Business
> Industrial Devices
> Automation Controls Top
> FA Sensors & Components
> Timers / Counters / FA Componets
> Counters
> LC2H Total Counter(Discontinued Products)
> Cautions For Use
We are sorry, the products have been discontinued. Please refer to the details of the discontinued products and the recommended substitutes list below.
|
In the circuit that switches an inductive load, a contact failure may occur at a contact point due to surge or inrush current resulting from that switching. Therefore, it is recommended that the following protective circuit be used to protect the contact point.
CR circuit (r: resistor c: capacitor) | |||
---|---|---|---|
Circuit | ![]() |
![]() |
|
Application | AC | * Note: | Available |
DC | Available | Available | |
Features/Others | If the load is a relay or solenoid, the release time lengthens. Effective when connected to both contacts if the power supply voltage is 24 or 48 V and the voltage across the load is 100 to 200 V. | ||
If the load is a timer, leakage current flows through the CR circuit causing faulty operation. Note: If used with AC voltage, be sure the impedance of the load is sufficiently smaller than that of the CR circuit. |
- | ||
Device Selection | As a guide in selecting r and c, c: 0.5 to 1 µF per 1 A contact current r: 0.5 to 1 ohm per 1 V contact voltage Values vary depending on the properties of the load and variations in timer characteristics. Capacitor c acts to suppress the discharge the moment the contacts open. Resistor r acts to limit the current when the power is turned on the next time. Test to confirm. Use a capacitor with a breakdown voltage of 200 to 300 V. Use AC type capacitors (non-polarized) for AC circuits. |
Diode circuit | Varistor circuit | ||
---|---|---|---|
Circuit | ![]() |
![]() |
|
Application | AC | Not Available | Available |
DC | Available | Available | |
Features/Others | The diode connected in parallel causes the energy stored in the coil to flow to the coil in the form of current and dissipates it as joule heat at the resistance component of the inductive load. This circuit further delays the release time compared to the CR circuit. (2 to 5 times the release time listed in the catalog) |
Using the rated voltage characteristics of the varistor, this circuit prevents excessively high voltages from being applied across the contacts. This circuit also slightly delays the release time. Effective when connected to both contacts if the power supply voltage is 24 or 48 V and the voltage across the load is 100 to 200 V. |
|
Device Selection | Use a diode with a reverse breakdown voltage at least 10 times the circuit voltage and a forward current at least as large as the load current. In electronic circuits where the circuit voltages reverse breakdown voltage of about 2 to 3 times the power supply voltage. |
- |
The type of load and its inrush current characteristics, together with the switching frequency are important factors which cause contact welding. Particularly for loads with inrush currents, measure the steady state current and inrush current and use a relay or magnet switch which provides an ample margin of safety. The table below shows the relationship between typical loads and their inrush currents.
Type of load | Inrush current |
---|---|
Resistive load | Steady state current |
Solenoid load | 10 to 20 times the steady state current |
Motor load | 5 to 10 times the steady state current |
Incandescent lamp load | 10 to 15 times the steady state current |
Mercury lamp load | 1 to 3 times the steady state current |
Sodium vapor lamp load | 1 to 3 times the steady state current |
Capacitive load | 20 to 40 times the steady state current |
Transformer load | 5 to 15 times the steady state current |
When you want large load and long life of the counter, do not control the load direct with a timer. When the timer is designed to use a relay or a magnet switch, you can acquire the longer life of the counter.
Since LC4H series counters use a transformerless power supply system, the input equipments must have the power supply transformer in which the secondary side is not grounded with the primary and secondary sides insulated, in order to prevent interference of the power supply circuit when connecting the external input circuit as Fig. A.
Be sure not to use an autotransformer. In case of secondary side grounded or using the autotransformer, this product may be destroyed due to short circuit electrically as Fig. B (1 and 2).
In case of F.G. terminal of equipments such a PLC grounded in secondary side of the transformer, inner circuits of this product and the input equipment may be destroyed due to short circuit electrically as Fig.B (3).
Therefore, use the isolated type counters or do not ground F.G. terminal of the products.
|
Avoid keeping the counter on for a long period of time (over one month). Otherwise heat is generated and accumulated inside the counter, which may deteriorate its electronic parts. If the counter must be kept on for a long period of time, a relay is added. See the circuit diagram below.
|
|
Correctly connect the pins while seeing the pin layout/connection diagram. In particular, the DC type, which has polarities, does not operate with the polarities connected reverse. Any incorrect connection can cause abnormal heating or ignition.
Rectification type | Ripple percentage |
---|---|
Single-phase, full-wave | Approx. 48% |
Three-phase, full-wave | Approx. 4% |
Three-phase, half-wave | Approx. 17% |
For the superimposed surge of power supply, the standard waveform (±1.2×50μs or ±1×40μs) is taken as the standard value for surge-proof voltage.
(The positive and negative voltages are applied each three or five times between the power pins.)
For the standard values for the LC4H type counters, see the respective items in "Caution on usage."
|
If external surge occurs exceeding the specified value, the internal circuit may break down. In this case, use a surge absorption element. The typical surge absorption elements include a varistor, a capacitor, and a diode. If a surge absorption element is used, use an oscilloscope to see whether or not the foreign surge exceeding the specified value appears.
