Application of Hitachi PLC in central air conditio

Application of Hitachi PLC in central air-conditioning energy-saving system

I. system composition:

this central air-conditioning energy-saving system is mainly composed of touch screen, Hitachi frequency converter, Hitachi PLC, control instruments, temperature sensors and other low-voltage protection and control electrical components. The control system adopts advanced industrial automation, measurement and control, frequency conversion and communication network technology to carry out full-automatic optimization control of the system, effectively reduce energy consumption, reduce labor intensity, improve economic benefits and extend the service life of the equipment. The equipment has complete alarm and protection functions, and the safety factor is greatly improved. The information of heating (refrigeration) equipment is collected, displayed, and processed as the basis for realizing automatic control to avoid dust falling into the machine. The control equipment is in the mode of one drive three control, that is, one frequency converter drives three circulating water pumps (one for use and two for standby). The heating (refrigeration) pipeline temperature sensor collects data on the heating (refrigeration) pipeline temperature and centrally controls the system equipment, More intuitive display of the field system in the operation of various working conditions data, improve the reliability of the system

II. System network structure:

III. system implementation:

u touch screen system interface is shown in figure 1:

figure 1

in the system interface, there is a control system and a data display button

Description:

1: control system button. When clicking the control system button 6, oil gun, enter the control system interface

2: system display button. Click the system display button to enter the data display interface

this is significantly different from the universal insurance that charged a variety of fees in the market before the fee reform

the system control interface is shown in Figure 2

Figure 2

in the main interface, there are four operation indicators, one system start, one system stop, and return to the initial interface buttons

Description:

1: when 1# circulating pump is in power frequency operation, the power frequency operation indicator light of 1# pump flashes

2: when 1# circulating pump is in frequency conversion operation, the frequency conversion operation indicator light of 1# pump flashes

3: when 2# circulating pump is in power frequency operation, the power frequency operation indicator light of 2# pump flashes

4: when the 2# circulating pump is in frequency conversion operation, the 2# pump frequency conversion operation indicator flashes

5: when the system control mode selection switch on the control panel of the control cabinet is in the automatic operation mode, click the system start button and the system will enter the automatic start

6: when the system control mode selector switch of the control panel of the control cabinet turns off the main board is in the automatic operation mode, click the system stop button to stop the system

7: return to the initial interface button. When you click the return to initial interface button, the system will return to the initial interface

u the data display interface is shown in Figure 3

Figure 3

in the data display interface, there is a 1# temperature display, a 2# temperature display, a system temperature target setting, and a button to return to the initial interface

Description:

1: two temperature sensors are set for the return water temperature measurement of the system, and the two temperature sensors are redundant to each other

2:1 # temperature display displays the measured value of 1 # temperature sensor

3:2# temperature display displays the measured value of 2# temperature sensor

4: system temperature target setting, users can set the best return water temperature control target value according to the operating state of the installation system

5: return to the initial interface button. When you click the return to initial interface button, the system will return to the initial interface

IV. conclusion:

the central air conditioning energy-saving control system has been used since the acceptance of Tianjin Armed Police Medical College. The normal operation proves that the design of the whole system is reasonable and advanced; Easy to operate; High reliability; It fully meets the expected requirements of users and achieves the effect of energy saving