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Title: | DEChub/HUBwatch/PROBEwatch CONFERENCE |
Notice: | Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7 |
Moderator: | NETCAD::COLELLA DT |
|
Created: | Wed Nov 13 1991 |
Last Modified: | Fri Jun 06 1997 |
Last Successful Update: | Fri Jun 06 1997 |
Number of topics: | 4455 |
Total number of notes: | 16761 |
640.0. "DEChub900 Power Management" by QUIVER::SLAWRENCE () Wed Jan 19 1994 20:31
[I didn't write this, I'm just posting it here - SL]
If you have questions about any of the following, it might be better if
you posted a new note; we'll put follow-ups here for changes or
clarifications. - SL
===================================================================
DecHub900MS Power Management
----------------------------
Overview/Background
-------------------
This is a informational document on how power is managed in a DecHub900, from
the perspective of the Management Agent FW.
To be backwards compatible with the DecHub90, MIN modules are automatically
powered up when inserted into a DecHub900, without the intervention of the
power manager. MAX modules on the other hand, are not enabled (powered
on) when inserted into a DecHub900.
Power management is required on the DecHub900 primarily to prevent MAX
modules from being enabled (powered on) when there is not enough power
available to give. Power management also safeguards the total system should
power supplies fail (no battery backup feature).
Equations
---------
DecHub Power Supplies:
A power supply has 3 operational LIMITS (RATING) :
. how much 5v power can be supplied.
. how much 15v power can be supplied.
. how much total power can be supplied.
where, (5v power) + (15v power) DOES NOT EQUAL (total power)
and, any ONE of these limitations when reached, will cause
MAX modules to be powered down!
* A maximum of 4 power supplies can be installed onto the DecHub900.
Currently, only the DecHub900 140W power supplies are available. Due
to their low efficiency rate (AC->DC) on the DecHub900 140W power
supplies, a MAXIMUM of 420w (3 supplies) can be made available for
comsumption even when 4 supplies are installed onto the DecHub900. As
a result, the DecHub900 with 4 power supplies will ALWAYS have N+1
redundancy and a available supply of 420W power.
12v Usage:
The 12v power from the DecHub900 backplane is really from a
15v power source. The 12v power is rectified (voltage regulator
circuit) from the 15v power source on the DecHub900 backplane.
To calculate 15v power from 12v power (vice versa):
wattage (work done) / voltage (potential) = current (rate)
Xwatts = 12Volts * YAmps ---> Zwatts = 15Volts * YAmps
where, Xwatts < Zwatts
Algorithm
---------
Priority Scheme :
- Power allocation is performed starting with slot8 down to slot1.
- ALL MIN modules within the DecHub900 are given FIRST consideration
for power since they are automatically powered up.
- If a MAX module cannot be powered up, ALL MAX modules following
that one, are prevented from being powered up EVEN if any of those
MAX modules could have been. This provides predictability and
consistency of the total system.
ie: slot1,slot3,slot5 has MAX modules in them.
Cannot supply power to slot5, so slot3, slot1
are powered on or not turned on even if slot3
and/or slot1 uses much less power than slot5.
- Powering down of MAX modules starts with slot1 up to slot8 when
the total system power availability drops below 0watts.
Defaults Given :
- All MIN modules upon insertion are automatically assumed to be
consuming 7w of 5v and 0w of 15v. When a MIN module is operational,
the ACTUAL consumption numbers are determined by the power manager,
via a lookup table.
- All MAX modules upon granted power to be enabled, automatically
receives 7.5w of 15v for their 2 fans. Additional 15v power is
requested through power arbitration with the power manager and
the MAX module.
Functionality :
- The priority scheme is performed whenever:
. DecHub900 is powered up or reset.
. A hub module is inserted or removed.
. A hub modules' power requirements has been changed
(power arbitration).
. A power supply is inserted or removed.
. A power supply: good->bad, bad->good, on->off, off->on
- If a any hub module goes to temp red, or shuts itself off, the
power manager will exclude that module from future priority scheme
calculations. If that same hub module drops back to temp yellow,
then it is included in future priority scheme calculations.
