Why relays are used with PLC?
Relays are used to isolate one voltage level from another. A PLC may be used to control the operation of a medium-voltage motor, perhaps 2,300V or 4,160V. A relay is used to energize the starter, which, in turn, switches the motor voltage while the PLC controls the relay.
What are the different types of relays and what do they do?
Relays are either electromechanical relays or solid-state relays. In electromechanical relays (EMR), contacts are opened or closed by a magnetic force. With solid-state relays (SSR), there are no contacts and switching is totally electronic.
Why are Relays usually in the off position?
Most relays are normally open; that is, the second, larger circuit is in the off position by default. In a normally open relay, power flows through an input circuit, activating an electromagnet. This generates a magnetic field that attracts a contact to join with the second, larger circuit, allowing current to flow through.
Where do you find a relay in a device?
A relay is a simple electromechanical switch made up of an electromagnet and a set of contacts. Relays are found hidden in all sorts of devices.
Why are relays so important for an application?
Even when an application doesn’t specifically require a relay, using one can prove beneficial. Relays can reduce the need for high-amperage wiring and switches, which are expensive and take up space.
What does relay information mean?
1. When relating to a computer or communications, the term relay commonly refers to the act of taking information and passing it to another location. This method of transferring data may be needed either to reach the final destination or help prevent overloading of a single source. For example, when you make a phone call on your smartphone,…
What does it mean to relay a message?
Yes, to “relay” a message is to deliver it. You can say that someone “relayed a speech”, meaning that he stood up and said it, or that he “relayed a letter”, meaning that he delivered the letter or caused it to be delivered.
What does relay means?
relay 1. noun. 1A group of people or animals engaged in a task or activity for a period of time and then replaced by a similar group. 2An electrical device, typically incorporating an electromagnet, which is activated by a current or signal in one circuit to open or close another circuit.
What does relay connection mean?
Relay Connection. A connection used in telegraphy, including a local battery, with a short circuit normally open, but closed by a switch and a sounder or other appliance.