Advantech ADAM-5511 Manual page 334

• Double isolated cable
Figure 10 is an example of a double isolated cable. The first isolating
layer of spiraled aluminum foil covers the conductors. The second
isolation layer is several bare conductors that spiral and cross over the
first shield layer. This spiraled structure makes an isolated layer for
reducing external noise.
Additionally, follow these tips just for your reference.
• The shield of a cable cannot be used for signal ground. The shield is
designed for carrying noise, so the environment noise will couple
and interfere with your system when you use the shield as signal
ground.
• The higher the density of the shield - the better, especially for
communication network.
• Use double isolated cable for communication network / AI / AO.
• Both sides of shields should be connected to their frame while inside
the device. (for EMI consideration)
• Don't strip off too long of plastic cover for soldering.