ELECTRONIC CONTROL GROUP 2971398 - Caterpillar

Introduction
[Appendix B reproduces Woodward manual 82715.]All electronic equipment contains components that can be damaged, or suffer reduced reliability, from improper handling or incorrect wiring. This manual describes methods of handling electronic equipment and techniques for connecting and checking system wiring. These methods and techniques, if used, will substantially reduce handling damage and in-service failures. Although some types of electronic equipment are more easily damaged by mishandling or incorrect wiring than other types, regular use of these methods and techniques will result in fewer damaged components and increased reliability for all types of electronic equipment.Improper handling (installation, removal, storage, etc.) can cause two types of component failure: immediate failure or eventual failure (decreased reliability). Both of these types of failure, in turn, can be caused by electrostatic discharge, physical damage, or electrical damage.An electrostatic discharge across a device which is sensitive to static electricity usually punctures an insulating layer, causing the device to fail immediately. However, an electrostatic discharge can also weaken an insulating layer without puncturing it, causing eventual premature failure with no immediate malfunction or sign of damage.Rough handling or improper protection during installation, removal, shipping or storage can cause physical damage to a module, a printed circuit board (PCB), or a complete control. Again, the damage may not be apparent immediately, but may cause eventual premature failure.Incorrect system wiring or improper test procedures can electrically damage a control or can cause temporary incorrect operation without actual damage.In order to prevent these types of unnecessary damage to a control, module, or PCB, the following instructions must be followed.Preventing Electrostatic Damage
To effectively reduce damage from electrostatic discharge, all four of the following precautions must be taken:* Reduce the generation of static electricity* Dissipate safely any charges that have built up* Handle equipment correctly* Use protective devicesThe first of these four is the most important because, if no static electricity were generated, the other three precautions would not be necessary. However, since the generation of static electricity is impossible to completely eliminate, all four precautions must be taken to prevent damage from electrostatic discharge.Reduce Static Generation
* Do not wear clothing that readily generates static electricity (synthetic materials generate large amounts of static electricity). Cotton or cotton-blend fabrics, for example, are good because they are not as likely to store electrostatic charges.* Keep all plastic items away from any area where electronic devices are handled. Any plastic item is a potential static generator. This includes candy-wrappers, foam cups, synthetic carpet, foam cushions, etc.* Avoid activities that produce static such as wiping feet or putting on smocks, when in the vicinity of static-sensitive devices.* Maintain as high a humidity as is comfortable and practical.Dissipate Built-Up Charges
* Always discharge any static charge your body might have built up before touching any electronic module, PCB, or control. To do this, touch and hold a grounded metal object for a minimum of two seconds.* When connecting a cable to a control, discharge any charge the cable may have. Touch the cable connector to the