V0N_hydro
Member
I want to measure the period of a 60Hz signal with .001 Hz accuracy resolution. The Schneider M430 high speed counter BMX EHC 0200 has a resolution of 1 us (so 1MHZ counter clock), which yields a resolution of 0.0036 Hz. This signal always varies by +- 0.0036 Hz. Using a filter with time constant of 33ms (two periods) averages out this noise and provides a decent signal, but doesn't achieve .001 Hz and I would prefer to add as little delay as possible.
I know there is an allen bradley high speed counter with resolution of 0.25 us so 4 MHz counter clock, and this would provide frequency measuring resolution of 0.0009 Hz, so I can expect the the measured frequency to constantly vary by +- 0.9 milliHz, so I still have 1 milliHz noise.
What PLC has the fastest counter for measuring the period of a square wave? Do I have to move away from PLC type devices for counters approaching 10MHz?
I know there is an allen bradley high speed counter with resolution of 0.25 us so 4 MHz counter clock, and this would provide frequency measuring resolution of 0.0009 Hz, so I can expect the the measured frequency to constantly vary by +- 0.9 milliHz, so I still have 1 milliHz noise.
What PLC has the fastest counter for measuring the period of a square wave? Do I have to move away from PLC type devices for counters approaching 10MHz?