The frequency changer uses water chestnut branch LK600 is high performance air blower water pump special-purpose frequency changer 18, male rate from 7.5-160KW. This frequency changer has: 485 correspondences connections, in set from the study type PID closed-loop control, the 4-20MA standard signal input, the 4-20MA feedback signal output, function and so on frequency conversion breakdown output electronic contact connection, the product design achieved with the DCS comprehensive communication, the movement is accurate meets the design side requirements not by mistake.