The counter's signal input comes in two ways. One is by opening and closing the input terminal. The other is by applying a specified H-level or L-level voltage to the input terminal.
For an input sensor's residual voltage, input impedance, input voltage level and other signal input conditions, see the ratings for each type of product.
|
In order to increase the reliability in the actual use, check the quality of the counter in the actual usage.
Before using a panel mounting type, please pull and remove the insulation sheet from the side of the product in the direction of the arrow. In consideration that the product might be stored for long periods without being used, an insulation sheet is inserted before shipping. Remove the insulation sheet and press the front reset button.
|
|
The operation part of the panel installation type (installation frame type) is constructed to prevent water from entering the unit and a rubber gasket is provided to prevent water from entering the gap between the unit and the panel cutout. There must be sufficient pressure applied to the rubber gasket to prevent water from entering. Be sure to use the mounting reinforcement screws when installing the mounting frame (ATH3803).
Note: | The one-touch installation type is not waterproof. |
---|
|
|
When installing the mounting frame and rubber gasket please remove the pre-attached o-ring
|
|
Tighten the terminal screws with a torque of 0.8 N·cm or less.
1: | Never apply voltage to the non-voltage input type. This will damage the internal elements. Also, since there is a possibility of erroneous operation, do not connect in parallel the inputs of a non-voltage input type and another counter from a single input signal. |
---|---|
2: | Since the current flow is very small from the count input and reset input terminals ( and on the panel mounting type and terminals (15) to (17) and (26) to (28) on the PC board mounting type) please use relays and switches with high contact reliability. |
3: | When inputting with an open collector of a transistor, use a transistor for small signals in which ICBO is 1 μA or less and always input with no voltage. |
4: | When wiring, try to keep all the input lines to the count and reset inputs as short as possible and avoid running them together with high voltage and power transmission lines or in a power conduit. Also, malfunctions might occur if the floating capacitance of these wires exceeds 500 pF (10 m 32.808 ft for parallel wires of 2 mm2 0.003 in2). When using 2 kHz mode, use with a wiring floating capacitance of 120 pF (3 m 9.843 ft for parallel wires of 2 mm2 0.003 in2). In particular, when using shielded wiring, be careful of the capacitance between wires. |
1: | For external power supply use manganese dioxide or lithium batteries (CR type: 3V). |
---|---|
2: | Always reset after external power is applied and confirm that the display reads "0". |
3: | Make the wiring from the battery to the counter unit as short as absolutely possible. Also, be careful of polarity. |
4: | Calculate battery life with the following formula. t = A / I t: battery life [h] I: LC2H current consumption [mA] A: battery capacity until minimum operation voltage is reached [mAh] |
5: | Hand solder to the lead terminal. Do not dip solder. With the tip of the soldering iron at 300 ℃ 572 ℉ perform soldering within 3 seconds (for 30 to 60 W soldering iron). |
1: | Be aware that applying more than 30 V DC to count input terminals (1) and (2), and reset input terminals (3) and (4) will cause damage to the internal elements. |
---|---|
2: | For external resetting use H level (application of 4.5 to 30 V DC) between reset terminals (3) and (4) of the rear terminals. In this case, connect (+) to terminal 3 and (-) to terminal (4). This is the valid polarity; therefore, the counter will not work if reversed. |
3: | When wiring, try to keep all the input lines to the count and reset inputs as short as possible and avoid running them together with high voltage and power transmission lines or in a power conduit. Also, malfunctions might occur if the floating capacitance of these wires exceeds 500 pF (10 m 32.808 ft for parallel wires of 2 mm2 0.003 in2). |
1: | Use count input terminals (1) and (2) for free voltage input and reset terminals (3) and (4) for non-voltage input. |
---|---|
2: | Be aware that the application of voltage that exceeds the voltage range of the H level to the count input terminal, and the application of voltage to the reset input terminal, can cause damage to the internal elements. |
3: | Since the current flow is very small from reset input terminal (3), please use relays and switches with high contact reliability. |
4: | When inputting a reset with an open collector of a transistor, use a transistor for small signals in which ICBO is 1 μA or less and always input with no voltage. |
5: | To reset externally, short reset input terminals (3) and (4) on the rear. |
6: | Input uses a high impedance circuit; therefore, erroneous operation may occur if the influence of induction voltage is present. If you plan to use wiring for the input signal that is 10 m 32.808 ft or longer (wire capacitance 120 pF/m at normal temperature), we recommend the use of a CR filter or the connection of a bleeder resistor |
|
Notes) | 1. Use the following as a guide for choosing transistors used for input (Tr). Leakage current < 1 μA |
---|---|
2. Use as small a diode (D) as possible in the forward voltage so that the voltage between terminals 3 and 4 during reset input meets the standard value (0.5 V). ( At IF = 20 μA, forward voltage 0.1 and higher.) |
|
Note) | Make sure that H (reset ON) level is at least 4.5V. |
---|
To prevent varying luminance among backlights when using multiple backlight types, please use the same backlight power supply.
|
Requests to customers (Automation Control Components & Industrial Device) [Excluding specific product]
Requests to customers (Automation Control Components & Industrial Device) [For specific product]
Requests to customers (FA Sensors & Components [Excluding motors])
Requests to customers (Dedicated to industrial motors)