Glossary

An electromagnetic feedback transducer providing an analog voltage signal proportional to rotational speed.

A software system control that determines the execution rates and priority levels for software modules running in a motion control or PLC.

Transmission Control Protocol/Internet Protocol. A method of encoding data into a series of "packets" for transmission over a network. Designed initially for use on the Internet, TCP/IP is rapidly penetrating non-Internet uses, including the factory floor.

The position of an axis that is “taught” into the motion control program. The axis is moved, typically by jogging, to the desired position. This “ teach position” is then entered into the motion program automatically by the control (using whatever steps are required by the motion control manufacturer) and becomes the new Programmed position. The motion control used must have the ability to do this type of program manipulation.

Communication data packet between controller and device.

Velocity Loop Integral Action Time. Associated with KP. When velocity error occurs outside of the tolerance value set in KP, TN determines how quickly the servo drive will bring the velocity back within the specified tolerance. See also: Tuning

A measure of angular force which produces rotational motion. This force is defned by a linear force multiplied by a radius; e.g. lb-in.  Formula: Torque (lb-ft.) = 5,250 x HP/RPM

An expression of the relationship between input current and output torque. For each ampere of current, a fixed amount of torque is produced. NOTE: Torque constants ARE NOT linear over the operating range of a motor. They apply best at -75o of no load maximum speed or where the peak and continuous torque curves meet.

A servo function that allows the monitoring and limiting of the current supplied to a servo motor.

Defined as the motor's holding torque divided by the inertia of its rotor. The higher the ratio, the higher a motor's maximum acceleration capability will be.

Adjusting the servo drive’s internal characteristics to give it the ability to control the reflected inertia and gives the axis a smooth position/velocity profile. The process of Tuning involves setting the Velocity Loop Proportional Gain (KP), Position Loop Gain (KV), and the Velocity Loop Integral Action Time (TN) values so that the axis has a position/velocity profile allowing only as much position/ velocity error as the process will permit.

Twisted pair