Showing posts with label relay output. Show all posts
Showing posts with label relay output. Show all posts

Monday, April 5, 2010

Timers and Time Delay Relays


Time Delay Relays
Time Delay Relays all include a combination of a solid state timing circuit and an electromechanical relay output. This combination provides the user with isolation between the operating and load voltages and multiple switching contacts in either SPDT or DPDT forms. Most of the relay contacts are rated 10 amps resistive @ 240 VAC. Many are in the popular octal plug-in package and require the purchase of a socket. Others surface mount with one or two screws and have male 0.25" quick connect terminals. Some are encapsulated to protect the solid state circuitry. A large selection of time delay ranges and adjustment methods are available.

Timing Modules
All popular functions are available in this group of totally solid state timing modules. They contain no moving parts so 100 million operations is typical. They are encapsulated to protect their analog or digital solid state circuitry. A large selection of time delay ranges are available, knob or switch adjustment, or external adjustment, or factory fixed time delays can be ordered.

Some timer and timer delay modes of operation:

DELAY ON MAKE
(On Delay, Delay on Operate, Operate Delay, Prepurge Delay)

OPERATION/TIME DIAGRAM
OPERATION: Upon application of power, the time delay begins. The output is de- energized before and during the time delay. At the end of the time delay, the output is energized (relay is transferred) and remains energized until power is removed.

RESET: Removing power resets the time delay and output.


INTERVAL
(On Interval, Interval On, Pulse Shaping, Bypass Timing)

OPERATION/TIME DIAGRAM
OPERATION:Upon app
lication of power, the time delay begins. The output is energized (relay is transferred) during the time delay. At the end of time delay, the output is de-energized and remains de-energized until power is removed.
RESET: Removing power resets the time delay and the output.

RECYCLING

(Recycle Timing, Repeat Cycle, Duty Cycling)

OPERATION/TIME DIAGRAM (ON TIME FIRST)

OPERATION: Upon application of power, the output is energized (relay is transferred) and the ON time begins. At the end of the ON time, the output de-energizes and the OFF time begins. At the end of the OFF time, the output is energized and the cycle repeats as long as power is applied. The OFF time may be the first delay in some recycling timers.

RESET:
Removing power resets the output and time delays, and returns the sequence to the first delay.

SINGLE SHOT
(One Shot Relay, Single Shot Interval, Pulse Shaping)

OPERATION/TIME DIAGRAM
OPERATION:Power must be applied to the input before and during timing. Upon momentary or maintained closure of the initiate sw
itch (leading edge triggered), the output is energized (relay is transferred) for a measured interval of time. At the end of the delay, the output de-energizes. Opening or reclosing the initiate switch during timing has no effect on the time delay.

RESET:
Reset occurs when the time delay is complete and the initiate switch is opened. Loss of power resets the time delay and output.

DELAY ON BREAK

(Off Delay, Release Delay, Delay on Release, Postpurge Delay)

OPERATION/TIME DIAGRAM


OPERATION:Power must be applied to the input before and during timing. Upon closure of the initiate switch, the output is energized (relay is transferred). The time delay begins when the initiate switch is opened (trailing edge triggered). The output remains energized during timing. At the end of the time delay, the output is de-energized. The output will energize if the initiate switch is closed when power is applied.

RESET:Reclosing the initiate switch during timing resets the time delay. Loss of power resets the time delay and output.


Friday, July 17, 2009

Photo Electric Switches

How do garage doors know when something is in the way?
How do elevators know where to stop?
How does the store keeper know when someone enters a store?
How does a car wash know where the car is?
How does a manufacture count the cans on an assemble line?

Answer: PHOTO ELECTRIC SWITCHES

Photoelectric switches use a light source to detect an object. The switch then changes it's logic or switch to make an action, like an alarm or movement of a device.

The photoelectric switch uses either visible light or infrared light as it's source. The object being sensed should be reflective for a diffuse switch or the use of a reflector is required and the object breaks "the beam" as in an elevator or garage door switch.

A thru beam system utilizes a transmitter and receiver. the Transmitter sends out the light beam and is directed at a receiver unit. Both units need to be powered and interconnected together for the system to work. Advantages are the longest field of view is achieved and the most secure sensing is realized via polarization. The main disadvantage is that each unit must be wired and interconnected together. A "thru beam" system can also be utilized using a reflector. this is called retro-reflective. The retro-reflective system has the advantage over a thru beam of all the logic and power supply being located in one box and one area. It is also more secure like the thru beam system by using polarizing filters that turn the light and only allow the correct "polarization" to be sensed by the receiver. The retro-reflective unit as the receiver and transmitter housed in a single unit. Thru Beam and Retro-reflective systems are used for counting, sorting and sensing the presence of an object or person for safety or security reasons.

The Diffuse system relies on the object being reflective, these are usually used in an industrial setting sensing a product or color code or marking on a product or box. Like the retro-reflective unit the transmitter and receiver are in the same unit. The distance is usually quite short so that the reflected light is able to be sensed. The target does not usually have the reflective qualities of a reflector. A diffuse system is used when a thru beam or retro-reflective cannot be used or when sensing color or a bar code.

All Photo Electric systems need an output to communicate with the PLC or system logic. Most use NPN or PNP logic but some have built in relays (1 amp usually) to give the output signal. The signal can go to a computer, PLC or directly to the system like a motor or contactor or alarm.

ANDERSON-BOLDS CAN HELP WITH ANY APPLICATION FOR PHOTO ELECTRIC SWITCHES.