Tag Archives: plc courses

What is the meaning of PLC constant?

PLC constant is that we set a good time in the program, after running in the process does not change the number, as we set a timer time is 10s, then 10 is constant, relatively constant is variable, The variable can change the value.

For example, we can set the time of a certain timer to be the PLC’s memory channel DM100, and then we can give the DM100 different values during the running process. The constant has a decimal number (that is, every ten in one), and the binary number (the two used in the machine) is octal, hexadecimal, etc. There are 32 more digits you should ask, like 1111 is 4 digits.

What is the meaning of Mitsubishi PLC constant H?

The Mitsubishi PLC constant H represents a hexadecimal number and is mainly used to indicate the operational value of the application function instruction.

K is a symbol indicating a decimal integer. It is mainly used to specify the set value of the timer or counter and the value in the operand of the application function instruction. H is a hexadecimal number, which is mainly used to indicate the operation value of the application function instruction. For example, 20 is expressed as K20 in decimal and H14 in hexadecimal.

Omron PLC data type

Omron PLC data type

Address of a binary bit – a logical Boolean on or off state. This type is typically used for contacts or coils.

This is a special data type, for backward compatibility. It is an address (non-bit) to data of any type (unsigned or signed, one or more words), so can be used in place of any of the above data-types except NUMBER and BOOL. The data type is weak, and so checking is limited (e.g. CX-Programmer cannot check if the address is being used for BCD or binary values).

Address of a signed, double binary word.

Address of a signed, single binary word.

Address of a signed, quad binary word.

A literal numeric value. Not an address. The value can be signed, or floating point. NUMBERs are used for any literal value or for timer/counter identifiers (in this case, only unsigned integer values are allowed). Floating point values are only suitable within IEEE REAL type operands.

Note: when used as BCD number operands, the value is treated as a hexadecimal value (e.g. using a NUMBER E234Eis equivalent to typing E1234Eas the operand, so that the decimal interpretation is made of the value). The value of a NUMBER data type is assumed to be decimal, unless it is prefixed with ‘#’ for a hexadecimal value.

Address of a double word floating point value (IEEE format – use the UDINT type for the BCD, FDIV format).

Address of a long word floating point value (IEEE format – use the ULINT type for the BCD format).

Address of an unsigned, double binary word.

Address of an unsigned, double BCD word.

Address of an unsigned, single binary word.

Address of an unsigned, single BCD word

Address of an unsigned, quad binary word.

Address of an unsigned, quad BCD word.

Address of a bit string of 16 bits.

Address of a bit string of 32 bits.

Address of a bit string of 64 bits.

Siemens S7-200PLC Counter Area (C)

In the S7-200 CPU, the counter for the accumulated number of pulses from the input terminal or internal components sent. It has up counter, down counter and up / down counter 3 types.
Due to limitations counter frequency scan cycle, when the need for high-frequency signal can be counted when a high frequency counter (HSC).
There are two forms of addressing the counter.
● the current value of addressing: 16-bit signed integer stores the accumulated number of pulses.
● Counter-bit addressing: a comparison result based on the current value and the preset value is set or reset. Like timers, both addressing ways to use the same format, namely C + counter number. For example: C0

Siemens S7-200 PLC local variable storage area (L)

Local variables and variable storage memory is very similar, the main difference is that the local variables memory is partially valid, the variable memory is globally effective.
Globally effective refer to the same memory can be used by any program (such as main program, an interrupt routine or subroutine) access to local storage areas and effective means associated with a particular program.
Local variables memory often used as a memory for temporary data transfer function or subroutine. Can be bit, byte, word, or double word to access the data storage area of the local variables.
Bit: L [byte address]. [Bit Address] L0. 5
Byte, word or double word: L [length] [starting byte address] LB34 LW20 LD4

Siemens S7-200 series PLC analog input (A1)

