Hardware scalers for all four channels and the trigger working up to 200 MHz. With the trigger scaler one can measure for example coincidence rates between two channels.
Does it give the ability to measure triggering rate? I'm talking again about possibility of use DRS4 as pulse counter for PMT's. If yes, do I need new v5 board or it is possible to use v4 board?
Yes it is possible to measure the raw trigger rate, with a resolution of 10 Hz. You need a new V5 board for that.