Apparatus and method for controlling reciprocating pump

A controlling method for a preparative separation-purification system, comprising:

• providing a solution container;
• at least one trap column;
• a pump housing;
• a moving component for reciprocating in the pump housing so as to draw a liquid into the pump housing and discharge the liquid from the pump housing, wherein the moving component starts moving from any position which varies within its range of motion;
• a driving source for reciprocating the moving component;
• and a controlling apparatus;
• setting a target liquid supply amount;
• computing, based on a discharge amount of the pump housing per a reciprocal movement of the moving component, a smallest multiple number of the discharge amount per the reciprocal movement of the moving component where the smallest multiple number of the discharge amount is obtained by rounding up figures after a decimal point of a ratio of the target liquid supply amount over the discharge amount;
• and
• controlling the driving source so that the moving component stops at a same position at which the moving component starts moving by making the moving component reciprocate a same number of times as the smallest multiple number of the discharge amount, wherein said same position is any position which varies within the moving component's range of motion.

A preparative separation-purification system comprising:

• a solution container;
• at least one trap column;
• a reciprocating pump having a pump housing;
• a moving component for reciprocating in the pump housing so as to draw a liquid into the pump housing and discharge the liquid from the pump housing, wherein the moving component starts moving from any position which varies within its range of motion;
• a driving source for reciprocating the moving component;
• and
• a controlling apparatus including:
• a setting section configured to set a target liquid supply amount or a target liquid supply time which corresponds thereto;
• a unit amount memory section configured to store (i) a unit discharge amount of the reciprocating pump per a reciprocal movement of the moving component and/or (ii) a unit driving time which corresponds to the unit discharge amount;
• a computation section configured to compute a smallest multiple number (i) where the smallest multiple number is obtained by rounding up figures after a decimal point of a ratio of the target liquid supply amount over the unit discharge amount or (ii) where the smallest multiple number is obtained by rounding up figures after a decimal point of a ratio of the target liquid supply time over the unit driving time;
• and
• a motor controller configured to control the driving source so that the moving component stops at a same position at which the moving component starts moving by making the moving component reciprocate a same number of times as the smallest multiple number, wherein said same position is any position which varies within the moving component's range of motion.