Showing posts from August, 2016



Art lantern shape PLC Ladder programming and wiring experiment

This article describes an artistic lantern shape PLC ladder programming and wiring experiment described, as follows:

1. Project the necessary equipment, tools, materials


2, the training content:
1, project description
The shape of an art lantern demonstration board as shown in Figure 6, A, B, C, D, E, F, G, H for the eight lights, a ring distribution. The control requirements are as follows:
Will start switch K1 close, eight lighting light at the same time, namely abcdefgh light at the same time a second, then eight lighting according to counter clockwise rotate the light seconds, a bright 1s > b 1s > C bright bright 1s > d 1s > e bright bright 1s > f light 1 second g > bright 1s > h light 1 second; next eight lighting and light at the same time 1: abcdefgh and light 1 second; and eight lighting according to clockwise rotate the light 1 second, namely h bright 1 g > light 1 second > f light 1 second, e light in the 1s > d 1s > C bright …

Application and characteristics of PLC in control system

What is the meaning of the programmable controller:

Acronym PLC programmable controller or PC, is evolved from the early relay logic control system, which constantly absorbing function of the microcomputer technology to growing gradually for complex control tasks.

Since 1836 relay came, people began to use it skillfully wire connected with the switching device, constitute use different logic control or sequential control. So far, the PLC Ladder programming language can also see the shadow of these wires. Until the late 1960s and early 1970s, the advent of programmable controllers, with the rapid development of microelectronics technology, computer technology and data communications technology, as well as the emergence of the microprocessor, PLC products towards small and ultra-small aspects of a leap , and finally to the early PLC from the initial logic control, sequential control, it has developed into a modern PLC logic, timing, counting, memory and arithmetic operations, data process…

PLC ladder programming rules

Although the ladder and relay circuit is similar in structure, elements, symbols and logic control functions and other aspects of phase, but they have many differences, the ladder program has its own rules.

1) Each logical line is always to the left from the bus, and then the contact is connected, the final termination of the coil or the right bus (right bus can not draw). Note: The bus between the left and the coil must be contacts between the coil and the right bus but you can not have any contact.

2) The ladder can contact any series or in parallel, but only in parallel to the relay coil and not in series.

3) the use of contacts unlimited number of times.

4) In general, the same coil can appear only once in the ladder. If in the program, the same coil is used twice or more times, known as "dual-coil output." For the "dual-coil output", some PLC treats it as a syntax error, and definitely not; some will be in front of the PLC output as invalid, only the last valid ou…

PLC ladder programming principles and programming methods

(1) Input / output relay, internal auxiliary relays, timers, counters and other devices of the contact can be used repeatedly, without complex program structure to reduce the use of contacts. (2) Each line ladder left the bus started, the coil terminates at the right bus. Contacts are not on the right side of the coil, as shown below

(3) In addition to stepping procedure, any coils, timers, counters, and other advanced instruction can not be directly connected to the left bus bar.
(4) In the process, does not allow the same number twice coil output (dual coil output). The following ladder is not allowed.

(5) does not allow the bridge circuit.

(6)Shall be prepared by the sequential program from top to bottom, from left to right to prepare the way. To reduce the number of steps in the implementation of the program, the program should be to the left and right big small big small.

(7) as an input device with a normally open contact

(8) PLC programming experience commonly Design
In the tradition…

how to Learn Mitsubishi PLC ladder programming

Beginner PLC ladder programming should be to follow certain rules, and develop good habits. In this paper, Mitsubishi FX series PLC, for example, briefly explain the Mitsubishi PLC ladder programming rules to be followed, allowing users to better understand how to learn to see the Mitsubishi PLC ladder programming, we want to help. One thing to note is that although this article Mitsubishi PLC, for example, but these rules when other PLC program must also be observed.

1, PLC ladder ladder are starting left bus, and finally the right bus (usually can be omitted without painting, painting only left bus). The left side of each line is a combination of contacts, it represents the logical drive coil conditions, and represents the result of logic coil can only be connected on the right bus. Contact can not appear in the right side of the coil. The following figure (a) should read (b):

2, the contact should be plotted on the horizontal line, vertical line should be drawn on the relationship …

The difference between Siemens PLC and Mitsubishi PLC

PLC dealing with for so many years, often met with some beginners asked about the difference between PLC Siemens PLC and Mitsubishi PLC, there are many novice distress to choose which brand to learn, share this article the difference between Siemens PLC and Mitsubishi PLC to everyone.
First, the concept of different programming

