UPS Power Monitoring from CAS DataLoggers Solves Voltage Problems

Single Phase 300Vac Data Logger Kit Pinpoints Power Dropouts

Recently CAS DataLoggers Applications Specialist Pat Picciano recommended the EC-1V Single Phase Voltage Logger Kit to solve a customer’s UPS (Uninterruptible Power Source) power drops, revealed when the owner returned to work in the mornings and saw repeated indications of voltage problems. The UPS powered the company’s backup server, phone system, voicemail server, and more, so the owner needed a monitoring solution that fit into a modest budget.

Users just plugged the data logger into the wall and set the single phase logger to stop recording when the memory was full. Recording was shown by a green light and completion by a red light. The kit included the data logger, carrying case, free Windows software, and an RS- 232 serial lead.

Commonly used for pre- and post-installation analysis, the Single Phase 300Vac data logger recorded voltage and saved 3 quantities for each channel at the end of each averaging period: the True RMS average, the Max, and the Min. This meant that it recorded all the highs and lows which were one cycle or longer, storing all this information in non-volatile memory.

The datalogger used a constant sampling technique to sample every channel 16 times per cycle (16ms at 60Hz and 20ms at 50Hz), and users could choose the duration recorded from 1x a second to 1x an hour. The single-phase recorder was then left for 20 days to highlight the voltage problem. Low readings for the UPS would be about 85V, and normal readings would average around 120V, with problem readings beginning around 100-85V.

Voltage Drops GraphNormal and reliable operation would be represented by a flat line graph, but that’s not what the customer saw after analyzing it using the included software. The stored data was uploaded to a PC via the supplied RS-232 cable, and then the recorded voltage levels, dates & times were viewed in both tabular and graphical form, exported to a spreadsheet and saved to file. Users quickly saw that the power experienced major dropouts at midnight for 7 days out of the 20 logged, showing the customer had a real problem. These graphs were then printed out to clearly show all the recorded voltage output.

The voltage logger kit worked well for the customer as a low-cost solution—it was small, safe and easy to use. In fact, several employees would check the readings since it didn’t need special training to set it up or use it. The data from the graphs let the customer know that their UPS was probably the culprit, which they quickly replaced, fixing the problem and keeping everything online 24/7. The data logger effectively allowed the customer to cost-effectively monitor their voltage supply and highlight subsequent voltage problems quickly for further investigation.