S7-200 converts an analog value (such as temperature or voltage) into a word-length (16-bit) digital value.
You can use the area identifier (AI), the data length (W) and the starting byte address to access these values.
Since analog inputs of a word, and the even-number bytes (such as 0,2,4) started, it must be an even number byte addresses (such as AIW0, AIW2, AIW4) to access these values. Analog input value is read-only data, the actual accuracy analog conversion is 12.
Format: AQW [starting byte address] AIW4

What is the difference S7-200 PLC system operating temperature

s7-200 PLC work at minus 20 degrees?
S7-200 working environment requirements:
0 ° C-55 ° C, horizontal installation
0 ° C-45 ° C, vertical mounting
95% relative humidity, non-condensing
Siemens also offers a wide temperature range S7-200 product (SIPLUS S7-200):
Operating temperature range: -25 ° C- + 70 ° C
Relative Humidity: 55 ° C at 98%, 70 ° C 45%
Other parameters of the same product with the ordinary S7-200

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 traditional relay – contactor control diagram and typical PLC based control circuit, based on the experience accumulated translation, revised and improved to give final control procedures.

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 as shown in (a) contacts and other contacts between the X005 does not recognize. For such a bridge circuit should be from left to right, top to bottom, the principle of one-way, single draw all the way. FIG. (B) below:

3, parallel block series should contact many of the path on the ladder to the left (left and right light-weight principle); parallel blocks in series, parallel path should be more contacts on the top of the ladder (top heavy the rules). To do so, the program is simple, thus reducing scan time directive, which is particularly important for some large programs. As shown below:

4, not to use double-coil output. If the same ladder, more than two coils of the same component or twice, then known as the reuse or dual-coil output coil. Usually one of the dual-coil output ladder for beginners easy to commit wrong. In the double-coil output, only the last coil to be effective, and front coil is invalid. This is caused by the PLC scan feature of the decision.
PLC uses the CPU work cycle scan. Generally consists of five phases (as shown): internal diagnostics and treatment, and communication peripherals, input sample, the user program execution and output refresh. When the mode switch is in STOP, before performing only two phases: internal diagnostics and treatment, and communications peripherals.

1, the input sampling stage
PLC sequential reads the state of each input, and the input image is stored in the register we call the internal unit. When entering the program execution stage, such as the input changes state corresponding cell information input image area does not change with it, only the next input sampling phase of the scan cycle, the input image area corresponding to the cell information will change. Therefore, PLC will be overlooked pulse variation is less than the amount of the scan cycle switch input.
2, program execution stage
PLC from the program step 0, beginning with the first following the first left and right sequence scans the user program and logical operations. PLC input image by content area for logical operations, and the result is written to the output image area, rather than directly to the output terminals.
3, the output refresh period
PLC output terminal changes depending on the content of the output image area. This is the actual output of the PLC.
Above brief description of the working principle of PLC, the following examples explain why we then to write ladder program should not be repeated using a coil. As shown below, when the reset input is sampled input image area X001 = ON, X002 = OFF, Y003-ON, Y004 = ON is actually written to the output image area. But to continue down, because X002 = OFF, so Y003 = OFF, this is after the result has been written to the output image area, change the original state of Y003. Therefore, the output refresh period, the actual external output Y003 = OFF, Y004 = ON. Many newcomers to come across such a problem, why X001 has been closed, and no output Y003 it? Logic is wrong. In fact, because the use of double coil caused.

Note: we are talking about is not (should not) use dual-coil, double coils are not absolutely prohibited, in some special occasions can also use double-coil, then you will need a more extensive programming the experience and skills. Let’s talk about this. But still do not risk it for beginners. In fact, it can be seen from the above examples, the reason will result in Reuse coil output Y003 confusion is due to the reason the program is executed sequentially from top to bottom caused. But if we can change the order of program execution, at any time to ensure that the two coils is only one logical drive occurs, you can use double-coil. The most common method is to use a jump instruction

