Explain how DI cable is different from AI cable
The AI cable is used for traditional Analog HART systems but the DI cable is used for digital Fieldbus systems. AI cable if 24vdc is subject to inductive and capacitive interference from AC equipment. Twisted wire is used to cancel inductive interference. Greater twist per inch provides greater Inductive shielding. Capacitive shielding is provided with a foil covering (gauss law) and a drain wire.
Individual pair shielding and twisted-pair are recommended for AI. For DI multicore cables are also fine.