What is PV Tracking ?
Setpoint Tracking (also called PV tracking): PV Tracking is An option on many controllers. When a control loop is in MANUAL, with PV Tracking turned on, the controller setpoint (SP)…
Cat and Mouse type Level Indicator
Cat and Mouse type is particularly suited to indicating contained liquid levels when viewed from long distances, e.g. provides indication at 1:1 ratio on a large vertical scale board fixed to…
P&ID Guidelines for Control Valves
A piping and instrumentation diagram/drawing (P&ID) is a diagram in the process industry which shows the piping of the process flow together with the installed equipment and instrumentation. P&ID Guidelines…
What is a Thermopile ?
A thermopile is an electronic device that converts thermal energy into electrical energy. It is composed of several thermocouples connected usually in series or, less commonly, in parallel. Thermocouples operate…
What to Choose RTD or Thermocouple ?
Thermocouples (TCs) and resistance temperature detectors (RTDs) are the most widely used temperature sensors in automation and process control. They are found embedded in motors, valves, turbines, bearings, and a…
How a 4 Wire RTD Works ?
4 Wire RTD Principle The most accurate lead wire configuration is the “true” 4-wire configuration. In a true 4- wire configuration, the resistance of the lead wires does not contribute…
What is PID Controller Bumpless Transfer ?
Bumpless Transfer Bumpless transfer is either a manual or automatic transfer procedure used when switching a PID controller from auto to manual or vice versa. Its aim is to keep…
Feedforward Vs Feedback Control
Feedback control Feedback control is an important technique that is widely used in the process industries. Its main advantages are as follows. Corrective action occurs as soon as the controlled…
PID Controllers with Output High Select Logic
The below figure 1 shows a typical control scheme with two controllers driving the same control valve via high select logic. The controller PIC-1 is the main pressure controller and…
