Powerful Programming Instruction Simplifies AC Power Monitoring

The addition of a new instruction into the CRBasic programming language means that Campbell Scientific (UK) dataloggers, in a single line of code, can provide a great deal of detail about a single or three phase AC power system. The simple but powerful ACPower instruction in CRBasic allows CS loggers to measure power, voltage and current for each phase, plus total power, voltage frequency, voltage phase in radians and the voltage harmonics ratio.

A system recently installed at Campbell Scientific's European HQ, uses this instruction to monitor the company's power consumption on its three phase supply in preparation for a major solar power installation. The system is relatively simple consisting of a CR1000 datalogger which measure three voltage transformers and three current transformers – one for each phase. An NL200 connects the datalogger to the company’s network and data is viewed in real time on a customised RTMCPro screen.

The system is monitoring the company's electrical power demand as its new 50 kW, 200 panel photovoltaic (PV) installation is commissioned. The installation, across 5 roof areas should, on a sunny day, see the company become self-sufficient for electricity and at weekends and holidays the company will generate and feed-in significant power back into the grid.