Program Analysis: M0 closed, the program jumps to at P0 (no X001 statement), M0 normally closed off, CJ P1 does not occur, the next statement. In this case, Y003 to X002 state drive. State M0 disconnected, according to the order of execution of T003 X001 is driven M0 NC closed skip P1 state by X003 to drive on Y004, which skips the X002 drive Y003 statements. Visible at the same time, Y003 drive only one can occur. In this case, the use of double-coil is possible.
But in ladder programming, we still have to try to avoid the use of dual-coil, and the introduction of auxiliary relay is a commonly used method. As shown below:

Figure (b),, X001 and X002 contact control auxiliary relay M000, X003 ~ X005 contact control auxiliary relay M001, and then by two relays M000, M001 parallel combination of contacts to control the coil Y000. Such logic has not changed, yet the double coil into a single coil.

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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.

Ladder Diagram

STEP7-Mirco/WIN software project management

1 print
(1.) printing method of program and project documents

Print program and project documents in the following way:
Click the print button.
Select the menu command file then print.
Press the CTRL + p shortcut key combination.

(2). network and print a single item
Following a single block printed a series of network, or from a single symbol table or figure printed a series of rows:

1, select the appropriate check box, and use the range field specifies the print element.

2, select a range of text, the network, or line and select print. You should check the following items: the print order/ write correctly in the frame Editor; scope items box, select the correct POU (if applicable), POU scope free right of the entry box radio button; scope shows the correct number in the entry box.

2 replication project

Can be copied in STEP 7-Micro/WIN project 32: text, instruction or data domain, a single network, multiple adjacent networks, POU in all networks, rows or columns, or the entire state diagram, symbol table rows or columns, or the entire symbol table, a data block. But not copies or multiple noncontiguous networks. Cannot bulk copy data from one local variable table and paste it to another local variable tables, readonly l memory assignment for each table must be unique.

Cut, copy, or delete the network as a whole in LAD and FBD program, you must place the cursor in the network header.

3 importing files

From STEP 7-Micro/WIN 32, an importer, you can use the import command to import ASCII text files. The import command does not allow you to import the data. Open a new or existing projects, you can use file import command.

If you import OB1 (main program), will delete all existing POU. Then, as OB1 and as ASCII text files, all part of routine or interrupt program ASCII data creates an organizational unit.
If you import only subroutines and interrupts the program (not defined in the ASCII text file of the main program), POU defined in the ASCII text file will replace all existing corresponding number from STEP 7-Micro/WIN project 32 POU (if STEP 7-Micro/WIN project 32 is not empty). Existing STEP 7-Micro/WIN project 32 main program and is not defined in the ASCII text file of all STEP 7-Micro/WIN 32 POU is retained.

If the STEP 7-Micro/WIN 32 projects may include OB1 and SUB1, SUB3 and SUB5, and from an ASCII text file import, SUB2, SUB3 SUB4. Final project: OB1 (from STEP 7-Micro/WIN project 32), SUB1 (from STEP 7-Micro/WIN project 32), SUB2 (from ASCII text file), SUB3 (from ASCII text file), the SUB4 (from ASCII text file), SUB5 (from STEP 7-Micro/WIN 32 projects).

4 exporting files

Editor for the export program to STEP beyond 7-Micro/WIN 32, you can use the export command to create the ASCII text file. The default file name extension for awl , you can specify any file name. Program only successfully compile can execute export operations. Export command does not allow you to export data. Open a new or old projects to use the export function.

With the export command by the following methods to export existing POU (main program, subroutine, and interrupt routines)

If you export a OB1 (main program), all existing project POU as ASCII text files, and exporting.

Export routine or interrupt routines, currently open for editing a single POU exported as ASCII text files.

Siemens S7-200 PLC high-speed counter instruction Initialization

High speed counter instruction is initialized as follows:

(1) first scans through a special internal memory scanning cycle SM0.1 to call a subroutine to complete initialization. Because the use of subroutines, in subsequent scans, no need to call this subroutine, to reduce the scanning time, make the program better.

(2) in initial of of child program in the, according to hope of control set control word (SMB37, and SMB47, and SMB137, and SMB147, and SMB157), as set SMB47=16#F8, is for: allows count, writes new current value, writes new pre reset value, update count direction for added count, if for orthogonal count set for 4x, reset and up moving set for high level effective.

