Application of PLC in automatic control system of diesel generator set

The application of Zhang Jinjiao system in PLC Journal of Hubei Institute of technology in the automatic control of diesel generator, Chen Gang (Department of mechanical engineering, Hubei Institute of technology Hubei Wuhan 430068) introduces the main function design and PLC control of emergency diesel generator unit in the I/O position, focusing on the machine ready to run, starting, stopping, regular self lubrication run the program and the design ideas and methods.
Programmable controller; diesel generator; automatic control; program design of diesel generators as a standby power supply, widely used by the development of Electronic Industry Co. Ltd. in the defense industry, agriculture, commerce and other industries, for the SH series of PLC in the small automatic control system, the design of automatic control system of emergency diesel generator on a single.
The automatic function of 1 diesel generating set is set up, and the power supply can be started in emergency when the power supply is out of power.
2PLC control design according to the automatic function of diesel generator set configuration, the system uses SH-64R1-C programmable controller, 17 point input, 24 point output, the configuration is seen.
High temperature Baoao beat mouse overspeed alarm standby quick stop hydraulic interlocking growth deceleration start stop input pump input electrical heater closing magnetizing oil pump into electric power loss under voltage over high water temperature of mechanical and electrical construction of high temperature oil pressure generator switch manually start the manual switching operation manual stop self reported fight test because the unit is a single emergency reset automated unit, according to the provisions of GB/T4712 "classification of automatic diesel generator set requirements", the unit automation function settings are as follows.
Auto start and load. When the electricity is stopped, the control unit starts automatically, the speed rises, and the power supply is switched on to the load. The process does not exceed 3s. automatic shutdown. After the city electricity is restored to normal, the delay LS is divided into gates, the switch of the city electric switch is switched on, the automatic switch is completed, and then the automatic shutdown of the chiller 5min is controlled. If the power failure occurs during the cooling process, the power supply will automatically switch from the unit to the load automatically. The unit in the operation process, if there is water, oil tea bag fault, sound and light alarm; if low speeding, oil pressure, and alarm the emergency stop; if the abnormal phenomena of overload, short circuit and voltage, sound and light alarm signal and gate.
Pre oiling function. When the unit is in the quasi start state, the automatic pre supply system is put into operation, every 4 S, for the emergency start of the unit at any time.
Test machine function. When the unit is in automatic state continuous outage of more than 15d, the unit can automatically start the test run, check the automatic control function is normal, and the side friction units are fully lubricated by I/O system configuration based on PLC external wiring diagram and the control function, can compile PLC ladder diagram control.
2.2 programming 2.2.1 prepared to run the program is designed to ensure the unit in power cut in 30s after a good start and load power supply unit must be perennial Zhang Jinjiao (1971), female, Hubei Huanggang, lecturer, Hubei Institute of master of engineering, research direction: mechanical design and theory - in preparation for operation. The state includes: 1) diesel engine cooling water and lubricating oil temperature must be maintained in the temperature range of diesel engine with load; 2) timing pre lubrication of diesel engine, the diesel engine rotating parts keep oil film, the unit in the emergency start and rapid loading, no damage to diesel machine.
Prepare the program flowchart as shown.
Preparation program running box. 2.2 unit start-up program design, in the maintenance of the state of operation, the unit from the power outage to the start of the unit, and the main switch to the closing signal to the load power supply, the whole process must be completed within 30s. The working process is as follows: when the city electricity power or low voltage (voltage drop 20%), to confirm 2S diesel engine starting motor start signal, startup speed up to 300r/min, start successful exit signals to start the motor, and speed to the rated speed, and at the same time, the construction unit magnetizing pressure. When the voltage and rotational speed are satisfied, the unit automatically switches on to the load (see).
In the unit start-up program block diagram in the process of starting a startup is not successful for 3 times to start, start when the electromagnet 6S start is not successful, the electromagnet power delay 4S again after the next start. If the 3 start is unsuccessful, the starting delay time is up, then send out the failure to start the sound and light alarm signal and enable the standby machine. 2.2.3 unit shutdown program design, when the city power to restore power supply, there are two kinds of automatic shutdown function for selection. The "automatic" state, city power unit in the confirmation after 10s recovery, automatic gate, switch, power supply automatically by outward two "state, to the operator according to the use of the load, in the need to switch, switch button generator, the load is changed to electric power supply. The above two modes of work in addition to the city power recovery switch mode is not the same, in the switch after the shutdown function is the same, first dropped to 600r/min, no-load running 5min cooler after shutdown (see),.
I pump reset I unit shutdown program block diagram, if in the shutdown process of power supply interruption, return to the starting process directly.
2.2.4 unit regular self lubrication program design of self running time as the case may be, in general, 30min, automatic start unit, idle running 5min, the strip speed 20min, finally the idle running 5min automatic shutdown. If the power loss occurs during the self-test operation, the unit will automatically withdraw from the self lubrication state and enter the normal condition