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Common Problem


We have collected and summarized frequently asked questions from our customers. In most cases, you can find the answers you need. If not, please contact us.

Common Problem


We have collected and summarized frequently asked questions from our customers. In most cases, you can find the answers you need. If not, please contact us.

UN SMART screen dedicated adapter DIP switch settings

UN 232-MPI screen adapter, if the MPI end is extended, what are the extended pins?

2, 3, 7, 8, the adapter needs the CPU to power it,

2 (24V power supply ground), 7 (24V power supply positive pole) provides 24V power supply to the adapter,

3, 8 are RS485 communication pins

UN 300 series modules do not support hot swapping

1. UN300 modules can be used for non-hot-plug rails, but do not support hot-plug.

After the module is removed, the CPU may not find the following modules

2. Hot plugging requires dedicated hardware support. Hot-plugging is supported using hot-plug rails and base modules.

DIP switch settings on the UN 153-1DP slave module

The sum of the number of DIP switches set on the module should be consistent with the DP address set during hardware configuration of 153-1.

Otherwise the SF light on the 153-1 module will be on

What is the difference between UN 331-7PF01 (RTD) and UN 331-7PF11 (TC) temperature modules and UN 331-7KF02 connected to thermal resistance and thermocouple temperature measurement

UN 331-7PF01 (RTD) and UN 331-7PF11 (TC) are dedicated temperature measurement modules,

Support for more types of RTD/thermocouple sensors with channel-to-channel isolation and temperature compensation,

Applicable to more demanding and higher measurement accuracy occasions

UN 331-7KF02 Measuring range card settings

7KF02 has four range blocks, one range block controls 2 channels, the input type of the 2 channels in the same group must be the same,

The direction of the measuring range card should be opposite to the installation direction of the guide rail

When UN 331-7KF02 is connected to the passive sensor current signal, is it necessary to connect an external DC24V power supply?

No, only 7KF02 does not need to be connected to passive sensor current signal, other analog input modules need to be connected to DC24V power supply

Can CP341 module be used behind 153-1DP slave module?

Yes, CP341 can be hung behind 300CPU through IM365 or IM153-1 or directly

When there is no data exchange, UN CP341 has a successful communication indicator

No, when the communication is successful and there is data exchange, the TXD, RXD transceiver indicators will flash

What are the advantages of UN 341-1CH02 compared with 6ES7 341-1CH02

Does UN314CPU support CP341 and Siemens function modules, such as 343 (Ethernet), 350 (high-speed counting)

UNCPU314 integrates MODBUS function, does not support CP341, nor does it support Siemens function modules

Is it possible to monitor programs on UN314CPU using a USB cable?

Yes, UN314CPU can upload, download and monitor programs using USB cable. When using a USB cable, do not plug or unplug the USB-MPI cable on the computer.

The communication protocol supported by the two serial ports of UN314CPU? Whether to support DP communication

X1: MPI, X2: Free port (integrated MODBUS), does not support DP communication

How UNCPU314 realizes Ethernet communication with the host computer

This can be achieved by adding UNNET-MPI, the MPI to Ethernet module. The module supports Siemens' TCP driver.

It can realize the communication with the host computer software, such as: WINCC, Kingview, power control, MCGS, etc.

The order number is UN 972-0CE20-0XA0

Model selection of UN314CPU in Siemens software and hardware configuration

6ES7 314-1AG14-0AB0 V3.3

Can UNPLC use other brands (non-Siemens) communication download lines

No, UNCPU only supports UN or original Siemens communication download cable

Do I need to install a driver for the UN USB-PPI/MPI data cable?

The USB-PPI cable is free of drivers; whether the USB-MPI cable needs to install the driver is related to the software version. The software version is V5.5 and above driver-free.

If the software version is lower than V5.5, you can download the USB-MPI/DP driver from the website and install it

UN RS232-PPI adapter does not support baud rate 187.5kbps, how to set DIP switch

Not supported, RS232-PPI adapter baud rate is 0~28.8kbps adaptive, no need to set DIP switch

Can Siemens function modules be linked after UN200PLC, such as: 243 Ethernet, 253 position control module, weighing module

No, UNCPU is not compatible with Siemens function modules

EM277 corresponds to 300PLC data exchange address

1. The I/O address of the 300 system can be viewed in the hardware configuration of the 300;

2. The I/O address corresponding to the 200CPU is related to the slave device offset setting in the 300 configuration. The I/O address is VB0 (0+offset),

The corresponding addresses are as follows:

Is the function of UN EM277 and Siemens EM277 the same?

Some functions of Siemens EM277, UN EM277 does not support, only supports DP data exchange function, this function is the same as Siemens EM277,

But UN EM277 does not support upload and download programs or touch screen connection

The RTD/TC module is connected to the UN200 series CPU. After power-on, the SF indicator of the module is on, and the PLC information displays I/O errors. Is there a problem with the module?