(3) execute HDEF instructions, sets the number of HSC (0-5), set the work mode (0-11). HSC‘s number is set to 1, enter work mode is set to 11, are both orthogonal count reset and start mode.

(4) the new current value current value write 32 bit registers (SMD38,SMD48,SMD58, SMD138, SMD148, SMD158). Write 0, clears the current value realized by MOVD instructions 0,SMD48.

(5) with a new preset value preset value write 32 bit registers (SMD42, SMD52, SMD62, SMD142, SMD152, SMD162). If execution of the MOVD instructions 1000,SMD52, set the preset value is 1000. If written to the preset value is 16#00, then high speed counter in the off position.

(6) in order to capture the current value equal to the preset value of events, conditional CV=PV interrupt events (event 13) associated with a break.

(7) in order to capture the change counting direction will change interrupt event (event 14) associated with a break.

(8) in order to capture the external reset, reset the external interrupt event (event 15) associated with a break.

(9) perform a global interrupt enable directive (ENI) allow HSC interrupted.

(10) S7-200 programming for the high speed counter HSC instruction is executed.

(11) the end subroutine.

Siemens S7 200 PLC high-speed counter (HC)

        High-speed counter for frequencies above scan cycle external signals are counted, using a dedicated high-speed counter terminals of the host to receive these high-speed signals. High-speed counter is a high-speed event counting, it is independent of the CPU scan, the data for the current value of high-speed 32-bit signed calculator.


HC [high-speed counter number] For example: HC1

S7-200 series PLC compare instruction

      SIEMENS S7-200 programming software in the STEP-7, a special compare instruction: IN1 and IN2 to compare the two data types can be B, I (W), D, R, that is, byte, word, integer, double word integers and real numbers; you can also have other comparative:>, <, ≥, ≤, , and so on. When the comparison satisfies the equation, then the contact is closed.

     LMODSOFT control and instruction: in LMODSOFT, there is no direct comparison of the number of instructions, but SUB instruction can be achieved by an integer comparison function three state output of the subtraction function after it.
If corresponds LMODSOFT the SUB instruction, should be in the STEP-7 instruction in three comparisons:> =, <, respectively corresponding to the three output SUB instruction; even if the corresponding ≥, ≤, or <>, according to different combinations of three outputs SUB instruction, may find the corresponding comparison instruction.

                                 For example: ① (30007)> (40030)
② (30007) = (40030)
③ (30007) <(40030)
① + ② (30007) ≥
② + ③ (30007) ≤ (40030)
① + ③ (30007) (40030)

S7-200 PLC high speed counter instructions

(1) each counter has a 32-bit high-speed current values of preset and a 32-bit value, current value, and default value for the signed integer values. To set the new high speed counter current and new preset values, you must set the control byte (table 6-7), making it the fifth and sixth bit is 1, allow update the preset value and the current value, the new current value and writes a new preset value special flag store. And then do the HSC instruction, set the new value to the high speed counter
Besides control bytes as well as the new preset value and the current value of bytes, but can also use data type HC (high-speed counter current value) and counter number (0, 1, 2, 3, 4, or 5) read each high speed counter‘s current value. Therefore, the read operation can be directly read the current value, but only with the HSC directives to perform write operations.
(2) before performing a HDEF instructions, high speed counter control byte bit must be set into the State, or else will use the default settings. Default settings: reset and start input active high, quadrature counting rate selection 4x mode. After performing a HDEF instruction, you can no longer change the counter sets, unless the CPU enters the stop mode.
(3) when you perform a HSC instruction, related to the CPU and check the control bytes current and preset values.

