Patent US 4,175,283

A Batch Option Module is provided for a process control instrument. Whenever the process control instrument reaches the limits of its control range, the Batch Option Module is activated to limit the output of the instrument as a function of the process variable, the setpoint, and an adjustable bias. When the output of the instrument due to normal control action no longer trys to exceed the Batch Option Module limit, the Batch Option Module is deactivated.