ncm   81 / 85



Back page 6 Series NCM Auto Switches Precautions 2 Be sure to read this before handling. Mounting and Adjustment Caution Caution 1. Do not drop or bump. Do not drop, bump or apply excessive impacts (300 m/s2 or more for reed switches and 1000 m/s2 or more for solid state switches) while handling. Although the body of the auto switch may not be damaged, the inside of the auto switch could be damaged and cause a malfunction. 2. Mount auto switches using the proper tightening torque. If an auto switch is tightened beyond the range of tightening torque, the auto switch mounting screws, auto switch mounting brackets or auto switch may be damaged. On the other hand, tightening below the range of tightening torque may allow the auto switch to slip out of position. (Refer to the auto switch mounting instructions for each series for auto switch mounting, moving, and tightening torque, etc.) 3. Do not carry a cylinder by the auto switch lead wires. Never carry a cylinder by its lead wires. This may not only cause broken lead wires, but it may cause internal elements of the auto switch to be damaged by the stress. 4. Fix the auto switch with appropriate screw installed on the switch body. If using other screws, auto switch may be damaged. Warning 8. When multiple auto switches are required “n” indicates the number of auto switch which can be physically mounted. Detection intervals depends on the auto switch mounting structure and set position therefore some required interval and set positions may not be available. 9. Limitations of detectable positioning When using certain mounting brackets, the surface and position where an auto switch can be mounted maybe restricted due to physical interference. For example, when using some bracket types the auto switch cannot be surface mounted at the bottom side of foot bracket, etc. Please select the set position of the auto switch so that it does not interfere with the rear plate of the cylinder. 10. Use the cylinder and auto switch in proper combination. The auto switch is pre-adjusted to activate properly for an autoswitch- capable SMC cylinder. If the auto switch is mounted improperly, used for another brand of cylinder or used after the alternation of the machine installation, the auto switch may not activate properly. 5. Pay attention to the internal voltage drop of the auto switch. 1) Auto switches with an indicator light (Except D-A96, C76) . If auto switches are connected in series as shown below, take note that there will be a large voltage drop because of internal resistance in the light emitting diodes. (Refer to the internal voltage drop in the auto switch specifications.) [The voltage drop will be “n” times larger when “n” auto switches are connected.] Even though an auto switch operates normally, the load may not operate. . In the same way, when operating under a specified voltage, although an auto switch may operate normally, the load may not operate. Therefore, the formula below should be satisfied after confirming the minimum operating voltage of the load. 2) If the internal resistance of a light emitting diode causes a problem, select an auto switch without an indicator light (Model D-A90, C80). 3) Generally, the internal voltage drop will be greater with a 2- wire solid state auto switch than with a reed switch. Take the same precautions as in 1). Also, note that a 12 VDC relay is not applicable. 6. Pay attention to leakage current. With a 2-wire solid state auto switch, current (leakage current) flows to the load to operate the internal circuit even when in the OFF state. If the criteria given in the above formula are not met, it will not reset correctly (stays ON). Use a 3-wire switch if this specification will not be satisfied. Moreover, leakage current flow to the load will be “n” times larger when “n” auto switches are connected in parallel. 7. Ensure sufficient clearance for maintenance activities. When designing an application, be sure to allow sufficient clearance for maintenance and inspections. Operating current of load (OFF condition) > Leakage current Load Supply voltage . Internal voltage > drop of auto switch Minimum operating voltage of load Design and Selection