... frequency(AC 0-- 600V),range:0.01Hz--100KHz(max 100KHz),accuracy:0.01Hz,Applicable to equipment for control of frequency,tacho,line-speed,level ... automatically;Opical isolation for input and output,high anti-interference.4, Output:up to 3 alarm output with various output modes ... selectable:high value,low value ,intervals,etc;analogue output 4-20mA or 0-10mA with range settable.5, RS232 or RS485 Modbus ...