ncm   80 / 85



Back page 5 Series NCM Auto Switches Precautions 1 Be sure to read this before handling. Design and Selection Warning 1. Confirm the specifications. Read the specifications carefully and use this product appropriately. The product may be damaged or malfunction if it is used outside the range of specifications for current load, voltage, temperature or impact. 2. Cautions for use in an interlock circuit When an auto switch is used for an interlock signal requiring high reliability, devise a double interlock system to avoid trouble by providing a mechanical protection function, or by also using another switch (sensor) together with the auto switch. Also, perform periodic maintenance and confirm proper operation. 3. Do not make nay modifications (including exchanging the printed circuit boards) to the product. It may cause human injuries and accidents. Auto switch operating range (mm) Time load applied (ms) V (mm/s) = x 1000 Caution 1. Pay attention to the length of time that a switch is ON at an intermediate stroke position. When an auto switch is placed at an intermediate position of the stroke and a load is driven at the time the piston passes, the auto switch will operate, but if the speed is too great the operating time will be shortened and the load may not operate properly. The maximum detectable piston speed is: In cases of high piston speed, the use of an auto switch (G5NTL) with a built-in OFF delay timer (. 200 ms) makes it possible to extend the load operating time. 2. Keep wiring as short as possible. As the length of the wiring to a load gets longer, the rush current at switching ON becomes greater, and this may shorten the product’s life. (The switch will stay ON all the time.) 1) Use a contact protection box when the wire length is 5 m or longer. 2) Even if an auto switch has a built-in contact protection circuit, when the wiring is more than 30 m long, it is not able to adequately absorb the rush current and its life may be reduced. It is again necessary to connect a contact protection box in order to extend its life. Please contact SMC in this case. 3) Although wire length should not affect switch function, use a wire 100 m or shorter. If the wiring is longer it will likely increase noise although the length is less than 100 m. When the wire length is long, we recommend attaching the ferrite core to the both ends of the cable to prevent excess noise. A contact protection box is not required for solid state switches due to their construction. 3. Do not use a load that generates surge voltage. If a surge voltage is generated, the discharge occurs at the contact, possibly resulting in the shortening of product life. If driving a load such as a relay that generates a surge voltage, use an auto switch with built-in contact protection circuit or use a contact protection box. Although a zener diode for surge protection is connected at the output side of a solid state auto switch, damage may still occur if the surge is applied repeatedly. When a load, such as a relay or solenoid which generates surge is directly driven, use a type of switch with a built-in surge absorbing element. 4. Take precautions when multiple cylinders (actuators) are used close together. When multiple auto switch cylinders (actuators) are used in close proximity, magnetic field interference may cause the auto switches to malfunction. Maintain a minimum cylinder separation of 40 mm. (When the allowable interval is specified for each cylinder series, use the indicated value.) The auto switches may malfunction due to the interference from the magnetic fields.