plc program
A, step instructions(1) the STL: step-start instructions(2) RET: step return instructionsSecond, step ladderFigure 1 shows the State transition diagram as shown in Figure 2 can be converted into a step ladderFigure 1Step ladder instruction has the following characteristics:(1) transfer for automatic reset function(2) allows dual output(3) the main control functions
State transition diagram and function chart, it is the State of elements are used to describe the process flow diagram. It is usually composed of the initial state, a series of General State, transfer lines and transfer conditions. Each State provides three functions: drive for loading, specifying conditions of transfer and specify the transfer destination.
Delay connect/disconnect circuit
According to the modular design, modules control functions of the system, in order for the control module design of ladder diagram.For example, in the PC control system of Elevator, the elevator control functions can be divided into: door switch control modules, layer control module, the elevator control module, such as call display and control module. … Continue reading Design method of PLC ladder diagram module
I. structure of the programmable controller1. structure of the PLC include most of the hardware and software. Three-ring between the hardware and control objects:2. first part: is the operating system, using it to manage hardware resources PLC;3. the second ring: is the build system, which had two rings of PLC software system.4. the third ring: … Continue reading Architecture and programming method of PLC
Use a combination of timer and counter the cascade could be expanded delay time, as shown in Figure 5-13. T4 in Figure form a reset timer of the 20s, when X4 connected, T4 coils connected and start delay 20s T4 normally closed contacts disconnect the T4 Timer coil disconnect and reset until the next scan, … Continue reading Delay timer and counter combination of PLC program of ladder diagram
As long as you provide a clock signal as a counter counting input signal, counter can achieve timing function, clock signal multiplied by the cycle counter value is time. Clock signal can be generated by the PLC internal special relay (such as the FX series PLC, M8011, M8012, M8013 and M8014), can also be generated … Continue reading Counters for extended PLC program of ladder diagram
General PLC timer delay time is short, such as the FX series PLC in the 0.1s timer timing range for 0.1~3276.7s, if you need to delay even longer the timer, Cascade using multiple timers can be used to realize the long time delay. Cascade when used for timer, the total time for the timer clock … Continue reading Multiple timer delay procedures of PLC ladder diagram
Most of the timer of the PLC are connected to delay timer, timer start delay after the coil is energized, timing, the timer normally open, normally closed contact closed down. Timer coil power, the contact of the timer reset immediately.As shown in Figure 5-9 to drop the delay program of ladder diagram and sequence diagram. … Continue reading Power off delay the PLC program of ladder diagram
(1) the cycle adjustable pulse generatorsAs shown in Figure 5-6 using a continuous cycle adjustable pulse timers T0. X0 normally open after closing, for the first time when scanning to T0 normally closed contact, which is closed, and T0 the coil after 1s delay T0 normally closed contacts disconnect. T0 normally closed contacts disconnect the … Continue reading Pulse program of the PLC program of ladder diagram
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