Directive on handling Electrostatic-Sensitive Devices (ESD) 
  E.3 Basic  protective measures against electrostatic discharge 
S7-300 Automation System Module data 
Manual,  08/2006, A5E00105505-04 
E-3 
E.3  E.3 Basic protective measures against electrostatic discharge 
Ensure sufficient grounding 
Make sure all persons, workplaces and packaging are sufficiently grounded when handling 
ESD components. This prevents electrostatic charge. 
Avoid direct contact 
You should only touch ESD components if unavoidable (for example, during maintenance 
work). Handle the modules without touching any chip pins or PCB traces. In this way, the 
discharged energy can not affect the sensitive devices. 
Discharge your body before you start taking any measurements on a module. Do so by 
touching grounded metallic parts. Always use grounded measuring instruments.