Method of and system for electrically processing vacuum pressure information suitable for use in vacuum unit

A method of electrically processing vacuum pressure information, which is suitable for use in a vacuum unit in which a workpiece is attracted or released under suction, said method being executed by a vacuum control apparatus and comprising the steps of:

• providing a plurality of pressure sensors disposed at different positions in the vacuum unit;
• detecting pressure values at said different positions in the vacuum unit upon attraction and release of the workpiece;
• displaying a desired pressure value on a displaying means in digital form, said desired pressure value being lower than a highest vacuum pressure value of a plurality of sequential pressure values detected by at least one of said pressure sensors;
• storing said desired pressure value in a storing means;
• converting each of said sequential pressure values into digital signals, said sequential pressure values being detected by a pressure detecting element held in front of a passage which communicates with a vacuum port, and thereafter digitally displaying the converted digital signals on said displaying means;
• comparing said desired pressure value stored in said storing means with each of said sequential pressure values;
• determining improper operation of said vacuum unit based on a result of the comparison of said desired pressure value stored in said storing means with each of said sequential pressure values;
• and
• after the improper operation of said vacuum unit has been determined at said determining improper operation step, said method comprises the step of:
• determining a failure point in said vacuum unit which includes the steps of:
• (a) detecting a further pressure value at a position upstream from a component in said vacuum unit through one of said plurality of pressure sensors located at said position upstream from said component in the vacuum unit;
• (b) detecting a further pressure value at a position downstream from said component through a further one of said plurality of pressure sensors located at said position downstream from said component;
• (c) determining a differential pressure between the detected further pressure values upstream and downstream from said component;
• and
• (d) comparing said differential pressure with a predetermined threshold value;
• and
• displaying information about said failure point on said displaying means based on a result of said comparison of said differential pressure with said predetermined threshold value.