1、 Proface

  With the improvement of people's quality of life and the continuous investment in medical reform, it is very important to improve the comfort, economy and reliability of the central air conditioning system in the operating room. Using advanced, practical and reliable programmable controller (PLC) to control is the mainstream of the current central air conditioning control system. This paper introduces the application examples of UniMAT high performance small UN200 PLC and Siemens text display TD400 plus UniMAT extension module in central air conditioning. The superiority and economy of UniMAT high performance small UN200 PLC and extension module in this field are expounded from the aspects of CPU configuration and intelligent hybrid module.

   2. System overview

The automation control system of this project chooses UN 200 PLC series and I/O expansion module. The PLC sampled the temperature and humidity of the return air and supply air in the operating room through the analog input expansion module, controlled the 0-100% opening of the chilled water valve and humidifier through the analog output expansion module, and controlled the electric heating through the digital output. Cold, heating, humidifying and dehumidifying control of operation room's constant temperature and humidity

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3.system configuration

The system adopts CPU and module combination as follows: UN 224+TD400+UN231+UN232. Two RS485 ports are used to connect TD400, two ports are connected to operation room information panel through MODBUS protocol. The actual picture of operation room and information panel is as follows

The overall design logic is: Doctors or nurses through the operating room information panel to control the start and stop of the central air conditioning and adjust the temperature and humidity, when the central air conditioning failure, maintenance personnel can query the alarm content through the local cabinet text display, but also through the PC monitoring computer to query the air conditioning equipment failure. For troubleshooting in time.