Process variable

About: Process variable is a research topic. Over the lifetime, 3983 publications have been published within this topic receiving 43130 citations. The topic is also known as: process parameter.

Method and arrangement for process control in spot welding

Abstract: A method and an arrangement for process control in spot welding are described in which the mechanical and/or electrical process variables predetermined for the welding process are monitored during the welding and each change in the process variable within the welding operation can be readjusted via several manipulated variables. The welding process is subdivided into several areas for the control, an evaluation scheme being allocated to each of these areas. The curve behaviour for various materials and dimensions is determined on actual components and stored. Calibration of the welding machine is dispensed with.

Model predictive control using wireless process signals

Abstract: A multiple-input/multiple-output control routine in the form of a model predictive control (MPC) routine operates with wireless or other sensors that provide non-periodic, intermittent or otherwise delayed process variable measurement signals at an effective rate that is slower than the MPC controller scan or execution rate. The wireless MPC routine operates normally even when the measurement scan period for the controlled process variables is significantly larger than the operational scan period of the MPC controller routine, while providing control signals that enable control of the process in a robust and acceptable manner. During operation, the MPC routine uses an internal process model to simulate one or more measured process parameter values without performing model bias correction during the scan periods at which no new process parameter measurements are transmitted to the controller. When a new measurement for a particular process variable is available at the controller, the model prediction and simulated parameter values are updated with model bias correction based on the new measurement value, according to traditional MPC techniques.

Process monitoring technique and related actions

Abstract: The invention provides a novel method of monitoring a process. The method also has the ability to take predetermined actions based on the monitored data. These actions avoid or mitigate process abnormalities or upsets that might impact product quality, production, and/or process efficiencies. The method includes the steps of: obtaining at least one input process variable; determining a comparative process value based on the at least one input process variable using a first method having a first time-based weighting function; determining an expected process value based on the at least one input process variable using a second method having a second time-based weighting function; determining a first deviation value based on the at least one input process variable or historical data; calculating a limit range having a maximum limit and a minimum limit using the expected process value and the first deviation value; and comparing the comparative process value to the limit range.

Process control loop signal converter

Abstract: A device for use in a process control system includes a first pair of electrical connections configured to couple to a two-wire process control loop. The loop includes a two-wire process variable transmitter. A second pair of electrical connections is configured to couple to an input channel of a process device having multiple input channels. An electrical component is connected in series in the loop for use in digital communication with the two-wire process variable transmitter.