Application of the hottest hybrid PLC in oil burne

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Application of hybrid PLC in fuel oil burner Abstract: This paper introduces the application of hybrid PLC in fuel oil combustion control system. The hybrid PLC can timely adjust the combustion flame condition of the combustor. It can not only monotonically adjust the damper and throttle, but also jointly adjust the damper and throttle to adjust the air and oil in proportion. Because the hybrid PLC has can and RS485 interfaces and supports man-machine interface, the system can be monitored in real time through the upper computer, and the third-party equipment can be connected through the RS485 network

1 introduction

most modern oil burners are automatic control burners. The applicable fuels are diesel, heavy oil, residual oil, and various gas fuels. They can burn oil, gas, and mixed oil and gas. Generally, industrial program controllers, flame detectors, and temperature sensors are used to form an automatic control system to timely adjust the combustion flame status of the burners. We have used Kewei esay series hybrid PLC as the controller of the combustion machine and achieved good results. This paper introduces the mixed PLC burner control system successfully applied in Henan Nanyang Luther road construction machinery factory in March, 2005

2 overview of burner control system

2.1 main technical parameters of burner

1. Oil supply pressure: 1.2-1.8mpa

2. The natural gas pressure is not less than 3000mmh20, and the calorific value is 8500 kcal

3. Adjustment ratio: 1:5

4. The flame speed is about 50-60m/s, and the flame length is about 1 5mm, the flame is in beam shape, the diffusion angle is about 15

5, and the flame temperature is about 1200 ℃

6. Under the rated working condition, the content of C0, CH and flue gas in the flame shall not be greater than 0.1%, and the smoke intensity shall not be higher than ringer Mann level 1

7. The overall noise of the combustion engine is dB

8. The heavy oil temperature in front of the boiler must reach 100 ℃, the residual oil must reach 130 ℃, and the crude oil must reach 80 ℃

2.2 process flow diagram of oil burner

2.3 requirements for control of oil burner

1. The start and stop of the controller are of one button type, with manual and automatic control modes, and can be freely switched

2. The contents of the screen display include: current temperature, air throttle opening, target value display, fault self diagnosis, etc

3. Under the manual control state, the fan, oil pump, large throttle, small throttle, large damper, small damper, electric ignition, solenoid valve and other equipment can be controlled independently

4. The temperature control can ensure that it is within the range of ± 3 ℃ of the target value, and has over temperature alarm protection measures (the alarm temperature can be freely set by the user)

5. The controller is equipped with a computer communication interface, which can be operated online with the asphalt mixer

6. The controller includes temperature, flame and other sensors and their detection systems

3 control system configuration

3.1 description of controller type selection

according to the above requirements, in consideration of cost, performance, user's continuous process improvement and necessary property protection, select a PLC with both switching and analog quantities - easy-m0808r-a0404nb, which can well meet its technical requirements

the hybrid PLC has the following functions:

1), 4-channel analog signal input, the signal type is MV, and 12 bit numerical counting is adopted

2), 4-channel analog signal output, signal type Ma, 12 bit numerical counting

3), 8-point switching value input

4), 8-point switching value output

5), with ladder diagram programming interface, which can be connected to computer or man-machine interface

6). It supports CANbus and RS485 network, and can be used as master or slave of can network or RS485

7). It is connected with the remote module easy ft to realize remote data access

3.2 definition of input and output port

1. E-division thermocouple connection: ax0+, ax0-

2. Oil pressure signal connection: ax1+, ax1-

3. Damper control valve connection: ax2+, ax2- (0-1k feedback) - d11

4. Throttle control valve connection: ax3+, ax3- (0-1k feedback) - d12

5. Fan control connection: y0

6. Oil pump control connection: y1

7 Solenoid valve control connection: y2

8, ignition control connection: y3

promote the transformation and upgrading of tire industry and tire market, green development

9, damper forward rotation: y4

10, damper reverse rotation: y5

11, throttle forward rotation: y6

12, throttle reverse rotation: y7

13, flame detection input: X3 on - on, off - off

14, start: x1

automobile industry and aircraft manufacturing have always been the most important industrial sectors in the UK.115 Stop: x2

16, manual/automatic: x0

17, damper plus: x4

18, damper minus x5

19, throttle plus x6

20, throttle minus x7

3.3 hardware wiring diagram

3.4 software implementation description

3.4.1 automatic part:

in combination with process requirements, the main program adopts step-by-step instruction programming to realize the process flow to automatically complete the whole combustion process as required

3.4.2 manual part:

it is used for equipment commissioning and emergency treatment, and is written with general ladder diagram instructions

3.4.3 relevant subroutine part:

temperature transformation subroutine

output conversion subroutine

ad value sampling filter subroutine

temperature control automatic adjustment subroutine

3.4.4 man machine interface program and function

manual and automatic adjustment

parameter setting

display of temperature and pressure signals

burner process flow display

alarm indication, etc.

note: the program is omitted here, and those interested in the program can call for it

4. System features

4.1 strong universality, low development cost and good process confidentiality. The hybrid PLC can process both switching signals and analog signals, which saves unnecessary expenses and greatly reduces the cost. At the same time, it also has good process confidentiality. Users can encrypt and write their own programs, and intellectual property rights are protected

4.2 powerful networking function

4.2.1 the hybrid PLC selects CANbus as the current cost field group bus to reduce the cost. All can network slave devices developed according to this standard can be connected to the can network with easy as the master station, so as to have the value-added services brought by the can network, such as ladder diagram programming with platform nodes, and sending product information to the man-machine interface

4.2.2 another communication network of hybrid PLC is RS485 network, and its physical interface is serial port 1. On serial port 1, a subset of Mitsubishi FX2N computer link format 1 protocol is loaded under the operation mode, that is, only data register D is read and written. However, embedded PLC can be both the master of the protocol and the slave of the internal protocol for the sustainable development of the enterprise. The RS485 network communication speed is specified as 9600 BPs, but the setting of master and slave stations, the setting of communication message number and message length, the control of message sending frequency and other network communication controls are completed by ladder diagram

5. Conclusion

the hybrid PLC used as the combustion controller provides the following control modes: manual control, automatic control, damper section fire control, variable frequency section fire control, damper adjustment proportion control, variable frequency adjustment proportion control, touch screen digital variable frequency proportion control, which can realize the functions of automatic ignition, flameout protection and automatic fire adjustment, and has the characteristics of energy saving, safety, stability and reliability, network interconnection, etc. (end)

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