Continous CP Potentials
The Polatrak® ROV II probe has dual Ag/AgCl half cells, allowing both contact and continuous potential measurements to be taken. The analog potential measurements are converted to a digital output subsea by the Deep C Meter, which is rated to 3000 m. Data can be transmitted using either RS485 or RS232 protocols through the ROV multiplexor to the surface computer.
Field Gradient Measurements
The Polatrak® EFG probe also has dual Ag/AgCl half cells, to record close filed gradient measurements. In addition, a remote electrode deployed from the vessel allows for a larger field gradient reading.These measurements are also digitized and imported into the logging software.
The Polatrak® ROV II contact readings are essential to calibrate the survey from time to time, in order to tie remote potential back to the actual potential of the steel pipeline. Ensuring good calibration stabs will produce a more accurate pipeline profile.