Instrument for the controlling of high pressure inside punches, during the pressing cycle. It uses a proximity switch, a pressure transducer, an MPC control and an acoustic plus visual alarm. At the start of the cycle, which usually coincides with the carriage start, the MPC receives an impulse from the sensor placed near the carriage and a timer starts counting for 30 seconds. If within this time the pressure transducer does not detect a pressure equal to the one set on the display (usually 40 BAR under the specific compressing pressure), an acoustic plus visual alarm will be set off.