Search results
Sign-up and receive our weekly updates including the latest news and technical articles. Premier publication and forum for control and automation engineers providing educational material, tools, industry insight, videos and conferences.
Programmable Logic Controller - PLC. A forum for industrial controllers that can automate a specific process, machine function, or even an entire production line. Issues running a program on the Arduino Opta. Program uploads just fine but won't execute.
Relays are magnetic electromechanical devices with two primary purposes: to isolate different circuit voltages, and to form larger complex networks of logic to run machines without digital controllers. An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices, they exhibit simple “on” and ...
Cascade Control - Nested Feedback Loops. To cascade controllers means to connect the output signal of one controller to the setpoint of another controller, with each controller sensing a different aspect of the same process. The first controller (called the primary, or archaically, master) essentially “gives orders” to the second controller ...
Importance of proper valve sizing. The flow coefficient of a control valve (C v) is a numerical value expressing the number of gallons per minute flow of water the valve will pass with a constant pressure drop of 1 PSI from inlet to outlet. This rating is usually given for the valve in its wide-open state.
Now, control system response will be consistent at all points within the controlled flow range, which is a significant improvement over the original state of affairs. Control valve trim is manufactured in a variety of different “characteristics” to provide the desired installed behavior.
Feedforward Control. “Feedforward” is a rather under-used control strategy capable of managing a great many types of process problems. It is based on the principle of preemptive load counter-action: that if all significant loads on a process variable are monitored, and their effects on that process variable are well-understood, a control ...
Control valves are comprised of two major parts: the valve body, containing all the mechanical components necessary to influence fluid flow; and the valve actuator, providing the mechanical power necessary to move the valve body components. Often times, the major difference between an on/off control valve and a throttling control valve is the ...
In control systems where valves are split-ranged in either complementary or exclusive fashion, one control valve will be fully closed and the other will be fully open at each extreme end of the signal range (e.g. at 4 mA and at 20 mA). If the sequencing for a set of complementary or exclusive split-ranged control valves happens after the controller (e.g. different actuator actions) the valves ...
Apr 12, 2023 · 2-Wire Control Examples. As an example of this control, let us examine the Commander S100 drive by Control Techniques. This drive has 5x digital inputs, each with a factor-specific default function. Figure 2 below shows the default configuration. A digital device connected to Dig Ins 2 and 3 will allow 2-wire bi-directional control. Figure 2.