When 200 series modules, RTD and TC modules (address range AIW) are disconnected, the PLC> message displays "I/O Module Error", "Range Out of Range Error",

This is because the module is disconnected. For RTD modules and TC modules (address range AIW), 32767 is displayed when the channel is paused, and 32000 is out of the channel range;

However, this error does not mean that the module is faulty. The module can be used normally. If all unused channels are shorted, the SF light will not be on and this error message will not exist.

Can UN200 series 4AI/8AI modules connect 0~20mA and 0~10V signals at the same time?

No, these two input signals are determined by DIP switches, and the 8 channels can be either current or voltage

The address range of the UN200 series is Volkswagen's analog input module. What is the address assignment method? How much can hang behind the CPU?

The module address is related to the expansion module number. Taking UN 231-0HH32 as an example, the description is as follows:

7 Volkswagen analog input modules can be hung behind the CPU.

The terminal serial port of UN284CPU does not support MODBUS protocol, how to use Siemens library file

UN248CPU PORT2 (terminal serial port) supports free port, MODBUS protocol, MODBUS library file uses PORT0

What communication protocols does the communication port of UN200CPU support?

1) PPI protocol

2) MPI protocol: not fully supported, can only be used as a slave

3) Modbus RTU protocol

4) Free port mode: user-defined communication protocol for communicating with other serial communication devices (such as serial printers, etc.)

UN200 series PLC high-speed counter function

There are 6 high-speed counts in total, 6 single-phase counts in total, and the highest frequency is 30K;

4 bi-phase counts, the highest frequency is 20K

Can UN200 series digital relay output modules be connected to transistor loads?

Yes, but the action frequency cannot exceed 1Hz, that is, 1s 1 action

UN200 relay output CPU, how to connect the output to the load

UN200 relay output CPU, the output type is dry contact, the working voltage is 24V/220V,

When connecting the load, first connect the 24V/220V voltage in series

What is the current of the UN200CPU local 24V output sensor

800mA, generally used to power expansion modules

Is the PID adjustment function of UN120 series PLC and UN200 series PLC the same?

120 series PLC supports PID function, but does not support self-tuning

200 series PLC supports PID function and self-tuning

What is the reason for the UN200/120CPU SF (system fault) light on?

1) The CPU is not functioning properly or the hardware components are damaged. At this time, if Micro/WIN is still online, you can enter PLC>Information Online View in the command menu, and you can see the specific error description;

2) Program errors, such as entering an infinite loop, or the scanning time caused by programming is too long, and the "watchdog" timeout will also cause the SF light to be on;

3) The CPU power supply voltage may be too low, please check the power supply voltage.

Can UN120 series modules be hung behind UN200CPU?

No, UN200 series and UN120 series products cannot be mixed

How to realize Ethernet communication between UN200/1200 series CPU and upper computer

It can be realized by adding UNNET-PPI, namely PPI, to the Ethernet module. This module supports the TCP driver of Siemens, which can realize the communication with the host computer software, such as: WINCC, Kingview, Power Control, MCGS, etc.

The order number is UN 901-3EB30-0XA0

Data and clock storage time after UN200/120 series PLC is powered off

Data retention: using FLASH storage technology, it can keep power off for a long time,

No battery support, data can be stored for up to 10 years;

Clock Hold: The battery or capacitor keeps the clock data, when the battery or capacitor is dead,

The clock data is restored to the factory value.

Does UN120/200 series PLC support clock function?

support, clock built-in

Number of timers/counters supported by UN120 series PLCs

Both are 256, the same as the number supported by UN200PLC

High-speed counter function of UN120 series PLC

Only supports single-phase counter, 2 channels 20K

UN120 series CPU expansion module function

124CPU can expand 3 modules, 124XP can expand 4 modules

Whether UN120 series transistor output CPU has pulse output function

Yes, two Q0.0, Q0.1, 20K pulse outputs

UN120 series CPU has two serial ports, whether the two serial ports support MODBUS and PPI communication protocols

Yes, it is the same as the communication protocol supported by UN200CPU.

UN124XP analog input signal type, analog addressing

The voltage input, if it is a current signal, should be connected in parallel with a precision resistor. The product is equipped with a precision resistor when it leaves the factory.

How to define the port when UN120 series communication port 1 is connected to the screen

A terminal is RS485 signal +, B terminal is RS485 signal -,

For example, Kunlun on-state TPC7062K, serial port 7 pin is RS485+, 8 pin is RS485-

The hardware wiring is: A-7 B-8

UN120 series PLC digital input type


The digital inputs on UN120/200CPU and expansion modules can be connected to source or sink sensor outputs, as long as the connection mode of the common terminal is changed accordingly (is the power supply L+ connected to the input common terminal, or the power supply M connected to the common terminal).

Programming software and communication cable used by UN120 series PLC

Compatible with UN200 series programming software and communication cables

UN120PLC programming software

Compatible with Siemens 200 programming software.

It is recommended to use V4.0 STEP 7 MicroWIN SP9 version software for UN120/200 series CPU, select CPU224 or above for CPU type, connect the CPU online, and the software will automatically recognize it;

300 series CPU is recommended to use SIMATIC Manager, STEP7 V5.5 software.

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