My UPS under Debian with NUT

I purchased a Powercom UPS from Elect Power Technologies in Perth, Western Australia in September 2001. This was badged as a PowerTech on the front of the UPS, but the model is identified (by the RS232 interface) as a "Powercom ULT-1000" (see

I was attempting to get UPS-Monitoring software under Debian/GNU Linux. I settled on NUT, and after some help from Dan at Fenton, and Russell from the NUT project, I found that this UPS is speaking the Megatec protocol, as documented on the NUT site.

At the time, the driver for this protocol was the fentonups driver, but it had no support for this model. I determined the required lines in fentonups.h that match this model's characteristics, and submitted them to Russell.

I also wrote a small Perl script to open the serial port and get some stat back. You can grab that script if you like, but you should use NUT for production systems. I wrote this just for testing.

If you have a UPS that you suspect is talking this protocol, play with the Perl script, and figure out the values you need to add to fentonups.h.

The following excerpts are taken from the manual that came with the UPS.


Uninterruptible Power System
Unterbrechungsfreie Stromversorgung

ON LINE Network Protection
ON LINE Pure Sine Wave Output UPS
700VA/ 1000VA/ 1500VA/ 2KVA/ 3KVA

Revision 1.0. Revised September 15, 2000.

Computer Interface
Pin # Function I/O
2 Power Fail - normally status, will become closed during active OUTPUT
4 Reference GND for pin 2,5 OUTPUT
5 Battery Low - normall open status, will become closed during active OUTPUT
6 Remote shutdown UPS - keep this pin at high voltage (+5V ~ +12V) 500 ms to shut down UPS. Activates battery mode INPUT
7 Reference GND for pin 6 INPUT
Tower model 700VA 1000VA 1500VA 2000VA 3000VA
19" rack mount model 700VA RM 1000VA RM 1500VA RM 2000VA RM 3000VA RM
Power Rating P.F.=0.7 700VA/490W 1KVA/700W 1.5KVA/1050W 2KVA/1400W 3KVA/2100W
AC Input Voltage
  • 100V: 76V - 130V
  • 110V: 80V - 138V
  • 115V: 83.5V - 140V
  • 120V: 87V - 140V
  • 208V: 152V - 260V
  • 220V: 160V - 276V
  • 230V: 167V - 280V
  • 240V:174V-280V
Frequency 50 Hz ir 60Hz +/- 3Hz
Phase Single phase
Power Factor 0.98
Battery DC Voltage 24V 36V 48V 72V 96V
Back-up Time Full Load 5 min 7 min 5 min 9 min 7 min
Half load 12 min 20 min 17 min 20 min 15 min
Type Seal lead acid battery, free maintenence (sic)
Protection Cut off without draining any current when battery low
Recharge time About 8 hours to 90% after fully dischaged
AC output Frequency 50Hz/60Hz (Auto detection)
Voltage 100/110/115/120V or 208/220/230/240 V
Voltage Regulation +/- 2% (except 3000 VA/110V +/- 3%, 3000 VA RM/110V +/- 3%)
Frequency Stability +/- 0.5%
Power Factor 0.7 (lagging)
Harmonic distortion < 3% of T.H.D. at linear load
Overload detection 105% for 10 seconds and 130% +/- 10% for 300 ms
Effeciency AC to AC >85%
Transfer Power failure or recovery 0ms
Overload disappear Auto transfer to UPS
Noice Level 1m. distance < 45 dBA <52 dBA
LED Indicators Status line input (green), inverter output (green), bypass (yellow), fault (red)
Battery capacity 4 green, 1 red LED and red bar LEDs indicated low capacity
Load level 4 green, 1 red LED and red bar LEDs indicated overload capacity
Alarm Battery discharge The first warning will beep every 4 seconds to indicate battery in use. The second warning will beep every 1 second to signal battery low condition.
UPS Fault Continuous beeping sound
Environmental Temperature 0 * C - 40 * C
Humidity 0% - 95% (Non condensing)
Interface Support both RS232 & dry contact signal Provide power managment and diagnostic functions including power status, battery low, shecule UPS ON/OFF, battery load level display and more compatible with Windows 95/98/NT, Novel, Unix, and other popular systems.
Physical Size (WxDxH (mm) Tower model 145 x 400 x 220 192 x 460 x 385
19" rack-mount 483 x 400 x 130 483 x 470 x 130
Net weight (Kg) Tower model 8.9 11.3 13.9 28.1 33.3
19" rack-mount 21.1 23.5 26.1 27 31

2000.09.05 Version 1.0 Powercom Co., Ltd. All Rights Reserved. All trademarks are propery of their respective owners. Specifications subject to change without notice.