What is ESD

ESD stands for Electristatic Discharge.
This the release of static electricity when two objects come into contact. 
Examples of ESD include the shock we receive when we walk across a carpet and touch a metal doorknob and the static electricity we feel from clothes coming out of the dryer.
These discharges can be in the order of 2000 to 4000 volts though discharges can be smaller in voltage and are not felt.
Although often invisible, this electrostatic discharge generates a considerable amount of heat.
When the ESD transfers onto an electronic device, the intense heat can melt, vaporise, or otherwise damage the intricate parts of the device. This damage can cause it to fail.

ESD damage fall into 2 categories, Catastrophic and Latent

• Catastrophic damage will cause the component to immediately fail and prevent the equipment from working correctly.
• Latent  damage to the component will cause partial degradation and while the component will continue to work its lifespan will be significantly reduced and later failure.

ESD Protection

Antistatic wrist strap

The minimum protection you should use when working on any electronic equipment like your MASSO CNC controller is an anti-static wrist strap.
These are inexpensive and will drain any any static electricity away from your body while you are working on it. 

The crocodile clip end of the wrist strap connects to Earth and it is important to note that the wire that goes between the clip and the strap includes a 1M ohm  resistor. The resistor is included in case you come into contact with a live mains circuit. 

Antistatic Bags

Anti-static bags are used for storing ESD-susceptible electronics. 
When you buy components like motherboards and graphics cards - or any device containing a PCB – they will often arrive in an anti-static bag.
These bags can be silver metallic in appearance or pink in colour and should be labelled as antistatic

If you are sending a board away for repair the board should be placed in an antistatic bag to protect it from static build up during transport and subsequent handling.

Antistatic Mat and workstations

Antistatic mats are placed on work benches and are generally used when working on circuit boards.
They are attached to Earth through a leads with a 1M ohm resistor built into it. This prevents the build up of static on the work bench and will drain away any static that is present. The mat is used in conjunction with a wrist strap worn by the servicing technician.
 

Other types of anti-static mats are floor mats that the prevent static build up by the user standing in the work area and will drain away static electricity.

Antistatic mats are usually used by OEM machine manufactures and when component level repairs are done to circuit boards 

For additional information on ESD and how to protect form it please see  >>>Here<<<