Relay coil instructions can be used to control either external PLC outputs or internal relay coils (bits) in the PLC. You can see an example of the use of relay instructions in Rung 1 of Fig. 1.

A relay coil, whether it's a discrete device or a “virtual” device mimicked by PLC software, controls one or more sets of contacts. When a relay coil is energized or “picked up,” its type-A contacts ...

The control pin is pulled to ground to keep the relay off. A diode is placed across the relay coil to manage the power flow when it discharges. An indicator LED is included to show when the relay ...

This Design Idea shows how to use a 63¢ (Q=1) microprocessor reset voltage detector IC in a relay coil drive circuit to greatly reduce the coil’s hold-in current. When asked to estimate the coil ...

Instead, his coil uses a relay in place of a spark gap. [Teodor] built his coil using leftover components from his old school, making good use of some parts that might have otherwise been thrown away.

Designed to interface PC or PLC logic to machines, the Releco Interfacer universal relays pack both ac and dc circuits in the same unit and include a built-in surge supressor. Dedicated ac or dc ...

Not so long ago the engineer would construct a device employing dozens of relays ... In some PLC architectures, the programmer is allowed to freely use an object, or in programming terms, to ...

Latching relays change their states when you apply a short voltage pulse to their coils. Because these relays require no continuous coil currents to keep their states, you can save considerable power ...

Schweitzer Engineering Laboratories, Inc. has released the SEL-2652 Trip Coil Monitor to provide critical information to engineers and operators. Today’s power system depends on reliable circuit ...