S7-200 PLC type of interrupt sources

S7-200 sets the interrupt function for real-time control, high-speed processing, communications and control of complex and special tasks such as network. Disruption is to terminate the currently running program, to carry out immediate interrupt service program has been developed in response to signals, is complete and then return terminated the program and continue to run.
Interrupt sources of interrupt request is issued, also known as interrupt event. For ease of identification, the system gives each interrupt source is assigned a number, known as an interrupt event. S7-200 series programmable controllers up to 34 interrupt sources, divided into three categories: loss of communication, time base and input/output interrupt interrupts.

(1) communications
In the free port mode, users can programmatically set the baud rate, parity, and the communication protocol and other parameters. User programmatic control of communication port event for loss of communication.

(2) the I/O interrupts
I/O interrupt include external input rising/falling edge interrupt, high speed and high speed pulse output interruption of their counter. S7-200 input (I0.0, I0.1, I0.2, or I0.3) rising/falling edge interrupts. These entry points are used to capture events that occur must be dealt with immediately. High-speed digital high speed counter in the counter running events that occur when the real-time response, including the current interrupts that occur when the value is equal to the default value, change counting direction when interrupted or counter external reset interrupt. Pulse output interrupt is scheduled to be completed number of pulse output and disruption.

(3) the time base break
Includes timer interrupt and timer T32/T96 interruption of their timing. A periodic timer interrupt is used to support activities. From 1 MS to 255 Ms cycle time, the time base is 1 Ms. Using the timer interrupt 0, must write a cycle time SMB34; using the timer interrupt 1, must be written in SMB35 cycle time. On the timer interrupt event will break the connection, if the timer interrupt allowed, you set start time, whenever the time value is reached, the interrupt programs. Timer interrupt can be used for analog input is sampled or regular PID loop. T32/T96 finger allows to set the time interval of the timer interrupts. Such disruption can only use timebase as 1ms timer T32/T96 component. When interrupts are enabled, current value equal to the preset value, the normal 1 millisecond timer S7-200 perform in the process of updating, the interrupt program execution.

S7-200PLC structure

1. Status indicator (LED) displays the CPU‘s job status.
SF–System Fault (System error)
2. Memory cards can be inserted memory card
3. Communication interface can be connected RS-485 communications cable
_ EMBED PBrush ___
4. Top cover bottom for output terminals and the PLC power supply terminal. Running from the top of the output terminal terminal block cover beneath a row of led displays, ON state of indicator lights.
_ EMBED PBrush ___
5. Below the bottom terminal cover for input and sensor power supply terminals. Running from the bottom terminal of input terminal cover above a row of led displays, ON state of indicator lights.
6. Front cover the following run, stop switch and interface module socket. Will switch to the stop position, the PLC is stopped, you can write the program. Will switch to the run position, PLC is running, you cannot write the program. To switch to the monitor (Term), you can run the program, and can also monitor the status of programs run. Interface socket for connecting expansion modules, implement I/O extension.

Siemens PLC interface module

S7-200 digital I/O module interface module, analog I/O modules and communication modules. These modules are introduced below.
(A) the digital I/O module
Digital I/O module is native integration to solve digital input/output points can not meet the need to use extension modules. S7-200PLC currently offers 3 categories in total, total 9 digital I/O module.
1. EM221 digital input extension module
8DI,DC24V (DC input)
2. EM222 digital output expansion module
8DO,DC24V (DC)
8DO,Relay (DC24V/AC24~230V) (relay output)
3. EM223 digital mix module
4DI(DC24V),4DO(Relay 2A)
8DI(DC24V),8DO(Relay 2A)
16DI(DC24V),16DO(Relay 2A)
(B) the analog I/O modules
Analog I/O module provides analog input and analog output extension. S7-200 analog expansion module with greater fitness and can be directly connected to the sensor, and a great deal of flexibility, and ease of installation.
1. EM231 analog input module
4AI (voltage or current) input signal ranges set by the SW1, SW2 and SW3.
2. EM232 analog output module
2AO (voltage or current)
3. EM235 analog mixed modules
4AI (voltage or current), the range set by the SW1~SW6
1AO (voltage or current)
(C) communication module
S7-200 series PLC in addition to CPU226 native has two communication ports other than, the other is in the integrated communications, communications with the RS-485 bus. In addition, the PLC can also access communication module in order to expand the number of its interface and the networking capabilities.
1. EM277 module
EM277 module PROFIBUS-DP Slave module also supports MPI from outbound traffic;
2. EM241: modem (Modem) communications module
3. CP243-1: industrial Ethernet communication module;
4. CP243-1 IT: industrial Ethernet communication module, while providing IT application such as Web/E-mail;
5. CP243-2:AS-master module can be connected to up to 62 as-I slave station.
S7-200PLC configuration is made up of S7-200CPU and the extension modules.

