Rockwell Automation 1747-L40 SLC 500 Fixed Hardware Style - Manual (Page 36)

Chapter 1
Selecting Your Hardware Components
1–17
Transistor Output Transient Pulses
This section applies to the following SLC 500 Fixed I/O processors and
SLC 500 I/O modules that have transistor outputs.
Fixed I/O Processors I/O Modules
1747-L20E 1746-OB8
1747-L20G 1746-OV8
1747-L20L 1746-OB16
1747-L20N 1746-OBP16
1747-L30L 1746-OV16
1747-L40E 1746-OB32
1747-L40L 1746-OV32
For the SLC 500 products listed above, the maximum duration of the
transient pulse occurs when minimum load is connected to the output.
However, for most applications the energy of the transient pulse is not
sufficient to energize the load.
ATTENTION: A transient pulse occurs in transistor outputs
when the external DC supply voltage is applied to the common
output terminals (e.g., via the master control relay). The sudden
application of voltage creates this transient pulse. (See the
following graph.) This condition is inherent in transistor outputs
and is common to solid state devices. A transient pulse can occur
regardless of the processor having power or not.
!
Duration of Transient (T)
Transient (I)
(On-State Load Current)
Current
Time