Surgical instrument system configured to evaluate the load applied to a firing member at the initiation of a firing stroke

A surgical instrument assembly, comprising:

• an end effector configured to capture tissue;
• an electric motor, wherein said electric motor is couplable with a power supply;
• a rotatable drive shaft operably coupled with said electric motor, wherein said rotatable drive shaft is configured to drive a firing drive during a firing stroke;
• and
• a sensing system configured to detect a load applied to said firing drive at an initiation position of said firing stroke, wherein when the load exceeds a threshold value before, but not after, said firing drive surpasses a predetermined distance from said initiation position, said firing drive is prevented from continuing said firing stroke.

A surgical instrument assembly, comprising:

• an end effector configured to capture tissue;
• an electric motor, wherein said electric motor is couplable with a current supply;
• a rotatable drive shaft operably coupled with said electric motor, wherein said rotatable drive shaft is configured to drive a firing drive during a firing stroke;
• and
• a lockout circuit configured to sense current through said electric motor, wherein said lockout circuit is further configured to interrupt the current through said electric motor and prevent said firing drive from completing said firing stroke when the sensed current exceeds a threshold value and said firing drive is within a predetermined distance from an initiation position.

A surgical instrument, comprising:

• an end effector configured to capture tissue;
• an electric motor comprising a rotatable output;
• a power supply couplable with said electric motor to supply power to said electric motor;
• a firing member operably coupled with said rotatable output, wherein said firing member is movable from an unfired position to a fired position to transect the tissue captured by said end effector;
• and
• a sensor configured to produce a signal corresponding to a load applied to said firing member, wherein when the load exceeds a threshold value and said firing member is within a predetermined distance from said unfired position, said firing member is prevented from moving toward said fired position.