Analogue Input & High Level Analogue Input


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What is difference between Analogue Input & High Level Analogue Input? What type of instrument have both AI & HHLAI type of input?
The term high level analog input could very well be a vendor-dependent marketing term.

A couple of vendors call a high level analog input one with only 0/4-20mA or 0/1-5Vdc inputs. While an analog input could be either a universal analog input (T/C, RTD, or mA) or dedicated current, voltage or resistance inputs: thermocouple, resistance, RTD, mV, strain gauge.
Those terms have no standardized meanings. They are marketing terms, so it depends on how the vendor uses the terms.

Honeywell uses the term 'High Level analog input' for 0/4-20mA or 0/1-5Vdc analog inputs. With respect to those levels, thermocouple mV or an RTD circuit are "low level" analog inputs. But you need to inquire of the vendor for confirmation.