A translation methodTranslation method was quite soft in the selected models of PLC devices, instead of the original schematic diagram of relay-contactor control circuit devices will translate relay-contactor control circuit of the PLC ladder program.1. Design procedure2. Design exampleFigure 1 is a translation of the original relay-contactor control circuit using PLC control schematics and ladder … Continue reading PLC software design and design examples

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

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

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

Using two or more normally closed contacts to ensure the coil does not power on function "interlock". Pros and cons of three-phase asynchronous motor control circuit for a typical interlock circuit, as shown in Figure 5-4. KMl and KM2 of which is to control the forward run and reverse operation of AC contactors.Figure 5-4 the … Continue reading Interlocking functions of PLC program of ladder diagram

Its normally open coils continue to stay in power "ON" State function is called locking. As shown in Figure 5-3 the start, maintain and stop the program (stop program for short) is a typical ladder with locking function, X2 and X1 as the starting signal for the stop signal.Figure 5-3 from the stop procedure and … Continue reading Self locking function of PLC ladder diagram

PLC in practical applications often run into two problems: one is the PLC I/O points is not enough and needs to be expanded, however increased I/O points will increase costs; second, the PLC has selected an Extensible I/O points are limited and cannot be increased. Therefore, on the premise of meet the system requirements, the … Continue reading How to reduce PLC outputs