What Are Analog Input/output & Digital Input/output?

1.	What Are Analog Input/output & Digital Input/output?
Answer» 4-20 mA signals from INSTRUMENT (transmitters) are ANALOG input to control system. 4-20 mA signals to instrument (I/p & electro pneumatic positioner) are analog output from control system. Volt free (24V) contact (NO/NC) by instruments (all type of SWITCHES, ex. Limit SWITCH, press,temp,flow,level switch) are digital input to control system. All powered signals (24V, 48V, 110V….) from system to instruments (SOV) are Digital outputs.

Answer»

4-20 mA signals from INSTRUMENT (transmitters) are ANALOG input to control system.
4-20 mA signals to instrument (I/p & electro pneumatic positioner) are analog output from control system.
Volt free (24V) contact (NO/NC) by instruments (all type of SWITCHES, ex. Limit SWITCH, press,temp,flow,level switch) are digital input to control system.
All powered signals (24V, 48V, 110V….) from system to instruments (SOV) are Digital outputs.

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