Mitsubishi Electric PLC Control Units, Counter, High Speed, MELSEC-F Series, Type: Counter, Channel number(ch): 4, Count Input Format: Differential line receiver, Maximum Response Frequency (1 Phase, 1 Input): 200 kHz or less (according to the sequence program), Maximum Response Frequency (1 Phase, 2 Input): 200 kHz or less (according to the sequence program), Maximum Response Frequency (2 Phase Input): 100 kHz or less (according to sequence program)