MediaMatrix PCU 2100 Manual - page 10
Page 10
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PCU 2100 Integrator’s Manual
Protection
The PCU 2100 includes integral supervisory and protection features designed to provide seamless,
stable operation. Each power supply output circuit is protected by a self-resetting fuse. In case of
an overload or short, the circuit will shut down until the condition is removed. For the bi-polar sup-
plies, the positive and negative outputs are supervised in tandem. An overload on either supply will
activate a crowbar circuit that will terminate both legs of the supply for the circuit. If this should
occur, the line input voltage must be cycled with sufficient OFF time to reset the protection circuitry.
This can be done either by unplugging the line cord or by removing the line fuses.
In addition, the primary DC supply circuits are protected to prevent the transformers from a cumula-
tive overload. Front panel monitoring indicates the status of the main supply. There is a green LED
for each leg of the supply for each bank. Status LEDs indicate the health of the +15VDC, -15VDC
and +12VDC supply circuits. Under normal operation, these LEDs will illuminate (green). Under a
fault condition these LEDs will NOT be illuminated.
Additional protection is provided for each bank at the primary AC line input. Each bank of the AC line
input is fused independently for each transformer. If one fails, the other supply will still function.
Supervision
The PCU 2100 includes a supervisory system with integral Fault Status monitoring. Each bank
includes a front-panel Fault LED and corresponding rear-panel Fault Relay contacts. This supervisory
system will provide an alarm for failure of any of the following circuits:
• AC Mains Line Power
• Main DC Secondary Circuits
• 15V DC Output Circuits (+15V, -15V)
• 12V DC Output Circuits
The supervisory system provides constant monitoring of each circuit. If a fault condition on any of
these circuits is detected, the supervisory system activates an internal Form-C relay. The relay con-
tacts are provided at the rear panel and include normally-open (N.O.) and normally-closed (N.C.)
contacts. The contacts are rated for low current applications and are used for signaling purposes
only. Usually, these contacts are connected to external equipment to translate an alarm condition to
the MediaMatrix audio processing system or third party equipment.
NOTE: These contacts are not designed to switch AC power line voltages.
In addition to the rear panel contacts, a front panel Fault LED is provided to indicate relay status. If
the Fault relay is engaged, the Fault LED will illuminate in red. Under normal operation, the Fault
LED will not be illuminated.
It should be noted that the behavior of the Fault Status system is dependent on the Fault Condition.
If an overload is detected on any circuit, the Fault LEDs will be red and the relay will be engaged. If
there is a total power loss, the LEDs will NOT be illuminated, but the relay will engage to fault status.
Under normal operation, the relay is always energized. A loss of power will disengage the relay natu-
rally, providing a method for externalizing a general failure alarm. This type of supervision enables
the designer to configure alarms for any abnormal condition, regardless of the failure mode.