Trusted High Integrity Power Supply System
1. Description
Rockwell Automation Publication PD_T8200
Issue 11
5
Figure 3 Block Diagram of a Dual dc I/O Power Supply Module
Each primary power input is individually fused and filtered with both standard line filters
and metal oxide varistors (MOVs). The filters attenuate any high frequency common mode
and normal mode noise present in the power distribution system. The MOVs clamp high
voltage transients.
Filter, rectifier, and power factor correction circuits convert primary ac input power to bulk
dc voltage. The switching regulator converts bulk dc power to regulated dc output voltage.
Sensing, status, control and timing circuits provide for the following:
•
Input power failure
- Active low status output. Indicates when the input voltage is
below 85
Vac
or 18
Vdc
. There is a separate signal for each input.
•
Bulk power failure
- Active high status output on ac input modules only. Indicates
the dc bulk voltage (power factor correction (PFC output)) is outside the specified
range. There is a separate signal for each input.
•
High temperature warning alarm
- Both an active high and active low status output
are provided. Indicates when the module temperature exceeds 75
°
C. The
temperature is sensed near the air inlet (bottom) of the module.
•
High temperature shutdown
- Internal signal that will shut down the switching
regulator if module temperature is above 85 °C. The temperature is sensed near the
air inlet (bottom) of the module.
•
Output over-voltage
- Internal signal that will shut down the switching regulator if
the output voltage e18
Vdc
for the 15 volt module and +28
Vdc
for the
24 volt module. Over-voltage protection circuitry activation is a permanent error
condition, requiring manual intervention to return module to normal operation.
Power Supply Module
DC
Output
I/P Filter & Protection
I/P Filter & Protection
PW M
Switching Regulator
T1:a
T1:b
I/P A Fail
Fail
High Tempterature
Reset
O/P Current
Status & Control
Remote Off
I/P B Fail
Status & Control
Source
A
Source
B
