A baler (10) is disclosed. The baler (10) comprising: a baling chamber (82), a plunger (26) movable with respect to the baling chamber (82)； a bale case (86)； a first sensor (126) operable to measure the force applied to the plunger (26)； a second sensor (134) operable to measure movement of a formable bale (32) with respect to the bale case； and a controller (14) in operable communication with the first sensor (126), the second sensor (134), and the plunger (26), the controller (14) configured to: calculate the force applied to the plunger (26) over a predetermined period of time based at least in part on readings from the first sensor (126), calculate the distance a formable bale (32) has moved with respect to the bale case (86) over the same predetermined period of time based at least in part on readings from the second sensor (134), calculate the work exerted by the plunger (26) at least partially based on the force applied to the plunger (26) and the distance a formable bale (32) has moved with respect to the bale case (86)； and compare the work calculation with one or more pre-calculated parameters.
