Tag: ppi

Three methods of Siemens PLC serial communication

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1, RS485 serial communication

Most of the third-party devices support, Siemens S7 PLC can control serial communication by selecting the free port communication mode. In the simplest case, only send commands (XMT) to send information to third-party devices such as printers or inverters. In any case, it must be programmed by S7 PLC. When the free port mode is selected, the user can control the operation of the communication port by sending an instruction (XMT), a receiving finger (RCV), a transmission interrupt, and receiving an interrupt. Siemens S7200

TIM截图20190328170351

2, PPI communication

The PPI protocol is the most basic communication method of the S7-200 CPU. It can communicate through its original port (PORT0 or PORT1), which is the default communication method of the S7-200 CPU. PPI is a master-slave protocol communication, and the master-slave station is in a token ring network. The user network can read and write instructions in the CPU, that is, the network read and write instructions are run on the PPI protocol. Therefore, the PPI can only write the program on the main station side, and the network read and write instructions of the slave station have no meaning.

TIM截图20190328170359

3. MPI communication

MPI communication is a simpler communication method. The MPI network communication rate is 19.2Kbit/s~12Mbit/s. The MPI network supports up to 32 nodes and the maximum communication distance is 50M. The communication distance is long, and the communication distance can also be extended by the repeater, but the repeater also occupies the node. MPI network nodes can usually hang S7-200, human interface, programming devices, and so on.

Siemens PLC S7-200 RS232 wiring method and pin definition?

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The communication port on the S7-200 CPU is RS485.
Its pins are defined as follows:
Pin No. Port 0/Port 1
1 chassis grounding
2 logically
3 RS–485 signal B
4 RTS (TTL)
5 logically
6 +5 V, 100Ω series resistor
7 +24V
8 RS–485 signal A
9 10-bit protocol selection (input)
Connector housing chassis ground
The S7-200 can support various types of communication networks. Make a network selection in the “Set PG/PC Interface” properties dialog. A selected network will be used as an interface. The various interfaces that can access these communication networks include:
Multi-master PPI cable
CP communication card
Ethernet communication card
The following steps allow you to select the communication interface for STEP 7–Micro/WIN. See Figure 7-1.
1. Double-click the icon in the Communication Settings window.
2. Select the interface parameters for STEP 7–Micro/WIN.

What are the Siemens PLC communication protocols?

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Siemens PLC has 4 categories, dozens of model types, different communication protocols supported by PLC are also different.
The protocols supported by the S7-200 series are: PPI, MPI, PROFIBUS, Ethernet, S7 protocol, AS-INTERFACE, USS, MODBUS, and free port.
The protocols supported by the S7-300\400 series are: MPI, PROFIBUS, ETHERNET, ISO, ISO-ON-TCP, MODBUS, etc.
The same point is the same for the same protocol physical transmission medium. For example, the S7 protocol can use DP and Ethernet as transmission media.
The difference is that each protocol corresponds to a different configuration and program

Siemens PLC and inverter use RS485 to realize communication. There is a 485 male connector and a five-core cable. How to weld this connector?

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Siemens and inverters have a variety of communication protocols, such as modbus, USS, DP, etc., but all communicate through the 485 port on Siemens PLC. Siemens’ 485 port definition is 3 feet for A+ and 8 feet for B-, so You can check the manual of the inverter and see which two feet of the communication interface are connected.
remember:
3 feet: RS485 send/receive + signal
8 feet: RS485 transmission / reception – signal
Other feet are generally not connected.

What is MPI cable?

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MPI (Multi-Point Interface) is a technical term for SIEMENS. The interface on the S7-300/400 PLC is MPI. The MPI cable is a cable with one end connected to the MPI interface, and the other end can be in other forms, such as:
PC-MPI cable;
USB-MPI cable;
HMI-MPI cable; hmi-mpi cable from different manufacturers cannot be used universally, wiring pins are different

How to use Siemens MPI / DP RS232 programming cable, how to set step7, how to upload the program

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1,  check if the programming cable hardware is connected to the computer,
2, check if the driver is installed correctly,
3. Open the S7 software, create an empty project, and then set the PGPC interface in “Settings”. If you are an MPI-USB connected PLC, please select MPI. If you are PROFIBUS, please select PROFIBUS, anyway, and the hardware you installed. The programming cable is identical.
Then return to the project interface, click “PLC” to upload the site, jump out of the dialog box and select “Show” and then select the site you want to upload.

Plc300 failed to connect to computer mpi

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Prompt that version v8.2 is instilled onyour computer, this setup cannot instill version v2.0 on top of it. . . The computer is equipped with Siemens software. After plugging in the USB cable, the SIMATIC PC Adapter USB in the device manager still displays a yellow question mark, which cannot be safe. What is the reason?

The reason for the USB adapter driver, now the STEP7 5.5 version software has its own USB communication adapter driver, but it can only be used for the original USB communication adapter of Siemens. Those cottage USB communication adapters will appear in your situation. The solution is to change the STEP7 software with a slightly lower version, such as STEP7 5.4, or manually delete the USB driver file that comes with Siemens, and then manually install the driver that comes with your USB communication adapter.