- If any hub module (MAX or MIN) is removed from the DecHub900 and
WAS utilizing power, the power manager will attempt to power up
other MAX modules that were not enabled previously using the
priority scheme.
- FOR MAX MODULES: How the power manager determines the modules power
requirements.
. When a MAX module is in the DecHub900, the power manager
will determine if it is a MIN or a MAX module. This is
performed by reading the power CSRs on the DecHub900
backplane (0xFF mean MIN, otherwise MAX). This value also
identifies the 5v power requirements. The 5v power
requirements is the minimum amount of which the module can
be enabled (power up). Enabling of a MAX module in terms
of the power managers point of view, is the following check:
(total available power) >= (the 5v power + 7.5w of 15v)
Once the MAX module is "up", the power manager will request
the modules' FULL 15v requirements. This is called power
arbitration. Once the FULL 15v requirements have been
received, this value becomes the REAL power requirements of
that module and the power manager replaces this new value
with the old value for the module and then a re-calculation
of who should be "up" and who should be "down" using the
priority scheme is again performed. So, on the MAX modules'
perspective, it is either ALL power granted or NO power
granted.
N+1 Redundancy :
TERM: N+1 redundancy is accomplished when it is possible to remove
(logically) 1 power supply from the system such that it does
not affect the hub modules' current power usages. This is to
maintain system power integrity should any power supply fails.
- N+1 is attempted whenever:
. Hub is powered on or reset.
. A power supply has been inserted or removed.
. A power supply: bad->good, off->on
. 1 or more hub modules has been removed.
- N+1 loss is checked whenever:
. A power supply is removed.
. A power supply: good->bad, on->off.
. 1 or more hub modules has been inserted.
DecHub Module Power Specifications
----------------------------------
MIN MODULE TYPE Power Consumption (Watts)
5v 12v (15v Conversion)
----------------- ---- --- ----------------
ANY_OTHERS_NOT_KNOWN 7.0 0.0 <- default values first given
DEChub900 Module 15.0 0.0 0.00
DECbridge_90 7.0 9.0 11.25
DECbridge 90FL 7.0 9.0 11.25
DECrepeater 90T 7.0 0.0 0.00
10BaseT 96JAM 7.0 0.0 0.00
DECrepeater 90C 7.0 0.0 0.00
10Base2 96 JAM 7.0 0.0 0.00
DECrepeater_90FL 7.0 9.0 11.25
AUI ports 96 bit 7.0 9.0 11.25
AUI ports 128bit 7.0 9.0 11.25
DECrepeater 90FA 7.0 6.0 7.50
AUI/Fiber 96 bit 7.0 6.0 7.50
DECagent 90 7.0 6.0 7.50
DECserver 90TL 7.0 0.0 0.00
DECwanrouter 90 7.0 0.0 0.00
DECbrouter 90T2 7.0 9.0 11.25
DECbrouter 90T2A 7.0 9.0 11.25
DECbrouter 90T1 7.0 9.0 11.25
DECserver 90TL 7.0 0.0 0.00
DECserver 90M 7.0 0.0 0.00
DECserver 90L 7.0 0.0 0.00
DECserver_90Lplus 7.0 0.0 0.00
DECserver_90Lplus 7.0 0.0 0.00
DECmau 900TL 4.4 0.0 0.00
DECrepeater 900TL 6.0 0.0 0.00
DECagent 900RA 6.0 0.0 0.00
DECmau 900TC 6.0 0.0 0.00
DECrepeater 900FL 6.0 0.0 0.00
DECrepeater 900SL 6.0 0.0 0.00
(OTHERS????)
MAX MODULE TYPE Power Consumption (Watts)
5v 15v (default) 15v total w/arbitration
----------------- ---- ---- ------------------------
DETMM 20.0 7.50 8.250
DEFMM 40.0 7.50 8.250
DETTM 20.0 7.50 15.000
DETMI 7.5 7.50 ?????
DSRVZ 20.0 7.50 ?????
DEF6X 40.0 7.50 8.250
DEFBA 50.0 7.50 30.000
DEBMP 40.0 7.50 30.000
(OTHERS????)
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