Linux Power Line Monitor

Overview

This document describes how to set up a Linux computer with apcupsd connected to an APC uninterruptible power supply to monitor the state of the AC powerline. The voltage is plotted on a web page and email or telephone alarms can be sent to anyone concerned about power fluctuations.

Hardware connections

The APC UPS uses a nonstandard cable (940-0024C) that resembles a serial cable. However, if you attach a standard serial cable to the APC, the UPS will shut off as soon as the cable is attached to a computer. It is possible that some newer UPS models no longer have this feature.

APC 940-0024C UPS Cable

Installation of apcupsd

This information is taken from the 195-page apcupsd manual written by Kern Sibbald and applies to apcupsd version 3.10.17. The manual should be consulted for authoritative or complete information.

It is recommended to plug your computer into the wall instead of the UPS when testing, because APC UPSs will shut down if the wrong cable is attached, if you make a configuration mistake, or if you send certain characters out the serial port during testing.

  1. Build apcupsd 
    ./configure --prefix=/usr --sbindir=/sbin --enable-usb \
--enable-cgi --with-cgi-bin=/usr/local/httpd/cgi-bin \
--enable-pthreads
    (omit enable-usb if your UPS uses a pseudo-serial or serial cable) 
    make
su
/etc/rc.d/apcupsd stop  (to stop any running instance of apcupsd)
  2. Uninstall any old apcupsd-related files
    • locate apcupsd or whereis apcupsd followed by rm
    • remove old apctest
    • remove old apcupsd
    • remove old /etc/apcups.d
    • remove old acpaccess
    • remove old apcnisd
  3. Install apcupsd 
    cp /etc/rc.d/halt /etc/rc.d/halt.bak
  (or /etc/rc.d/init.d/halt in Red Hat)
make install
  4. Edit /etc/apcupsd/apcupsd.conf
    • UPSTYPE - set to dumb, apcsmart, smartups usb, net, snmp, or ether
    • UPSCABLE - set to the cable type = smart
    • DEVICE /dev/ttyS0
    • if you have a USB UPS, comment out DEVICE
    • UPSMODE disable
    • NETSERVER on
    • NISIP 63.127.146.192
    • NISPORT 3551
    • EVENTSFILE /var/log/apcupsd.events
    • STATTIME 60
    • STATFILE /var/log/apcupsd.status
    • MONITOR endive "The Server"
  5. Check /etc/rc.d/halt script to make sure it was properly updated.
  6. Start apcupsd with /etc/rc.d/apcupsd start (etc/rc.d/init.d/apcupsd start in Red Hat)

Communicating with the UPS

The file /var/log/apcupsd.status is updated once per minute. Different UPSs provide different amounts of information. The Smart-UPS 1000 gives the following: 
APC      : 001,052,1230
DATE     : Fri Aug 19 17:30:57 EDT 2005
HOSTNAME : endive
RELEASE  : 3.10.18
VERSION  : 3.10.18 (21 July 2005) suse
UPSNAME  : UPS_IDEN
CABLE    : APC Cable 940-0024C
MODEL    : SMART-UPS 1000
UPSMODE  : Stand Alone
STARTTIME: Fri Aug 19 17:21:22 EDT 2005
STATUS   : ONLINE 
LINEV    : 117.6 Volts
LOADPCT  :  76.4 Percent Load Capacity
BCHARGE  : 100.0 Percent
TIMELEFT :  17.0 Minutes
MBATTCHG : 5 Percent
MINTIMEL : 3 Minutes
MAXTIME  : 0 Seconds
MAXLINEV : 118.9 Volts
MINLINEV : 117.0 Volts
OUTPUTV  : 117.6 Volts
SENSE    : High
DWAKE    : 000 Seconds
DSHUTD   : 020 Seconds
DLOWBATT : 02 Minutes
LOTRANS  : 103.0 Volts
HITRANS  : 132.0 Volts
RETPCT   : 000.0 Percent
ITEMP    : 35.1 C Internal
ALARMDEL : 5 seconds
BATTV    : 27.7 Volts
LINEFREQ : 60.0 Hz
LASTXFER : Automatic or explicit self test
NUMXFERS : 0
TONBATT  : 0 seconds
CUMONBATT: 0 seconds
XOFFBATT : N/A
SELFTEST : NO
STESTI   : 336
STATFLAG : 0x02000008 Status Flag
DIPSW    : 0x00 Dip Switch
REG1     : 0x00 Register 1
REG2     : 0x00 Register 2
REG3     : 0x00 Register 3
MANDATE  : 05/24/00
SERIALNO : QS0022213176
BATTDATE : 05/24/00
NOMOUTV  : 115
NOMBATTV :  24.0
EXTBATTS : 0
FIRMWARE : 60.11.D
APCMODEL : IWD
END APC  : Fri Aug 19 17:30:59 EDT 2005
Typing "apcaccess status" gives the same information"; for example; 
apcacces status sendive:3551
Make sure NISIP is to an appropriate subnet mask, or people on the Internet may start trying to hack into your UPS. The utility "apctest" enters interactive mode, allowing you to perform various tests, including battery runtime calibration.

Make sure cgi is enabled in your web server.

Edit /etc/apcupsd/hosts.conf and add a line for each computer running upsd. This is used by multimon to monitor multiple UPSs and by upsstats to provide information.

Back