The AP7940 from American Power Conversion (https://www.apc.com) is an older unit with limited ability to automatically read the values. I came up with a set of Perl scripts which will do this.

It is definitely a hack. The first thing you must do is set up an sftp server and tell the AP7940 to write the log files to that location (defined as $logdir in this script).

This is done asynchronously. The AP7940 ftp's the log files hourly. processPDULogs is then set up as a cron job which runs once an hour. It looks for the log file, processes it, then deletes it (so the next sftp upload can overwrite).

NOTE: processPDULogs must have read/write access to $logdir and, obviously, so must the sftp server.

The second script, getPDU, is used to read the file. When called with the name of the PDU and the key to be read, returns the value (useful for Zabbix monitoring, http://zabbix.com)

processPDULogs

#! /usr/bin/perl
 
# Script reads data log produced by APC AP7940 which if ftp'd to $logDir
# it finds the last entry read (from status file) and scrolls down through
# log file until it finds the next entry.
# then summarizes the entries (only happens once an hour) and stores the value
# in the out file.
 
# Copyright 2015, Rod, Daily Data, Inc.
# Free to use, modify, change, anything you want
# You do NOT have to give attribution, but it would be 
# appreciated.
# Also, if you make changes and want to give them back, just send them to 
# us. Visit the http://www.dailydata.net and select Contact Us
 
my $logDir = '/home/apcpdu'; # location where log is ftp'd to by AP7940
my @PDUNames = ('pdu1','pdu2'); # names of pdu's to look for
my $logFileExtension = 'log'; # extension expected for log file name
my $statusExtension = 'status'; # extension used for recording last record processed
my $outputFileExtension = 'out'; # extension used for most recent summary
my $voltage = 208; # could not figure out how to get voltage from pdu, so hard coded
my $pf = 1; # ditto power factor
 
 
foreach my $thisLog ( @PDUNames ) {
   my $statusFile = $logDir . '/' . $thisLog . '.' . $statusExtension;
   my $logFile = $logDir . '/' . $thisLog . '.' . $logFileExtension;
   my $outFile = $logDir . '/' . $thisLog . '.' . $outputFileExtension;
   my @log;
   my $status = 0;
#   print "Processing log from $thisLog\n";
   if ( -f $statusFile ) {
#      print "\tReading $statusFile\n";
      open STATUS, "<$statusFile";
      $status = <STATUS>;
      close STATUS;
   } 
   if ( -f $logFile ) {
#      print "\tReading  $logFile\n";
      open LOG,"<$logFile" or die "Could not read $logFile: $!\n";
      my $log = join( '', <LOG> );
      @log = split( "\n", $log );
      close LOG;
   } else {
      next;
   }
   chomp @log;
#   print "\tTrying to find header\n";
   my $line = 0;
   while ( $line < @log ) {
      last if $log[$line] =~ m/Date\s+Time\s+I\s+IMax\s+IMin/;
      $line++;
   };
#   print "\tFinding first line to process\n";
   if ( $status ) {
      while ( $line < @log && $log[$line] ne $status ) {
         $line++;
      }
   }
   $line++;
   # we should now be at the first entry AFTER the last one read
#   print "First line to process would be line $line\n$log[$line]\n";
   my $max = 0;
   my $min = 1000;
   my $sum = 0;
   my $count = 0;
   my $datetime; # last date and time read
   while ( $line < @log ) {
      my ($date,$time,$current,$currentMax,$currentMin) = split( /\s+/, $log[$line]);
      $max = $currentMax if $currentMax > $max;
      $min = $currentMin if $currentMin < $min;
      $count++;
      $sum += $current;
      $datetime = "$date $time";
      $line++;
   }
   next unless $count;
   open LOG,">$outFile" or die "Could not write to $outFile: $!\n";
   print LOG "timestamp\t$datetime\n";
   print LOG "average\t" . $sum/$count . "\n";
   print LOG "max\t$max\n";
   print LOG "min\t$min\n";
   print LOG "count\t$count\n";
   print LOG "voltage\t$voltage\n";
   print LOG "pf\t$pf\n";
   close LOG;
   `chmod 666 $outFile`;
   open STATUS,">$statusFile" or die "Could not write to $statusFile: $!\n";
   print STATUS $log[scalar(@log)-1];
   close STATUS;
   `mv $logFile $logFile.old`;
}
 
1;

getPDU

#! /usr/bin/perl -w
 
# script to get pdu data from summary file created by
# processPDULogs. Simply reads file pduname.out in $outputDir
# with pduname being the value of the first parameter
# returns the entry from the tab delimited file in the form
# key value
# where key is passed in as the second value
 
# Copyright 2015, Rod, Daily Data, Inc.
# Free to use, modify, change, anything you want
# You do NOT have to give attribution, but it would be 
# appreciated.
# Also, if you make changes and want to give them back, just send them to 
# us. Visit the http://www.dailydata.net and fill out the contact form
 
my $pduName = shift;
my $key = shift;
 
my $outputExtension = 'out';
my $outputDir = '/home/apcpdu';
 
# retrieve one value (based on $key) from $datafile
sub getValue {
   my $datafile = shift;
   my $key = shift;
   return -1 unless $key;
   # open data file and get line with key in it
   # maybe faster using grep???
   open DATA, "<$datafile" or die "No data to read: $!\n";
   my @lines = grep { /^$key\t/ } <DATA>;
   close DATA;
   # clean up line and return the value (second field of tab delim line)
   chomp( $lines[0] );
   ($key,$value) = split ("\t", $lines[0] );
   return $value;
}
 
die "Invalid PDU name" unless $pduName;
my $filename = "$outputDir/$pduName.$outputExtension";
die "No Datafile" unless -e $filename;
 
die "No key given" unless $key;
 
print getValue( $filename, $key );
 
1;