Browse Prior Art Database

Software Technique to Call for the Cleaning of Air Filters by Monitoring Power On Hours

IP.com Disclosure Number: IPCOM000108842D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 2 page(s) / 98K

Publishing Venue

IBM

Related People

Galinis, EI: AUTHOR [+3]

Abstract

This article describes a technique to use non-volatile memory in point- of-sale terminals and software to implement a resettable air filter Power-On-Hours monitor and filter-cleaning reminder.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Software Technique to Call for the Cleaning of Air Filters by Monitoring Power On Hours

       This article describes a technique to use non-volatile
memory in point- of-sale terminals and software to implement a
resettable air filter Power-On-Hours monitor and filter-cleaning
reminder.

      In a point-of-sale terminal containing a single air filter
which requires periodic removal and cleaning, failure to clean the
filter eventually results in decreased air flow through the machine,
higher operating temperatures and, in severe cases, thermal shutdown
of the power supply.  The technique disclosed herein permits software
to monitor the level of contamination of the air filter and provides
reminders to machine operators when it is time to clean or replace
the filter.

      Some terminals contain a minimum of 32K (expandable to 64K) of
battery-backed static RAM (BBSRAM), which is memory kept refreshed
when the machine is powered off by a battery within the system (and
hence non-volatile).  The system power-on-self test (POST) performs
an operation called 'ROM scan,' during which the POST software scans
through the memory address space of the processor looking for ROM
memory on adapter cards installed in the system.

      Normally, the BBSRAM is outside of the range of addresses
included in the ROM scan, but by changing a bit in a configuration
byte stored in BBSRAM, programs can be loaded in BBSRAM and included
in the ROM scan where they will get control during POST.

      If a program is placed in BBSRAM which uses a periodic
interrupt to time the power-on-hours of the system and if the program
attempts to notify the terminal operator when a predetermined limit
is reached and if a mechanism for resetting the hours count is
provided, then this program can serve as a reminder to the machine
operator that the filters need cleaning.

      The following describes a prototype program called FILTMON.EXE
which implements an air filter monitor using BBSRAM and POST ROM
scan.

      When FILTMON is executed, it copies a portion of itself into
BBSRAM and then instructs the operator to reboot the machine.
Installing the program in BBSRAM involves the steps of removing the
write-protection from the BBSRAM, setting the configuration option
bit that allo...