output device for the surge and continuous current needed to operate the
device. Refer to Table 2.A to determine which Allen-Bradley products
will directly interface to the outputs.