Showing posts from April, 2014

When PLC online, the state appears the statements are not being processed?

In an FC where monitoring occurs when the statements are not being processed
When other FC monitoring are normal, you can connect, ask why?
A: PLC online, the state appears the statements are not being processed?
Indicates that some statements have not been processed. This execution logic of your program about:
There compare, branch, some of the statements will not be executed;
There FC \ FB is conditional call, this time does not match the conditions that are not called.

Siemens PLC battery replacement method

When the PLC user program to be retained in RAM Battery will be used ,Batteries typically 3V or 3.6V non-rechargeable lithium batteries,Battery life is usually about five years ,Battery with a long ,Voltage will drop,When it fell to the data is insufficient to guarantee the RAM ,The program RAM is lost . If the user does not have a backup program ,Will be quite troublesome.
         General Internal PLC has a battery voltage detection circuit ,
When the voltage drops to a certain extent , PLC will alarm ,
Reminder to replace the batteries. PLC to the operating instructions are provided to replace the batteries.In general, the PLC in power,Because the PLC RAM capacitor charging power terminations ,Even if the battery was removed , enough electricity to charge the capacitor RAM data within a period of time , so after a short time if the battery removed (usually five minutes ) and then go put a new battery , the data is not lost .
However, the actual use of PLC different environmental co…

Siemens PLC high-speed counter preset value can be zero right?

Siemens PLC high-speed counter preset value can be set to zero, the purpose you want to use based on the high-speed counter.

every one has a 32-bit high-speed counter current value and a 32-bit preset value,Current and preset values ​​are unsigned integer value.
All counter modes are supported by the current value equal to preset interrupt,
The use of external inputs counter mode support recovery will recover active external interrupt. In addition to modes 0, 1 and 2 except that all counter mode support count direction change interrupt. These can be individually enabled or disabled interrupt condition. To read the value HC0, HC4, and You can use to send commands directly in the main program can be friends.
For example:
LD SM0.0
LD SM0.0
For example:
LD SM0.0
LD SM0.0

How will the time converted to ASCII code?

How to Siemens S7-300 at 8:08:08 on August 8, 2013 by STL how to convert ASCII, preferably with FC in the form of call, multi-thank you!
Here is my answer:
The STEP7 time with BCD code, BCD code can be regarded as a special decimal number, you can use TI_S7 library FC95 HTA to convert.
The following program will MB0 beginning 7 byte hexadecimal number is converted to MB10 beginning 14 byte ASCII code.
      CALL "HTA"
       IN: = P # M 0.0
       N: = W # 16 # 7
       OUT: = P # M 10.0

Siemens PLC serial communication method

1, RS485 serial communication
    Most third-party device support , Siemens S7 PLC by selecting the free port communication mode control serial communication. In the simplest case only send information to the third party equipment , such as printers or the transmission frequency instruction (XMT). In either case , must be achieved through the S7 PLC programming. When you select a free port mode , the user can send commands (XMT), the receiving means (RCV), transmit interrupt , receive interrupt to control the communication port operations.
2, PPI communication
    S7-200CPU PPI protocol is the most basic means of communication , through their original port (PORT0 or PORT1) can achieve communication , S7-200 CPU is the default method of communication . PPI is a master - slave protocol communication, the master - from standing in a token ring network. User network within the CPU can read and write commands , meaning that the network read and write commands are run on the PPI protocol. T…

Siemens S7-200plc how to create or add your own library in the block

Users can put their programming is integrated into the programming software Micro / WIN is. This allows calls to achieve the same function library instruction in programming, rather than several projects simultaneously open file copy. Command library can also be easily passed among multiple programming computers.
New library steps:
1 : Micro / WIN's File (File) menu, choose Creat Library ... (build library) command; Or right-click the command tree Libraries (command library) branch, choose Creat Library ...
2 : Select which subroutine Creat Library dialog box should be integrated into the command library
3 : Set Properties (Properties) tab

Instruction library name
Directory path to generate library files
Version Information

Instruction library name
  Directory path to generate library files
  Version Information
4 : Set the password Protection (Protection) tab
5 : Press the OK button to confirm, the output command library files

Instruction library file extension. Mwl, in the prese…

Siemens 224XP how to modify the baud rate

I use PC / PPI CABLE Cable CPU baud rate is 187.5k,
Again, I use the PC / PPI CABLE cable communications when it is not connected to the CPU And prompts lower baud rate, how to modify the CPU 9.6K baud rate
A: The cable does not support the baud rate of 187.5K
The solution
1, find a support 187.5k cables, rear and PLC connection, the system blocks the baud rate modify.
2, use wipeout.exe program to restore the factory settings of CPU:

Execution of the program "wipeout.exe" not only delete user programs and CPU will revert to the default settings, the network address: 2, Baud Rate: 9.6K.

