Rockwell Automation SA500 DC Bus Supply - Manual (Page 12)

2-2 SA500 DC Bus Supply
2.1.1 LED Indicators
The four LEDs visible through the faceplate provide diagnostics information about the
DC bus supply. See table 2.1.
:
2.1.2 Interface Connector (TB1)
Terminals 1 and 2 or interface connector TB1 are used to indicate an overtemperature
fault detected by the internal protective circuitry of the DC bus supply. See figure 2.2.
The following signals are present on the terminals.
• Terminal 1: – status signal
• Terminal 2: + status signal
Together these terminals provide an output signal from a normally-open relay rated
24 VDC @ 0.4A, resistive load, 25° C (77° F). This signal can be monitored in an
AutoMax rack through a 24V DC input module.
• When the bus supply is not powered up, the relay’s contacts are open.
• When the bus supply is powered up and no overtemperature fault exists, the relay’s
contacts are closed.
• When the bus supply is powered up and an overtemperature fault does exist, the
relay’s contacts are open.
If an overtemperature fault exists, the pre-charge is disabled. However, it is possible
the DC bus capacitors may not discharge due to a component failure. The user should
disconnect AC input power and verify that the DC bus capacitors are discharged
before touching any internal components. See section 3.6.
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LED Name LED Color Description
PHASE LOSS Red Off: OK (normal)
ON: Loss of one phase or more of the incoming
AC power
OVERTEMP Red Off: OK (normal)
ON: The bus supply has overheated
DISABLED Red Off: The bus supply has AC input power applied
and is enabled (normal)
ON: DC bus supply is disabled (check jumper
W1, see section 2.1.1)
PSM READY Green Off: No DC bus voltage
ON: DC bus voltage is present (normal)
!
ATTENTION: DC bus capacitors retain hazardous voltages after input
power has been disconnected. After disconnecting input power from the
DC bus supply, wait five (5) minutes and then measure the voltage at the
POS and NEG terminals of the DC bus supply and each Power Module
to ensure the DC bus capacitors are discharged before touching any
internal components. Failure to observe this precaution could result in
severe bodily injury or loss of life.