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Precautions for Correct Use of Timers

Operating Time Setting

When setting the operating time, do not turn the setting knob beyond its scale range. For precise time setting, conduct operation tests by adjusting the setting knob.

The accuracy the operating time of the Analog Timer is indicated by the percentage value on the basis of the full-scale time. The absolute fluctuation value will not be improved by changing the time setting. Therefore, when selecting the model, be sure that the application will be able to use a time setting as close as the fullscale time setting of the Timer.

When there are setting changes in the Analog Timers while they are in time-limit operation, the following operation will result.

T: Final time-up time
T1: Time elapsed
T2: New setting
T3: Previous setting

Control Output

Use a load current for the control output relay contact that is below both the rated current and the load indicated for connection to the load circuit. Otherwise the life of the relay contact will be significantly shortened.

For micro-load switching, check the minimum applicable load that is indicated for each product.

The lifetime for control output relay contacts varies greatly with the switching conditions. Be sure to test the contacts in actual operating conditions prior to using them, then use them within a range of switching cycles that will not cause any problems. If a contact is used after its performance has degraded, it may eventually cause insufficient insulation between circuits or burning damage to the relay itself.

The following are correct and incorrect connection examples. Do not wire the Timer like the incorrect example, otherwise a shortcircuit may occasionally be caused by the Timer's internal contacts that will be different to each other in polarity.

For micro-load switching, check the minimum applicable load that is indicated for each product.

Internal circuit

Impose supply voltage on the Timer through a switch or relay contact at one time. Do not impose supply voltage gradually, otherwise the Timer may go into time-up condition or may not be reset.

Be sure that the capacity of the power supply is large enough, otherwise the Timer may not start due to inrush current that may flow for an instant when the Timer is turned ON.

AC power can be applied to the Timer regardless of the polarity of the power supply terminals. When supplying DC power, be careful enough not to make a mistake in polarity.

Faulty operation, abnormal heating, or burning may result from applying a voltage other than the rated voltage, wiring incorrectly, or reversing the polarity when supplying DC power.

Be sure that the ripple rate of DC power supplied to the Timer is within the rated range.

Refer to the following for the ripple rates of typical simple power supplies.

Rectifying methodRipple rate
Single-phase, full-waveApprox. 48%
Three-phase, full-waveApprox. 4%
Three-phase, half-waveApprox. 17%

Note:Refer to the permissible ripple rate of the model to be used.

The Timer can withstand an external impulse voltage with a ±1.2×50-ms standard waveform, imposed between the power supply terminals, which conforms to the Japanese JEC-210 standards. If power surges or noise exists, it may cause damage to internal elements or faulty operation. To prevent this, it is recommended that the waveform be checked, and an appropriate surge absorber be used. The effect of a surge absorber will vary depending on the surge or noise generated, so it must be checked using an actual Timer.

Make sure that no residual voltage or inductive voltage exists when the power is turned OFF.


When using a key switch for setting, do not use your fingernail or an instrument with a sharp point, otherwise the key may be damaged.


When conducting a dielectric test, impulse voltage test, or insulation resistance test between electric circuit and non-currentcarrying metal parts of the Timer mounted to a control panel, be sure to take the following steps. These steps will prevent the internal circuitry of the Timer from damage that may be caused if a machine on the control panel has an improper dielectric strength or insulation resistance.

1. Separate the Timer from the circuitry of the control panel by disconnecting the socket from the Timer or wires.

2.Short-circuit all terminals of the Timer.

If any device with no-contact output, such as a proximity sensor, photoelectric sensor, or SSR, is directly connected to the Timer, current leakage from the device may cause Timer malfunction. Be sure to test the device with the Timer before using the device for actual applications.

Disconnect the wiring before replacing the battery. Touching parts to which a high voltage is applied may result in electric shock.

Before using the Timer to switch inductive loads, be sure to connect a surge absorbing element to the Timer in order to prevent the Timer from malfunction and damage. A diode is an example of a surge absorbing element for DC circuits and a surge absorber is an example of a surge absorbing element for AC circuits.