Note: wipeout.exe software can not be used in conjunction with USB/PPI cable.
Siemens offers a wipeout.exe program can remove programs, and password,restore the factory communication baud rate can be downloaded online from Siemens.

Step7 - Operation

 Forced steps:
a, PLC - Display Force Values;
b, the CPU right, Insert New Object - Variable Table, opened a variable table in the variable table using the menu Variable - Display Force Values.
 forced to use: Open the forced variable window, enter the forced address,
In Force Value set in the actual situation 1 or 0, then we must start forced (right - Force)
2,how to use a query,I,Q, M, etc.
Open any of the OB block, Options - Reference Data - Display, there is a selection prompt, Select View to Be Opened --------- Assignment (Input, Output, Bit Memory, Timers and Counters).

3, Monitor
     Click the Monitor "glasses" icon
    Monitoring a variable: Open the variable table VAT_1 - Input Monitoring address - click the taskbar " Establish a PLC connection icon "

4,backup program copying memory card
Program backup (upload): PC and PLC connection, Create a Project - Menu Bar PLC - Upload Station to PG, interface appears Select Node Address

Program copying m…

Siemens PLC operating system update method

Creating the operating system update with STEP7 cards steps:

1 Download CPU file.

2 Double-click the filename to extract the files

3 Perform "File/S7 Memory Card / Delete" command in the SIMATIC Manager, delete the micro memory card.

4 Select "PLC / Update Operating System" Programming operating system in the SIMATIC Manager, then select the destination directory and open CPU_HD.UPD file to start the programming process.

5 When "The firmware update for the module with order number 6ES7 315-2EH13-0AB0 was transferred successfully to the S7 memory card" appears on the screen
(order number 6ES7 315-2EH13-0AB0 module firmware update has been successfully sent to the S7 memory card) when the alert message, the operating system update card programming is completed.

Operating system updates:

1 CPU power cut where the rack (PS)

2 Disconnect the PLC from the communication network

3 the prepared operating system update card into the CPU

4 where the CPU power rack (…

When s7200plc running, how writer

1, System blocks ------ Properties - "increases the storage area ---" No run mode edit to increase the storage area   No tick .

2, After the connection PLC, the Debug menu ---- under "RUN (run) mode editing program.

Can not download the program

When you write the Siemens program, the first to compile, Then to download. 
If the compiler is wrong, the programming software will prompt

How to solve the Siemens PLC's power LED is not light

1, check if the terminal screw loose or disconnected wires; 
2, replace the power module. 
3, check the external power supply is normal;

How can I delete STEP7 hardware catalog third party DP slave?

If S7-300/400 master station with STEP 7 configuration PROFIBUS network. To configure the third-party DP slave, you need to install the GSD file. You can see it in the Hardware Catalog window after installation. 

To delete STEP7 hardware catalog third party DP slave, first install the "S7DATA" in STEP7 folder> GSD file "GSD" subfolder deleted installation. Then execute the hardware configuration of STEP7 "Options" menu "update catalog" command .

How to change the IP address of the S7-1200?

After entering the device configuration Select the corresponding PLC network view in the directory in the right-hand side, Added to the network view, Click the PLC network interface, The following attributes, Ethernet address (DP network, then on display DP network address), Click the Ethernet address (DP network, then on display DP network address), In "IP Protocol" Modification "Modify the IP address in the project."

PLC crash reason

There are a lot of reason make to plc causes, hardware and software errors make to crashes. 
1, hardware 
(1) I/O channeling, PLC automatically detect I/O errors, enter STOP mode. 
(2) I/O damaged,Program can not execute the command. 
(3) PLC connection module And the address assignment module failed.  
(4) power Interferenceor failure. 
(5) address assignment PLC connection module and a module failure. 
(6) the cable fault. 

2, the software 
(1) infinite loop.  
(2) the program changed the contents of the system parameters area, but no initialization section. 
(3) protection program starts 
(4) data overflow, the step is too large, the watchdog (can be modified DOG time) action.