Siemens SIPLUS HCS Series Operating Instructions Manual page 263

Electrostatic charging
Any person who is not conductively connected to the electrical potential of the environment
can accumulate an electrostatic charge.
The figure below shows the maximum electrostatic voltage which may build up on a person
coming into contact with the materials indicated. These values correspond to IEC 801-2
specifications.
Figure A-1
Basic protective measures against electrostatic discharge
● Ensure sufficient grounding
When working with electrostatic sensitive devices, make sure that personnel,
workstations and packaging are properly grounded. 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.
SIPLUS HCS4200 PROFINET/PROFIBUS DP
Operating Instructions, 07/2019, A5E35066204A/006
Electrostatic voltages on an operator
Appendix
A.3 ESD guidelines
261