Examples of Surge Suppressor

Circuit exampleApplicability Features and remarksElement selection
OKLoad impedance must be much smaller than the CR impedance when the Relay operates on an AC voltage. When the contact is open, the current flows through C and R to the inductive load.Use the following as guides for C and R values:
C: 0.5 to 1 μF for a 1-A contact current
R: 0.5 to 1 Ω for 1-V contact voltage However, these values may depend on numerous factors, including the type of load and variations in characteristics. Confirm optimum values experimentally.
Capacitor C suppresses the discharge when the contacts are opened, while the resistor R limits the current applied when the contacts are closed the next time.
Generally, use a capacitor with a dielectric strength of 200 to 300 V. When it is to be used in an AC circuit, use an AC capacitor (with no polarity).
When it is to be used with high DC voltage, if there is any question about the ability to short the arcing of the contacts, it may be more effective to connect the capacitor and resistor across the contacts, rather than across the load.
Perform testing with the actual equipment to determine this.
OKOKThe release time of the contacts will be delayed when a Relay or solenoid is used as the load.
NGOKThe energy stored in a coil (inductive load) reaches the coil as current via the diode connected in parallel with the coil, and is dissipated as Joule heat by the resistance of the inductive load. This type of circuit delays the release time more than the CR type.Use a diode having a reverse breakdown voltage of more than 10 times the circuit voltage, and a forward current rating greater than the load current.
A diode having a reverse breakdown voltage two or three times that of the supply voltage can be used in an electronic circuit where the circuit voltage is not particularly high.
Diode +
Zener diode
NGOKThis circuit effectively shortens release time in applications where the release time of a diode protection circuit is too slow.The breakdown voltage to the Zener diode should be about the same as the supply voltage.
OKOKThis circuit prevents a high voltage from being applied across the contacts by using the constant-voltage characteristic of a varistor.
This circuit also somewhat delays the release time. This circuit is effective if connected across the load when the supply voltage is 24
to 48 V. If the supply voltage is 100 to 240 V, connect the circuit across the contacts.
The cutoff voltage Vc must satisfy the following conditions. For AC, it must be multiplied by √2 Vc > (Supply voltage × 1.5) However, if Vc is set too high, its effectiveness will be reduced because it will fail to cut off high voltages.

Do not use the following types of surge suppressors.

This circuit arrangement is very effective for diminishing sparking (arcing) at the contacts when breaking the circuit. However, since electrical energy is stored in C (capacitor) when the contacts are open, the current from C flows into the contacts when they close. This may lead to contact welding.
This circuit arrangement is very useful for diminishing sparking (arcing) at the contacts when breaking the circuit. However, since the charging current to C flows into the contacts when they are closed, contact welding may occur.

Note:Although it is considered that switching a DC inductive load is more difficult than a resistive load, an appropriate surge suppressor can achieve almost the same characteristics.

When the Timer is reset right after the Timer goes into time-up condition, be sure to provide the Timer with an appropriate circuit configuration considering the resetting time of the Timer so that a sequential error will not result.

Example: ON-delay operation

The Digital Timer uses the constant value read method. Be careful when changing the set value because the output of the Digital Timer will be ON when the set value coincides with the count value.


Surface Mounting

There is no particular restriction on surface mounting directions, but be sure that the Timer is securely mounted horizontally.

P2CF Socket

When mounting the Timer vertically with the P2CF Socket, consider the movable hooks and be sure that there is a 20-mm space on each of the upper and lower parts of the Socket.

Track Mounting (H3CA-FA)

1. Hook portion (A) onto one rail and press the Timer in the (B) direction.

2. When dismounting the Timer, insert a flat-blade screwdriver into portion (C) and remove the Timer.

PL Socket

1. Insert the PL Socket from the panel surface and secure the L-shaped hooks of the Socket with screws.

2. Connect the Timer to the Socket and press the tip of each hook by hand.

PF085A or P2B Socket (1)

1. Mount the Socket to the panel surface and insert the F-shaped hook into the sockets.

2. Connect the Timer to the Socket and press the tip of each hook by hand.

PF85A Socket (2)

1. Secure the Socket to the panel surface with screws and insert the F-shaped hook into the sockets.

2. Connect the Timer to the Socket and press the tip of each hook by hand.

8PFA Socket

Mount a Y92F-42 Base Adapter to the 8PFA Socket.

Fit a socket-type 48-mm x 48-mm Timer from above. The Adapter uses hooks to secure the Timer. It does not serve to convert the wiring.

Flush Mounting

The mounting panel must be 1.0 to 3.2 mm in thickness, and varies with the model. Refer to the precautions for each model for details.

When the Y92F-30 Flush Mounting Adapter is used, insert the Timer into the square hole from the front side of the panel and put on the Flush Mounting Adapter from the rear side of the Timer. Press the Flush Mounting Adapter so that the space between the Flush Mounting Adapter and the panel is reduced as much as possible, and secure the Flush Mounting Adapter with screws.

When multiple Timers are closely mounted vertically, be sure that the molded springs of each Y92F-30 Flush Mounting Adapter are located on the left and right sides.

When multiple Timers are closely mounted horizontally, be sure that the molded springs of each Y92F-30 Flush Mounting Adapter are located on the top and bottom sides.

When using the US08, be sure to use 10.5-mm-dia. max. multiconductor cable or 3-mm-dia. max. insulated stranded wire for wiring.

When the Y92F-40, Y92F-70, Y92F-71, Y92F-73, or Y92F-74 Flush Mounting Adapter is used, just insert the Timer into the square panel hole. If the panel coating is too thick and the hooks do not click, spread open the hooks appropriately to the left and right after inserting the Timer to the hole.

The illustration is an example with the Y92F-70.


Surface Mounting with P2CF

User your thumb to release the hook.

Surface Mounting with PF085A

Use your thumb to release the hook while pressing on the hook with your index finger.

Panel Mounting

Loosen the screws of the Flush Mounting Adapter, spread open the hooks, and remove the Mounting Adapter.

When the Y92F-40, Y92F-70, Y92F-71, Y92F-73, or Y92F-74 Mounting Adapter is used, press the hook inwards with the thumb and index finger of both hands, and press the Timer towards the front side.