Universal AC sequencer for a server

Details Universal AC sequencer for a server Universal AC sequencer for a server

2001-07-26

2003-02-25

Paladini, Albert W. (Department: 2827)

Electrical transmission or interconnection systems

Plural load circuit systems

Selectively connected or controlled load circuits

C700S286000, C710S118000, C710S100000, C710S110000, C307S038000, C713S321000

Reissue Patent

active

RE038004

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to AC sequencers that are used to power-up computer network servers, and more specifically to providing such sequencers that meet domestic and foreign power cord and connector specifications, and that can provide a daisy-chain function with status information as to another sequencer slaved to a first sequencer.
BACKGROUND OF THE INVENTION
Networks are electronic systems that include server stations that couple information to one or more client/slave stations. When a server is first turned on, e.g., when electrical power is first applied, it is important to first power server units such as the central processing system (“CPU”), often referred to as a “card cage”, and then provide power to ancillary systems, including memory units. It is the function of an AC sequencer to ensure that server power-up applies power to server units in a correct sequence. For example, if power were simultaneously and instantly applied to all units within the server, the in-rush of current would almost certainly trip circuit breakers associated with the source of AC power into the sequencer.
FIG. 1A
shows a prior art network system
10
such as might be used in the United States. System
10
includes a server
20
and a client/slave
30
, each of which is mounted in a cabinet or relay-type rack
40
. Rack
40
commonly measures perhaps 142 cm in height, and about 56 cm in width and depth. Source AC power to units
20
and
30
is received via a power cord
50
whose free end is connected to an AC connector
60
sized to fit into an AC wall outlet receptacle
70
. As well be described, the other end of power cord
50
is hardwired to an AC sequencer unit
80
within rack
40
. Typically source AC power is about 210 VAC to 240 VAC, 52 Hz to 60 Hz, 30 A maximum.
Each unit
20
,
30
includes an AC sequencer
80
that receives source AC via hardwired power cord
50
, and sequentially provides AC operating power to other units within unit
20
or unit
30
. Because unit
20
is a server unit
20
, it will include a central processing unit card (“CPU”)
90
, which card is not present in slave unit
30
. As shown in
FIG. 1A
, present in unit
20
and slave unit
30
are a fan tray
100
for cooling the unit, and storage or memory trays, shown as
110
A,
110
B,
110
C. etc. The storage units may include perhaps six hard disk drive assemblies, compact disk (“CD”) assemblies, optical disk assemblies, and magnetic tape drives. Client/slave unit
40
is shown with a further memory unit, memory tray
110
C, that has been plugged into cabinet
30
in lieu of a CPU card tray
80
. In this fashion, unit
30
is able to provide additional storage capability by allowing three rather than two trays for memory assemblies.
If AC operating power were simultaneously provided to unit
20
and unit
30
at power-up, the resultant current surge could exceed the current limit of protective circuit breakers within each AC sequencer unit. Further, simultaneous receipt of AC operating power by CPU tray
90
and various associated memory trays, e.g.,
110
A,
110
B, could result in inoperative starting states for the master unit
20
. Thus, a function of AC sequencer
80
is to receive raw AC power from wall socket
70
, and to sequentially provide operating power to other units within the same rack
40
.
More specifically, each AC sequence
80
typically outputs AC operating voltage to three power output ports.
A first outlet port
120
provides the “unswitched” AC voltage as soon as operating voltage is coupled to the AC sequencer. A second outlet port
130
provides a “switched 1” AC voltage, which is defined as a voltage which is applied only after application of a POWER-ON switch closure control signal to port
135
-IN. A third outlet port
140
provides a “switched 2” AC voltage which is defined as a voltage which is applied only after a delay time of about four to six seconds from occurrence of the “switched 1” AC power.
The connection between each AC sequencer
80
and control input port
135
-IN is hardwired to the AC sequencer. Further, each AC sequencer outputs control signals through an output control port
135
-OUT. These control signals may be coupled via a cable
155
to the input control port
135
-IN of another unit
30
, as shown in FIG.
1
A.
System
10
in
FIG. 1A
is intended for use in the United States. As such, wall connector
70
, AC connector plug
60
and power cord
50
(among other components) must satisfy Underwriter Laboratories (“UL”) standards that apply to electrical equipment used in the United States. For example, the diameter and number of wires within the power cord
50
and the dimensions and configuration of the AC connector plug
60
will be governed by applicable UL standards.
However, electrical power standards differ from country to country. Thus, although two network systems, servers and client/slaves are commonly used world-wide, manufacturers of AC sequencers have had to manufacture different sequencer versions for different countries. For example,
FIG. 1B
depicts a system
10
′ such as might be used in Europe or in another country whose electrical power standards do not conform to UL standards.
Among other changes, wall-mounted AC outlet receptacle
70
′ will have a different configuration than a U.L. approved receptacle
70
. Because applicable standards differ, AC plug
60
′, and AC power cord
50
′ will be different, and AC connector
60
′, and indeed sequencer
80
′ must thus be changed for system
10
′ from what was manufactured for system
10
.
Unfortunately, standards applicable in various foreign countries preclude providing AC sequencer
80
′ with multiple AC power cords
50
′ and AC connector
60
′. Such standards also preclude providing differently shaped connectors on the AC sequencer, into one of which a suitable AC power cord could be plugged, rather than hard-wire the AC power cord to the AC sequencer. The other end of such an AC power cord could otherwise have attached an AC connector plug appropriate for the country in which the sequencer was to be used.
The inability of prior art AC sequencers
80
,
80
′ to conform to applicable electrical power and connector standards in all major countries adds to the manufacturing cost that a “family” of sequencers must be produced. Stated differently, if a single AC sequencer could be designed for use world-wide, the cost to produce and indeed maintain the sequencer would be reduced.
Prior art AC sequencers such as shown in
FIGS. 1A and 1B
suffer an additional deficiency in that often there is a need for more resources than can be supported in a single cabinet rack
40
. For example, server
20
may require more storage capacity than can be accommodated using only memory trays
110
A,
110
B, yet there are no additional tray spaces to receive additional memory. One solution might be to daisy-chain server
20
with a slave
30
using cable
155
and associated connectors. This might provide server
20
with more resources, for example, three additional trays of memory within cabinet
30
. In such an application, unit
30
would not be a client per se, but rather a slave that provides additional resources to master unit
20
.
Unfortunately, such daisy-chaining is not readily implemented using prior art AC sequencers because there is not a universally accepted connector for the control input/output signals
135
-IN,
135
-OUT. A second impediment to such daisy-chaining is that the control signals presented at
135
-IN could only be switch openings or closures (e.g., a 0 &OHgr; or ∞&OHgr; condition). If the control could also accept voltage or current source signals, it would be possible to couple slave sequencers to master sequencers such that full control and status information with respect to the slave unit was available at the server unit.
Thus, there is a need for an AC sequencer to which AC operating power may be coupled in a universal fashion such that a common AC sequencer complies with applicable po

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