GE Industrial Solutions CP2000DC54-PE - Manual (Page 12)

GE
Data Sheet
CP2000DC54-PE series dc-dc converter
Input: -40Vdc to -72Vdc; Outputs: ±54Vdc @ 2000W; 5Vdc @ 4W
August 20, 2013
©2013 General Electric Company. All rights reserved. Page 12
State Change Definition
A state_change is an indication that an event has occurred
that the MASTER should be aware of. The following events
shall trigger a state_change;
 Initial power-up of the system when AC gets
turned ON . This is the indication from the rectifier
that it has been turned ON. Note that the master
needs to read the status of each power supply to
reset the system_interrupt. If the power supply is
back-biased through the 8V_INT or the 5VSTB it
will not issue an SMBALERT# when AC power is
turned back ON.
 Whenever the power supply gets hot-plugged into
a working system. This is the indicator to the
system (MASTER) that a new power supply is on
line.
 Any changes in the bit patterns of the STATUS and
ALARM registers are a STATUS change which
triggers the SMBALERT# flag. Note that a host-
issued command such as CLEAR_FAULTS will not
trigger an SMB
Hot plug procedures
Careful system control is recommended when hot plugging
a power supply into a live system. It takes about 15 seconds
for a power supply to configure its address on the bus based
on the analog voltage levels present on the backplane. If
communications are not stopped during this interval,
multiple power supplies may respond to specific instructions
because the address of the hot plugged power supply
always defaults to xxxx000 (depending on which device is
being addressed within the power supply) until the power
supply configures its address.
The recommended procedure for hot plug is the following:
The system controller should be told which power supply is
to be removed. The controller turns the service LED ON, thus
informing the installer that the identified power supply can
be removed from the system. The system controller should
then poll the module_present signal to verify when the
power supply is re-inserted. It should time out for 15
seconds after this signal is verified. At the end of the time
out all communications can resume.
Predictive Failures
Alarm warnings that do not cause a shutdown are
indicators of potential future failures of the power supply.
For example, if a thermal sensor failed, a warning is issued
but an immediate shutdown of the power supply is not
warranted.
Another example of potential predictive failure mechanisms
can be derived from information such as fan speed when
multiple fans are used in the same power supply. If the
speed of the fans varies by more than 20% from each other,
this is an indication of an impending fan wear out.
The goal is to identify problems early before a protective
shutdown would occur that would take the power supply
out of service.
External EEPROM
A 64k-bit EEPROM is provided across the I 2 C bus. This
EEPROM is used for both storing FRU_ID information and for
providing a scratchpad memory function for customer use.
Functionally the EEPROM is equivalent to the ST M34D64
part that has its memory partitioned into a write protected
upper ¼ of memory space and the lower ¾ section that
cannot be protected. FRU_ID is written into the write
protected portion of memory.
Write protect feature: Writing into the upper 1/4 of
memory can be accomplished either by hardware or
software.
The power supply pulls down the write_protect (Wp) pin to
ground via a 500Ω resistor between the ‘module_present’
signal pin and Logic_GRD (see the Module Present Signal
section of Input Signals). Writing into the upper ¼ of
memory can be accomplished by pulling HI the
module_present pin.
An alternative, and the recommended approach, is to issue
the Enable_write command via software.
Page implementation: The external EEPROM is partitioned
into 32 byte pages. For a write operation only the starting
address is required. The device automatically increments
the memory address for each byte of additional data it
receives. However, if the 32 byte limit is exceeded the
device executes a wrap-around that will start rewriting from
the first address specified. Thus byte 33 will replace the first
byte written, byte 34 the second byte and so on. One needs
to be careful therefore not to exceed the 32 byte page
limitation of the device.