Transistor output transient pulses – Rockwell Automation 1769-BOOLEAN Compact I/O BOOLEAN Module Installation Instructions User Manual

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Publication 1769-IN077A-EN-P - May 2006

Transistor Output Transient Pulses

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.

Figure 3 illustrates that the duration of the transient is proportional to the load current.
Therefore, as the on-state load current increases, the transient pulse decreases. Transients
when you cycle power do not exceed the time duration shown for the amount of loading
indicated at 60 °C (140 °F).

Figure 3 Transient Pulse Duration as a Function of Load Current

ATTENTION

A transient pulse occurs in transistor outputs when the external dc supply
voltage is applied to the output common terminals, for example, via the
master control relay. The sudden application of voltage creates this
transient pulse. This condition is inherent in transistor outputs and is
common to solid-state devices. A transient pulse can occur regardless of
the controller having power. Refer to your controller’s user manual to
reduce inadvertent operation.

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