SZD-S-2, SZD-S-4, SZD-2, SZD-3 type single-impulse liquid level controller, and SZD-S, SZD-S-3 type double-impulse liquid level controller, are re-developed and improved on the basis of original various instruments according to user requirements, so that the above various instruments are unified, standardized and standardized for easy selection and use by users or design departments. The instrument can select the liquid level input signal (liquid level inductance input or 0~10mA, 4~20mA standard signal input) by switching jumpers, and can adjust the valve position feedback signal (0~10mA, 4~20mA or resistance signal) by themselves to make the application range wider.