Structure of the Siemens S7 PLC timer

S7 clock time by time and time value is composed of two parts, time is equal to the product of time and timing values. When the timer runs, the timing values continue to lose 1, until reduced to 0, down to 0 means that the time to. Time after time to cause the timer contacts.

Timer No. 0 on the 11th store timing values in BCD code format, three-bit BCD code range is 0~999. 12th, 13 storage time base in binary format.

As can be seen from the following table: small time base timer resolution high but narrow time range; base at low resolution, wide timing range.
Time base binary base resolution timing range
10 s 00 0.01 s 10ms to 9s_990ms
100ms 0l 0.1 s 100ms to 1m_39s_900ms
1 s to 10 1S 1S 16m_39s
10 s 11 10 s 10s to 2h_46m_30s

When the timer starts, the accumulator 1 lowWord content is loaded by as time timing. The process is controlled automatically by the operating system, the user simply accumulators mount a different number, you can set the time you want.
Recommend the following intuitive syntax:
L W#16# txyz
Where: t,x,y,z is a decimal number;
T = time base, values of 0,1,2,3 to represent the time base for 10ms, 100ms, 1s, 10s.
XYZ= timing values, value range: 1 to 999.
Can also be used directly in S5, mounted timing values time notation, for example:
L S5T# aH_bbM_ccS_dddMS
Where: a= hours, BB= minutes, CC= seconds, DDD= milliseconds.
Range: 1MS to 2H_46M_30S; at this point, the time base is automatically selected, the principle is: according to the scheduled time can meet the requirements of timing range minimum time base.
S7-300 offers a variety of forms of timer: pulse timer (SP), extended timer (SE), ondelay timer (SD), connected with keep delay timer (SS) and power off delay timer (SF).

Siemens S7 series PLC types And application software

Germany Siemens (SIEMENS) produced by application of programmable logic controller in China is quite extensive, in the fields of metallurgy, chemical industry, printing production line are used. Siemens (SIEMENS) PLC of company products including LOGO,S7-200,S7-300,S7-400, industrial network, HMI HMI, industrial control software.
PLC Siemens S7 series of small size, speed, standardization, network communication capabilities, more powerful, more reliable. S7 PLC products can be divided into micro-PLC (S7-200), PLC small-scale performance requirements (such as S7-300) and PLC, high performance requirements (such as S7-400).

S7-200 PLC is the ultra small PLC, it applies to all walks of life, on various occasions in the detection, measurement and control. Power of S7-200 PLC to run stand-alone or connected network can achieve complex control functions.
S7-200 PLC offers 4 different basic models and 8 types of CPU available.

S7-300 is a modular mini PLC system, with moderate performance requirements of the application. Various combinations of separate modules for a wide range of different requirements of the system. Compared with the S7-200 PLC, S7-300 PLC has a modular structure with high-speed (0.6-0.1US) speed of instructions using floating point arithmetic more effectively to achieve a more complex arithmetic; a user-friendly software tool with a standard user interface for all modules for parameter assignment; within a convenient way of human-machine interface has been integrated in the S7-300 operating system, interactive programming requirements significantly reduced. SIMATIC human machine interface (HMI) getting data from S7-300, S7-300 according to the refresh rate of the data specified by the user. S7-300 operating system automatically to processing data of transfer; CPU of intelligent of of diagnosis system continuous monitoring system of function whether normal, and records errors and special system event (for example: timeout, module replaced, and so on); multilevel password protection can using user height, and effective to protection its technology confidential, prevent without allows of copy and modified; S7-300 PLC has operation way select switch, operation way select switch like key as can pulled out, dang key pulled out Shi, You can’t change mode of operation, thus preventing illegal delete or overwrite the user program.

