1.0.1 This code was formulated with a view to unify the specifications of instrument power supply design for chemical industry, to promote normalization of instrument power supply engineering design, and to achieve the purpose of advanced technology, economic feasibility, safety and usability.
1.0.2 This code is applicable to the power supply design of measuring and control instrument of chemical plant.
1.0.3 Besides the provisions stipulated in this code, instrument power supply design code shall be in accordance with the requirements of current national standards.
2 Terms and Abbreviations
2.1 Terms
2.1.1 Instrument power supply
DC or AC power supply for measuring and control instruments.
2.1.2 Uninterrupted power supply
Power supply can be continuous a certain serving time after interruption of external power supply, which can be divided into AC uninterrupted power supply and DC uninterrupted power supply.
2.1.3 General power supply
No delay power supply without battery-backed system.
2.1.4 Momentary power failure
The time for momentary interruption of power supply.
2.1.5 Power capacity
Rated value for power output of power supply. Generally, AC power capacity expressed in voltamperes or kilovoltamperes, DC power capacity expressed in emetes of output current.
2.2 Abbreviations
CCS — Compressor Control System
DCS — Distributed Control System
FCS — Fieldbus Control System
PLC — Programmable Logic Controller
SIS — Safety Instrumented System
UPS — Uninterrupted Power Supply
3 Instrument Power Supply Scope, Load Level and Type of Power Supply
3.1 Power supply scope
HG/T 20509-2014 The following standards are cited：
