OMRON provides a range of Analog Timers and
Digital Timers, as well as Time Switches for 24-hour, weekly, or annual
time control.
Overview of Timers
• What is a Timer?
A timer is a control device that outputs a signal at a preset time after
an input signal is received.
Timer Mechanisms
Settings and Indicators
Example for the H3CR-A
Settings
1. Time setting knob
2. Time unit selector
3. Time range selector
4. Operating mode selector
Note: A variety of time ranges can be set with the H3CR-A using the time
unit selector and time range selector.
Indicators
The pointers on the timer do not move along with time as the hands of a
clock do. Time progression cannot be discerned. Therefore, two operation
indicators are provided on the upper left of the timer to identify the
timer status.
5. Run/Power Indicator (Green)
Run indicator: Indicates whether the time is being clocked or the time has
been reached.
Power indicator: Indicates whether power is being supplied to the timer.
Fundamentally, the indicator will be lit when the power is being supplied
and will flash when the time is being counted.
6. Output Indicator (Orange)
Used to see the status of the output. Lit when a signal is output.
Operating Modes
The operating mode determines the output method to use when the set time
has been reached.
The following four basic operating modes are the most commonly used.
ON-delay Operation
An operation in which a timer receives an input and then the output signal
is output by the switching of the timer contacts after a set time delay is
called "ON-delay operation."
This name is used because there is a delay between when the input signal
is received (i.e., turns ON) and when the output signal is output.
ON-delay operation is the operating mode most often used for automated
machines.
OFF-delay Operation
When you get in your car, the ceiling light turns ON when the door is
opened. The light remains lit for several seconds after you get into the
car and close the door.
The light remains lit to avoid the inconvenience of having to search for
the car keys in the dark.
The ceiling light turns ON at the same time the door switch turns ON by
opening the door. The light remains lit even when the door switch is
turned OFF by closing the door. In other words, the ceiling light turns
OFF after a set time delay. This type of operation, in which the output
turns ON at the same time as the input and then the output turns OFF when
the timer contacts switch after the set time has expired (with the set
time being calculated from when the input turns OFF) is called "OFF-delay
operation."
This name is used because there is a delay between when the input turns
OFF and when the output turns OFF.
Flicker Operation
An operation in which an output repeatedly turns ON and OFF once an input
is received (as shown in the time chart at the left) is called "flicker
operation."
Application: Automatic
Control of Fountains
The water is repeatedly released and stopped at intervals of two minutes.
Interval Operation
An operation in which the input and output turn ON at the same time and
the output turns OFF after a set time (as shown in the time chart at the
left) is called "interval operation."
Applications: Amusement Park Rides
Timer Starting Methods
There are two starting methods for the operating modes.
Example: ON-delay Operation
Signal ON-delay operation:
The time clocking starts when the input section receives an input while
voltage is being applied to the timer power supply section.
Power ON-delay operation:
The time clocking starts when voltage is applied to the timer power supply
section.
Differences between Signal ON-delay Operation and
Power ON-delay Operation
1. Accuracy (See note.):
Operation will not be stable unless a brief period elapses after the power
supply is turned ON to the timing section of the timer.
Power supply start: Operation is unstable because the time
clocking starts at the same time that the power supply turns ON.
Therefore, deviation will occur in the operation time immediately after
starting the Timer.
Signal start: Stable time accuracy is ensured because
voltage is applied to the timer before starting the Timer.
The accuracy of the signal start is generally considered better.
For some models, however, such as the H3CR, there is no change in
accuracy.
Note: Accuracy is the correctness of the time.
2. Terminal Arrangement
Models with a signal start require three external inputs, so they have
many terminals.
Models with a power supply start (H3CR-A8) are the H3CR Timers most often
used for automated machines.
Further Information
of Timers »
Recommended Products
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Multifunction Digital
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H5CX-A /
H5CX-L
DIN 48 × 48-mm Multifunction Digital
Timer/2-stage Digital Timer. |
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Solid-state Timer
H3DK
DIN 22.5-mm-width Solid State Timers
That Easily Fit into Panel Design. |
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Daily Time Switch
H5L
Programming for 24 hours x 7 days
using five switches. |
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