Mitsubishi plc is a Japanese brand, intuitive programming, it would be relatively easy to learn, but more instruction. Siemens plc is a German brand, more abstract instruction, learning more difficult, but less instruction, so learning and learning Mitsubishi Siemens cycle is the same.
Personally I think Mitsubishi (high-end Japanese brand) PLC Siemens software behind at least more than five years, and medium-sized Leaving aside, took advantage of the comparative Mitsubishi FX series minicomputers and Siemens S7-200 series, compared with the following Siemens Advantage:
1, Mitsubishi programming software from the early FXGPWIN to recent GX8.0 (I know th…

Turning hydraulic control system


OYES PLC applied using a small wave soldering machine design

I. Overview
Usually large wave soldering machines, production lines, but some customers such as laboratories, schools, small factories need a small lead-free wave soldering machine. Certain electronic equipment factory developed this product, using the Austrian letter OYES series PLC and touch screen. The device requires three temperature control, a total of three PID, the Austrian letter OYES series PLC to achieve 8-channel PID, to meet the equipment requirements. Matched on the touch screen with a high price.
II. Process Description
Dual-wave soldering machine is first necessary to solder temperature, preheat temperature, preheat temperature compensation temperature value added to a total of three temperature settings. When the condition is satisfied, the machine can be produced. The PCB board placed on the track, press the start button, the transmission motor running, start the pump, spray flux, PCB board flux coating is completed, the delay pump stops. When the PCB board…

How to read the S7-1500 CPU running time

Read S7-1500 CPU running time There are many ways, are described below in several ways.

1 reads out the running time by the startup parameters OB1 OB1 start in non-optimized run-time information with the OB1

The startup information passed to the global variable parameters can be read out of the CPU the last scan, minimum, maximum scan time, programming is very convenient.

2 Call RD_SINFO function reads the running time
If you are using an optimized OB1, simplified startup information without running the information shown in Figure 2, you must call the function reads

For example in OB1 RD_SINFO function reads the run time, the program shown in Figure 3. TOP_SI parameters for the current OB1 start information,
Data type SI_classic, need to manually type, ZI1 for the last scan time, ZI2_3 contains the minimum, maximum scan time, low-word minimum scan time,
The high word is the maximum scan time, the examples are transferred to MW10 and MW12. START_UP_SI start to warm start information of…

Through the program determines the touch screen and plc communication failure method

The usual method is to use heartbeat, defined a bool, HMI fixed point set the frequency, PLC receives the point after ON signal is reset. If a period of time, for example, do not receive the points for the ON signal within 5s, it is considered Tongxu interrupted.plc to the memory clock of bytes transmitted to the screen, this screen script-byte value assigned to another address within a plc, plc judge then returned within two bytes of the scan cycle is the same, if the communication is interrupted as described .
For example, look at Figure, follow these steps:1, the establishment of a data block DB1 in the PLC, which provided two switch "PLC seconds switch" and "man-machine switch response"2, human variable connecting these two variables3, the display unit in the property "PLC seconds switch" variable ---- event ---- add value change "is negated bit" so that "in response to human-computer switch" variable with "PLC second…

Delay ON / OFF circuit


Flashing circuit


Three-phase asynchronous motor reversing control circuit


sample PLC circuit diagram


PLC control inverter circuit diagram


PLC conduction delay timer instruction (TON)

When the limit switch 1 is set, the indicator 2 ON 180ms (timer clocked). When the accumulated value of the timer 1 (.ACC) reaches 180, 2 lights off, the indicator 3 is turned on, and remains on until the TON instruction is disabled. If you disconnect the timer is timing the limit switch 1, then turn off light 2.

PLC program sequential logic design method

(1)overview Sequentiallogicdesignmethod is suitable for theoutputsignalsof the statuschange of the PLC hassomechronologicalsituation,wheninprogrammingaccording to drawsequencediagramof the outputsignal,streamliningthestatetransitionsandtransitionconditions,examine the outputandinputandinternalcontacts and therelationship,andmake the appropriatereduction. In General, the sequentiallogicdesignmethodshould beusedwith the experience,orwillprobablymake the logicalrelationshipis toocomplex. (2)sequentiallogicdesignmethodofprogrammingsteps 1)according to the requirements,specificnumber ofinput/outputsignals. 2)clearthetiming

PLC program Transplantation Design Method Programming steps

(1) the analysis of the existingsystemworks Understandtheprocess of thecontrolleddeviceandmechanicalfunctioning,according to relaydiagramanalysisandprincipleofmastercontrolsystem. (2)PLC I/Odistribution Determine the system'sinputandoutputdevices,thePLC I/Oallocation,draw the PLC wiringdiagram. (3)correspond to the establishment of othercomponents OKrelaydiagramrelay,timerelays,auxiliaryrelaysandtimersinthePLC correspondence. (2)and(3)twostepsset uparelaydiagramofallthecomponentsandPLC programmingelementswithintherelationship,for the purposes of transplantationmethod,it is very important.In