With powerful communication capabilities, S7-300 PLC programming software Step7 user interface provides communication configuration feature, which makes configuration easy and simple. S7-300 PLC has a variety of different communication interfaces, and through a variety of communications processors to connect the as-I bus interface bus and industrial Ethernet system serial communications processor is used to connect to a point-to-point communication system multi-point interface (MPI) integrated in the CPU, used to connect a programming device, PC, human machine interface systems and other automated control systems such as SIMATIC S7/M7/C7.

S7-400 PLC is used in high-end performance range of programmable controllers.
S7-300 modular PLC fanless design, durable and reliable, while a variety of levels (functional escalation) of the CPU, and is equipped with a variety of templates for common functionality, which enables the user to combine different dedicated systems as needed. When expansion or upgrade of control system, as long as appropriate to add the template, will be able to upgrade the system to fully meet your needs.

4. Industrial communication networks
Communications network is the backbone of automation systems, Siemens totally integrated automation platform provides the network from the control level to the field-level consistency newsletters SIMATIC NET” is the General term for all network series, they can be in different parts of the plant, different station and Exchange data through different levels of automation, standard interfaces and are fully compatible with each other.

5. Human-machine interface (HMI) hardware
Use with PLC HMI hardware, provide data, graphics and event displays for users, mainly text operator panel TD200 (Chinese), PO3,OP7,OP17; OP27,OP37 graphics/text operator panel, touchscreen operator panel TP7,TP27/37,TP17A/B; PC670 SIMATIC Panel. Personal computer (PC) can also be used as HMI hardware. HMI Hardware require software (such as a ProTool) configuration to use with PLC.

6.SIMATIC, S7 software
Siemens industrial software is divided into three different categories:
(1) programming and engineering tools include all programming and engineering tools based on PLC or PC for programming, configuration, simulation and the tools required to maintain control. STEP 7 SIMATIC S7 standard package is for S7-300/400,C7 PLC SIMATIC WinAC and product configuration based on PC control programming and maintaining project management tools, STEP 7-Micro/WIN S7-200 series is running on a Windows platform of PLC programming, online simulation software.

(2) PC based control software based on WinAC PC control system allows you to use a personal computer as a programmable logic controller (PLC), the user running the program, running on Windows NT4.0 operating systems are installed the SIMATIC IPC or any other commercial aircraft. WinAC provides two PLC, is a softPLC, running on the user‘s computer as a Windows task. The other is slot PLC (a PC card that is installed on the user‘s computer), it has all functions of PLC hardware. WinAC and SIMATIC S7 series processors are fully compatible, uniform SIMATIC programming tools programming (STEP 7), the program can be run on WinAC, can also run on the S7 series processors.

(3) the HMI software automation project for the user interface software provides human-machine interface (HMI) or SCADA system, supports a wide range of platforms. Human-machine interface software, there are two, one is applied to the machine-level winccflexible, and the other is used to monitor levels of WinCC.

Winccflexible applies to the majority of HMI hardware configuration from the operator‘s Panel to a standard PC can be integrated in the winccflexible effectively complete configuration in STEP 7. Winccflexible for standard PC configuration and all Siemens HMI product, winccflexible not only the configuration software, its monitoring system running version for the Windows platform.

WinCC is a truly open, for the supervisory control and data acquisition SCADA (Supervisory Control and Date Acquisition) software that can run on any standard PC. WinCC simple operation, high reliability, integration with STEP 7 features, hardware failures can be directly into the PLC system, project development time savings. Its design is suitable for a wide range of applications, can be connected to the already existing automation environments, there is a lot of communication interfaces and comprehensive information and data processing capabilities, the latest WinCC5.0 support via IE browser dynamic monitoring of production processes in the Office.